From mjcal77 at yahoo.com Thu Sep 1 21:56:28 2016 From: mjcal77 at yahoo.com (CL in NC) Date: Fri, 2 Sep 2016 01:56:28 +0000 (UTC) Subject: [AMRadio] Meissner SS expert available? References: <1017727141.177987.1472781388399.ref@mail.yahoo.com> Message-ID: <1017727141.177987.1472781388399@mail.yahoo.com> Is there a Meissner Signal Shifter addict out there? My first VFO was a Meissner Deluxe, and nostalgically picked one up a couple years ago, now finally getting it going. All wax bypass caps were leaking badly, but the filters seemed to accept conditioning and seem to be working just fine. This one is also a wartime production as it has glass 6L6 and 6F6 with the additional 10K across the osc. screen resistor R11 with a decal note about this on one of the coil cans, advising you to remove the 10K if you use metal tubes. The question concerns a wiring and component difference. Per the schematic, coming off choke 6, a PS filter choke is R12, 4K 10W feeding filter cap C19. From there it goes through R13 a 1K 5W to the series string of a VR105 and VR150. This unit does not have R12, choke 6 feeds C19 direct and R13 goes to the regulators. Anybody know if this was a production change? Current draw through R13, the regulators and normal load is only 25MA, about perfect for them. There appears to be no terminal that the wire lead of choke 6 would have gone to for one end of an R12 to attach to, and R13 appears to not have been disturbed on one end since it was built, the other has been resoldered though. R13 was shown in the manual to be a 1K, the resistor actually reads about 1.5K, but 'body-end-dot' may indicate a 1.4K, there is a bit of yellow on one end, the body is either burned or black, and there is no dot. Not sure of a design where you would come out of a choke, then through a resistor to get to the filter cap, combination smoothing choke and smoothing resistor perhaps or brother in law effect. Charlie, W4MEC in NC From mjcal77 at yahoo.com Sun Sep 4 21:14:41 2016 From: mjcal77 at yahoo.com (CL in NC) Date: Mon, 5 Sep 2016 01:14:41 +0000 (UTC) Subject: [AMRadio] Meissner mystery solved and Shelby report References: <285359191.97081.1473038081564.ref@mail.yahoo.com> Message-ID: <285359191.97081.1473038081564@mail.yahoo.com> My question about components in the Meissner schematic, but not in mine may have been answered.? They are supposed to be in mine and somebody changed them out using only a 1.4K.? Apparently, the stock 2 section cap, 15UF at 500 and 10 at 450 was more economical than something else and resistors were cheap.???R12, feeding the 10UF 450 volt section was in there to maintain a safety margin in the 450 volt cap.? If it is not in there, since the Meissner was rated to 125VAC in, the B+ rises to almost 450 volts to that part of the cap without R12 if you dial in 125 volts in.? With the required 4K R12 in there, you drop 140 volts or so, down, keeping the 450 rating from being approached.? The 4K and R13, a 1K, combine to make a 5K resistor feeding the regulator tubes, with the whole load being in the 30MA range either in STBY or operate.? Now I know you can all breathe easier. Regarding the Selby NC hamfest, which used to be a premier event,? I believe the almost hurricane than came through stopped a lot of travelers. There was a lot of gear there at good prices and much of it sold. Here are some pix: http://www.virhistory.com/ham/shelby_2016.htm Like all of the older fests, Shelby has suffered over the years, there are no big vendors other than MFJ, and the Elecraft folks who you can only order from. MFJ never used to sell direct when they showed up, you always had to go to a vendor and buy it from them, even if MFJ just handed it over to them to sell to you. MFJ was selling direct this year and last too. Even the ESRC guy didn't show up with his tubes to sell, but he may have been hurricaned in since he comes out of FLA. Rumor has it that Shelby may return to Dallas, NC. The fest left Shelby after the city of Shelby raised the rent, but the local businesses owners saw a big decline in income and pleaded with the local govt. to mend its ways and bring the fest back. It's been back 2 years now and is failing. Due to the Shelby Fairground being in financial difficulty, they may have to leave again. While the hamfest and cancelled motel reservations may have suffered, Bridges BBQ, a major ham op feeding trough actually had to close for the day after it ran out of food. I have never seen that happen before. Charlie, W4MEC in NC From mjcal77 at yahoo.com Tue Sep 6 20:53:30 2016 From: mjcal77 at yahoo.com (CL in NC) Date: Wed, 7 Sep 2016 00:53:30 +0000 (UTC) Subject: [AMRadio] BAMA edibris site and TX62 References: <1172637699.784316.1473209610350.ref@mail.yahoo.com> Message-ID: <1172637699.784316.1473209610350@mail.yahoo.com> Anybody else getting the 'download limit reached" message. I haven't downloaded anything in several days and have not hit this wall before. I know mods.dk does this, but this is a first for bama. Was trying to get a look see at the Ameco TX62 manual parts list as I only have a few pages of the original. Need to find out the wattage of R55, the 10 ohm feeding the rectifier for the 12 volt output. Looks like a 2, but it is not a normal carbon composition. Charlie, W4MEC in NC From manualman at juno.com Tue Sep 6 22:45:41 2016 From: manualman at juno.com (manualman at juno.com) Date: Tue, 6 Sep 2016 22:45:41 -0400 Subject: [AMRadio] BAMA edibris site and TX62 Message-ID: The posted TX-62 manual does not include the alignment instructions nor the parts list. Pete, wa2cwa On Wed, 7 Sep 2016 00:53:30 +0000 (UTC) CL in NC via AMRadio writes: > Anybody else getting the 'download limit reached" message. I haven't > downloaded anything in several days and have not hit this wall > before. I know mods.dk does this, but this is a first for bama. > > Was trying to get a look see at the Ameco TX62 manual parts list as > I only have a few pages of the original. Need to find out the > wattage of R55, the 10 ohm feeding the rectifier for the 12 volt > output. Looks like a 2, but it is not a normal carbon composition. > > Charlie, W4MEC in NC From wa1qix at piesky.com Sat Sep 17 06:53:05 2016 From: wa1qix at piesky.com (Steve WA1QIX) Date: Sat, 17 Sep 2016 06:53:05 -0400 Subject: [AMRadio] Calling the Lonely Guys Sat 9/17/2016 8:00AM on 3875 Message-ID: <201609171043.u8HAhisj061344@mx1.piesky.com> Calling the Lonely Guys. The Lonely Guys net will start up on Saturday 9/17/2016 (today!) at 8:00 AM on 3875kHz. See you there! Regards, Steve From mjcal77 at yahoo.com Thu Sep 22 22:41:49 2016 From: mjcal77 at yahoo.com (CL in NC) Date: Fri, 23 Sep 2016 02:41:49 +0000 (UTC) Subject: [AMRadio] FCC's AM power References: <644138908.3346178.1474598509954.ref@mail.yahoo.com> Message-ID: <644138908.3346178.1474598509954@mail.yahoo.com> I was pondering the old rule of thumb for power in the sidebands of a 100% modulated AM transmitter and got to wondering about our power restriction on AM. A CW station or SSB station can put 1500 watts into one information carrying signal. So, why is it we are restricted to only 375 watts of plate modulated AM which supposedly is equal to 1500 PEP watts of CW and SSB, when this really only equals 93.75 watts per sideband for a total of 187.5 watts of actual information signal. If we could put the equivalent 1500 watts into our information carrying part of our signal, that would be 750 watts per information carrying sideband, 1500 watts of actual info signal, being generated by an unmodulated power out of 3000 watts. This would be a total Power(total)* of 4500 watts, but, even if we rolled it back to a total power of 1500, that's a 1000 watt carrier with 500 total sideband information signals, still only 33% of the CW/SSB 1500. So, to be absolutely fair, with this difference in sideband information carrying powers, it would seem a power reduction is in order for CW and SSB operators such that their actual information carrying signal is not greater than the total power in the sidebands of an equivalent legal power out DSB AM signal, 187.5 watts PEP. Of course that will never happen, but there is a great inequality in this restriction that maybe the ACLU could take on as discrimination against the bi-sideband lifestyle. Never ponder after two PBR's Charlie, W4MEC in NC * Power(total) = Carrier power X (1 + m(sqrd) / 2) where m = decimal equiv. of mod percent From k4kyv at charter.net Sat Sep 24 20:13:33 2016 From: k4kyv at charter.net (Donald Chester) Date: Sat, 24 Sep 2016 19:13:33 -0500 Subject: [AMRadio] FCC's AM power In-Reply-To: <644138908.3346178.1474598509954@mail.yahoo.com> References: <644138908.3346178.1474598509954.ref@mail.yahoo.com> <644138908.3346178.1474598509954@mail.yahoo.com> Message-ID: <007501d216c1$a7406480$f5c12d80$@charter.net> With an AM signal modulated 100%, two-thirds of the power is in the carrier, and one third in the sidebands. A 1000 watt carrier has 500 watts p.e.p. in the sidebands at 100% modulation. The carrier and sidebands make up two separate sets of signals, transmitted on or about the same frequency. 1000 watts carrier + 500 watts sidebands = 1500 watts total. From garyschafer at largeriver.net Sun Sep 25 00:03:52 2016 From: garyschafer at largeriver.net (Gary Schafer) Date: Sat, 24 Sep 2016 23:03:52 -0500 Subject: [AMRadio] FCC's AM power In-Reply-To: <007501d216c1$a7406480$f5c12d80$@charter.net> References: <644138908.3346178.1474598509954.ref@mail.yahoo.com><644138908.3346178.1474598509954@mail.yahoo.com> <007501d216c1$a7406480$f5c12d80$@charter.net> Message-ID: <3FC974C690EA4152AC035A91C520E75A@garyPC> A little correction here: A 1000 watt carrier modulated 100% has 500 watts AVERAGE power in the side bands. 1000 watts carrier plus 500 watts AVERAGE power sidebands = 1500 watts of AVERAGE power. The PEP (peak envelope power) will be 4000 watts. 73 Gary K4FMX > -----Original Message----- > From: AMRadio [mailto:amradio-bounces at mailman.qth.net] On Behalf Of > Donald Chester > Sent: Saturday, September 24, 2016 7:14 PM > To: 'CL in NC'; amradio at mailman.qth.net > Subject: Re: [AMRadio] FCC's AM power > > With an AM signal modulated 100%, two-thirds of the power is in the > carrier, > and one third in the sidebands. A 1000 watt carrier has 500 watts p.e.p. > in > the sidebands at 100% modulation. > > The carrier and sidebands make up two separate sets of signals, > transmitted > on or about the same frequency. > > 1000 watts carrier + 500 watts sidebands = 1500 watts total. > From edwmullin at aol.com Sun Sep 25 08:36:40 2016 From: edwmullin at aol.com (Ed) Date: Sun, 25 Sep 2016 08:36:40 -0400 Subject: [AMRadio] FCC's AM power In-Reply-To: <3FC974C690EA4152AC035A91C520E75A@garyPC> References: <644138908.3346178.1474598509954.ref@mail.yahoo.com> <644138908.3346178.1474598509954@mail.yahoo.com> <007501d216c1$a7406480$f5c12d80$@charter.net> <3FC974C690EA4152AC035A91C520E75A@garyPC> Message-ID: You could start with a 1500 watt carrier, then 'downwards' modulate and meet the requirement. But most people would tell you that violates the rule. It's just this sort of conversation that proves how ridiculous the power rule is. If people under the rule can't even agree how it's applied, and those enforcing the rule can't provide a simple method to measure or interpret it, it's a waste. Basing a rule on a measurement that few people can measure accurately, let alone define is simple Government lawyer stupidity. To be effective rules should simple to understand and easy to apply. The old rule of measuring the input power to the final was simpler, easy to measure, for amateurs, easy to understand and would have encouraged folks to design more and more efficient systems. I think the problem with it was the FCC personnel wouldn't or couldn't go around connecting meters to potentially lethal final power supplies. Or maybe they just aren't technical enough to figure it out. Nowadays with so few folks doing real desist work, especially on AM, there's little motivation to change it. On the bright side, if you're not grossly exceeding the limit, odds are no ones going to be able to figure it out. Run a well designed rig with clean modulation and low spurious emissions and you'll be far ahead of most of the crowd anyway. A few watts here and there isn't getting noticed by anyone. VR, Ed Mullin > On Sep 25, 2016, at 12:03 AM, Gary Schafer wrote: > > AMRadio] FCC's AM power From ars.w5omr at gmail.com Sun Sep 25 09:17:03 2016 From: ars.w5omr at gmail.com (Geoff) Date: Sun, 25 Sep 2016 08:17:03 -0500 Subject: [AMRadio] FCC's AM power In-Reply-To: References: <644138908.3346178.1474598509954.ref@mail.yahoo.com> <644138908.3346178.1474598509954@mail.yahoo.com> <007501d216c1$a7406480$f5c12d80$@charter.net> <3FC974C690EA4152AC035A91C520E75A@garyPC> Message-ID: <3b6f6f7e-de43-31b4-7ec8-44416fd1ca4f@gmail.com> On 09/25/2016 07:36 AM, Ed via AMRadio wrote: > You could start with a 1500 watt carrier, then 'downwards' modulate and meet the requirement. But most people would tell you that violates the rule. > > It's just this sort of conversation that proves how ridiculous the power rule is. If people under the rule can't even agree how it's applied, and those enforcing the rule can't provide a simple method to measure or interpret it, it's a waste. Basing a rule on a measurement that few people can measure accurately, let alone define is simple Government lawyer stupidity. > > To be effective rules should simple to understand and easy to apply. > > The old rule of measuring the input power to the final was simpler, easy to measure, for amateurs, easy to understand and would have encouraged folks to design more and more efficient systems. I think the problem with it was the FCC personnel wouldn't or couldn't go around connecting meters to potentially lethal final power supplies. Or maybe they just aren't technical enough to figure it out. Nowadays with so few folks doing real desist work, especially on AM, there's little motivation to change it. > > On the bright side, if you're not grossly exceeding the limit, odds are no ones going to be able to figure it out. Run a well designed rig with clean modulation and low spurious emissions and you'll be far ahead of most of the crowd anyway. A few watts here and there isn't getting noticed by anyone. > Hmmmm... maybe time to trot this out, again... http://www.qsl.net/wa5bxo/asyam/aam3.html 73 = Best Regards, -Geoff/W5OMR From donroden at hiwaay.net Sun Sep 25 10:49:16 2016 From: donroden at hiwaay.net (donroden at hiwaay.net) Date: Sun, 25 Sep 2016 09:49:16 -0500 Subject: [AMRadio] FCC's AM power In-Reply-To: References: <644138908.3346178.1474598509954.ref@mail.yahoo.com> <644138908.3346178.1474598509954@mail.yahoo.com> <007501d216c1$a7406480$f5c12d80$@charter.net> <3FC974C690EA4152AC035A91C520E75A@garyPC> Message-ID: <20160925094916.Horde.8NiGX2-W13AReMmuPlHpA6y@webmail.hiwaay.net> Quoting Ed via AMRadio : > You could start with a 1500 watt carrier, then 'downwards' modulate > and meet the requirement. But most people would tell you that > violates the rule. No, it would not violate the rule. In fact, most amateurs could measure this power requirement with a simple Bird 43 wattmeter or an MFJ wattmeter. Don W4DNR From ranchorobbo at gmail.com Sun Sep 25 11:15:52 2016 From: ranchorobbo at gmail.com (Rob Atkinson) Date: Sun, 25 Sep 2016 10:15:52 -0500 Subject: [AMRadio] FCC's AM power In-Reply-To: <3FC974C690EA4152AC035A91C520E75A@garyPC> References: <644138908.3346178.1474598509954.ref@mail.yahoo.com> <644138908.3346178.1474598509954@mail.yahoo.com> <007501d216c1$a7406480$f5c12d80$@charter.net> <3FC974C690EA4152AC035A91C520E75A@garyPC> Message-ID: > > The PEP (peak envelope power) will be 4000 watts. Mathematically that's correct but from a practical useable power standpoint, average is what matters, not some transient peak that has a nanosecond duration. The AM power limit should have been left as it was, with dc input to the final being measured. PEP is entirely impractical and a ridiculous thing to try to measure with an kind of accuracy. It makes the American power limit almost as much a joke as the RF Exposure limit nonsense. AM broadcast stations measure antenna current. FCC gave them some reasonable power method. Hams have something that's almost fiction. What about the 375 watts? Firstly, no one can exactly measure 375 watts. Secondly, it doesn't take into account asymmetry if we're going to play by the delusional PEP rule. I cringe when I hear "I'm running the legal 375 watts." 73 Rob K5UJ From k4kyv at charter.net Sun Sep 25 16:25:01 2016 From: k4kyv at charter.net (Donald Chester) Date: Sun, 25 Sep 2016 15:25:01 -0500 Subject: [AMRadio] FCC's AM power In-Reply-To: <922114672.4200188.1474763308256@mail.yahoo.com> References: <922114672.4200188.1474763308256.ref@mail.yahoo.com> <922114672.4200188.1474763308256@mail.yahoo.com> Message-ID: <004201d2176a$e4d210b0$ae763210$@charter.net> Yep, it's kind of fun to view or launch one of those discussions and see what follows. The thing about it is that many if not most of to-day's hams have limited notion about what p.e.p. is, let alone how to measure it. Just look at any thread on that topic started up ham radio websites like QRZ.com and eHam, and it goes immediately to a long discussion and debate, with a lot of valid and mis-information, speculation and urban legends amongst hams who do not understand the basic concept in the first place. Don k4kyv > -----Original Message----- > From: CL in NC [mailto:mjcal77 at yahoo.com] > Sent: Saturday, 24 September, 2016 19:28 > To: Donald Chester > Subject: RE: [AMRadio] FCC's AM power > > That's what I said, just being humorous about the disparity... From k4kyv at charter.net Sun Sep 25 16:33:10 2016 From: k4kyv at charter.net (Donald Chester) Date: Sun, 25 Sep 2016 15:33:10 -0500 Subject: [AMRadio] FCC's AM power In-Reply-To: References: <644138908.3346178.1474598509954.ref@mail.yahoo.com> <644138908.3346178.1474598509954@mail.yahoo.com> <007501d216c1$a7406480$f5c12d80$@charter.net> <3FC974C690EA4152AC035A91C520E75A@garyPC> Message-ID: <004401d2176c$07fb4420$17f1cc60$@charter.net> > It's just this sort of conversation that proves how ridiculous the power rule is. > If people under the rule can't even agree how it's applied, and those > enforcing the rule can't provide a simple method to measure or interpret it, > it's a waste. ... I think the problem with it > was the FCC personnel wouldn't or couldn't go around connecting meters to > potentially lethal final power supplies. Or maybe they just aren't technical > enough to figure it out That's what they claimed, but the real reason was that jerk who at the time was head of the Private Radio Bureau, the amateur rulemaking division of the FCC, didn't like AM and wanted to get rid of it. Under his leadership they used fraudulent arguments and dodged issues brought up in response to opposing comments to push the ruling through with the non-technical lawyer types who made up the Commissioners. He's the same one who originally pushed Docket 20777 back in the mid 1970s, the original regulation-by-bandwidth NPRM, that would have eliminated AM altogether. Don k4kyv From donroden at hiwaay.net Sun Sep 25 16:43:51 2016 From: donroden at hiwaay.net (donroden at hiwaay.net) Date: Sun, 25 Sep 2016 15:43:51 -0500 Subject: [AMRadio] FCC's AM power In-Reply-To: <004201d2176a$e4d210b0$ae763210$@charter.net> References: <922114672.4200188.1474763308256.ref@mail.yahoo.com> <922114672.4200188.1474763308256@mail.yahoo.com> <004201d2176a$e4d210b0$ae763210$@charter.net> Message-ID: <20160925154351.Horde.Ibwj8ci2YjQziX4fXn-iHC2@webmail.hiwaay.net> Physics am Physics. Broadcast or amateur doesn't change 100+ years of Physics. Don W4DNR Quoting Donald Chester : > Yep, it's kind of fun to view or launch one of those discussions and > see what follows. > > The thing about it is that many if not most of to-day's hams have > limited notion about what p.e.p. is, let alone how to measure it. > Just look at any thread on that topic started up ham radio websites > like QRZ.com and eHam, and it goes immediately to a long discussion > and debate, with a lot of valid and mis-information, speculation and > urban legends amongst hams who do not understand the basic concept > in the first place. > > Don k4kyv > >> -----Original Message----- >> From: CL in NC [mailto:mjcal77 at yahoo.com] >> Sent: Saturday, 24 September, 2016 19:28 >> To: Donald Chester >> Subject: RE: [AMRadio] FCC's AM power >> >> That's what I said, just being humorous about the disparity... > > ______________________________________________________________ > Our Main Website: http://www.amfone.net > AMRadio mailing list > Archives: http://mailman.qth.net/pipermail/amradio/ > List Rules (must read!): http://w5ami.net/amradiofaq.html > List Home: http://mailman.qth.net/mailman/listinfo/amradio > Post: AMRadio at mailman.qth.net > To unsubscribe, send an email to amradio-request at mailman.qth.net with > the word unsubscribe in the message body. > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to donroden at hiwaay.net From oldrotorheadsarge at outlook.com Sun Sep 25 17:33:53 2016 From: oldrotorheadsarge at outlook.com (Robert Bethman) Date: Sun, 25 Sep 2016 21:33:53 +0000 Subject: [AMRadio] AM Power Message-ID: Physics is physics, but these *new* folks don't know the subject matter! All we are doing is disturbing electrons by sending messages. Bob - N0DGN [ Have studied Classical Physics, and Nuclear Physics ] Still doesn't mean I can better describe PEP! From donroden at hiwaay.net Sun Sep 25 19:50:08 2016 From: donroden at hiwaay.net (donroden at hiwaay.net) Date: Sun, 25 Sep 2016 18:50:08 -0500 Subject: [AMRadio] AM Power In-Reply-To: Message-ID: <20160925185008.Horde.8QHTcn9AeKH65XhaH0LNm5-@webmail.hiwaay.net> LOL !! I spent 45 years keeping 50KW AMs on the air, but I am still learning every day. I feel bad for the electrons, but something has to move. Don W4DNR Quoting Robert Bethman : > Physics is physics, but these *new* folks don't know the subject > matter! All we are doing is disturbing electrons by sending messages. > Bob - N0DGN [ Have studied Classical Physics, and Nuclear Physics ] > Still doesn't mean I can better describe PEP! > ______________________________________________________________ > Our Main Website: http://www.amfone.net > AMRadio mailing list > Archives: http://mailman.qth.net/pipermail/amradio/ > List Rules (must read!): http://w5ami.net/amradiofaq.html > List Home: http://mailman.qth.net/mailman/listinfo/amradio > Post: AMRadio at mailman.qth.net > To unsubscribe, send an email to amradio-request at mailman.qth.net with > the word unsubscribe in the message body. > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to donroden at hiwaay.net From k4kyv at charter.net Sun Sep 25 23:08:19 2016 From: k4kyv at charter.net (Donald Chester) Date: Sun, 25 Sep 2016 22:08:19 -0500 Subject: [AMRadio] FCC's AM power In-Reply-To: References: <644138908.3346178.1474598509954.ref@mail.yahoo.com> <644138908.3346178.1474598509954@mail.yahoo.com> <007501d216c1$a7406480$f5c12d80$@charter.net> <3FC974C690EA4152AC035A91C520E75A@garyPC> Message-ID: <005701d217a3$3c0a6cf0$b41f46d0$@charter.net> > What about the 375 watts? Firstly, no one can exactly measure 375 watts. > Secondly, it doesn't take into account asymmetry if we're going to play by the > delusional PEP rule. I cringe when I hear "I'm running the legal 375 watts." There is NOTHING in Part 97 that even mentions 375 watts. From k4kyv at charter.net Sun Sep 25 23:11:14 2016 From: k4kyv at charter.net (Donald Chester) Date: Sun, 25 Sep 2016 22:11:14 -0500 Subject: [AMRadio] AM Power In-Reply-To: References: Message-ID: <006001d217a3$a4426b10$ecc74130$@charter.net> > Physics is physics, but these *new* folks don't know the subject matter! All > we are doing is disturbing electrons by sending messages. Let the newbies figure it out for themselves. No point in providing aid and comfort to the enemy. From ars.w5omr at gmail.com Mon Sep 26 03:40:01 2016 From: ars.w5omr at gmail.com (Geoff) Date: Mon, 26 Sep 2016 02:40:01 -0500 Subject: [AMRadio] AM Power In-Reply-To: <006001d217a3$a4426b10$ecc74130$@charter.net> References: <006001d217a3$a4426b10$ecc74130$@charter.net> Message-ID: <8b795d6b-13c2-275a-4799-d002d6d263dc@gmail.com> On 09/25/2016 10:11 PM, Donald Chester wrote: > Let the newbies figure it out for themselves. No point in providing aid and > comfort to the enemy. > The newbies aren't our enemy. Ignorant bureaucrats, within our own ranks are the problem. From http://www.qsl.net/wa5bxo/asyam/aam3.html (which, btw, was co-authored by some cat in Woodlawn, TN - ever heard of him? ;-) ) [block quote] The FCC regulations at the time stated that the general class license holders could run no more than 1000 watts DC input power to the plate circuit of the RF final amplifier. This was easy to measure with DC meters. The plate supply voltage was multiplied times the plate supply current, and the product was the DC input in watts. RF amplifier efficiency determined how much output power could be achieved. The efficiency of a screen modulated RF output stage or a class B RF linear amplifier at carrier level is about 33% to 35%, giving you about 330 to 350 watts of carrier output on AM for the maximum legal input power of 1000 watts. On the other hand, a plate modulated class C amplifier has about 75 percent efficiency, giving you about 750 watts of AM carrier output for that 1000 watts input. And the output tube in the final RF amplifier runs a lot cooler in class C than in class B AM linear operation, so smaller tubes can be used. But the only practical way for hams to get high RF amplifier efficiency with AM was to apply the modulating audio voltage to the plate supply of the RF final, and the audio circuitry required to do this must be capable of at least 500 watts of audio. So, to get the extra power output within the legal definitions, most of the big-gun operators opted for the high-level plate modulation method. The high-level modulation method is the application of the modulating voltage to the plate circuit of the class C final, causing the output amplitude to vary in accordance with the applied modulation. One hundred percent (100%) modulation was generally defined as the point where the maximum modulating voltage, during its negative half cycle, opposed the DC supply voltage sufficiently to reduce it to zero. If this voltage dipped below zero, over-modulation and splatter were the result. Most people agreed that the peak of the positive half cycle of the modulating audio voltage, added to the DC supply, could go as high as necessary to faithfully reproduce the audio as an image of the microphone output. Even if the positive peak was more than two times the amplitude of the negative peak, the modulation was not considered illegal unless it contained distortion products that caused splatter over an excessive bandwidth. Over-modulation was only considered to occur at the point where modulation characteristic became non-linear, producing distortion and splatter. The audio voltage from a microphone is often not symmetrical, unlike a sine wave from a signal generator. This asymmetry is a natural quality of speech and other sounds. This article discusses the use of voice waveform asymmetry in AM systems. When an AM transmitter is 100% modulated by a pure sine wave, the PEP (Peak Envelope Power), is 4 times the un-modulated carrier power. This is because the Audio Voltage modulating the carrier doubles the RF voltage at the peak, since the load resistance is constant, the RF current doubles at the same instant as the RF voltage. Since P = E * I, then P at the instant of the positive peak must be 4 times greater than the power of the original carrier... [end quote] the rest of the article, with graphical presentations and solutions (and Don Chester's comments), are located at http://www.qsl.net/wa5bxo/asyam/aam3.html As someone who enjoyed the effects of this circuit and design, lets just say, that watching a pep meter bang the 1000kW scale end on audio peaks with just a 100w carrier, and the monitor scope not hitting the 100% negative line is a feeling that was difficult, at best, to describe. 73 = Best Regards, -Geoff/W5OMR From k9cox at charter.net Mon Sep 26 03:49:36 2016 From: k9cox at charter.net (Ross Stenberg) Date: Mon, 26 Sep 2016 02:49:36 -0500 Subject: [AMRadio] FCC's AM power In-Reply-To: <005701d217a3$3c0a6cf0$b41f46d0$@charter.net> References: <644138908.3346178.1474598509954.ref@mail.yahoo.com> <644138908.3346178.1474598509954@mail.yahoo.com> <007501d216c1$a7406480$f5c12d80$@charter.net> <3FC974C690EA4152AC035A91C520E75A@garyPC> <005701d217a3$3c0a6cf0$b41f46d0$@charter.net> Message-ID: I know that some my be dismayed by this however there are unscrupulous hams the routinely run homebrew AM transmitters such as a 4-1000 modulated by a pair of 4-400?s in excess of whatever one thinks is ?the legal limit?! There are others that use old broadcast AM transmitters beyond ham limits as well! 73 Ross K9COX Sent from Mail for Windows 10 From ars.w5omr at gmail.com Mon Sep 26 03:55:41 2016 From: ars.w5omr at gmail.com (Geoff) Date: Mon, 26 Sep 2016 02:55:41 -0500 Subject: [AMRadio] FCC's AM power In-Reply-To: References: <644138908.3346178.1474598509954.ref@mail.yahoo.com> <644138908.3346178.1474598509954@mail.yahoo.com> <007501d216c1$a7406480$f5c12d80$@charter.net> <3FC974C690EA4152AC035A91C520E75A@garyPC> <005701d217a3$3c0a6cf0$b41f46d0$@charter.net> Message-ID: <07f8be1f-e338-c8cc-016f-71a722205e80@gmail.com> On 09/26/2016 02:49 AM, Ross Stenberg wrote: > I know that some my be dismayed by this however there are unscrupulous hams the routinely run homebrew AM transmitters such as a 4-1000 modulated by a pair of 4-400?s in excess of whatever one thinks is ?the legal limit?! There are others that use old broadcast AM transmitters beyond ham limits as well! > > 73 Ross K9COX > > Sent from Mail for Windows 10 > "legal limit" these days, is simply 1,500w PEP output to the antenna. * When an AM transmitter is 100% modulated by a pure sine wave, the PEP (Peak Envelope Power), is 4 times the un-modulated carrier power. This is because the Audio Voltage modulating the carrier doubles the RF voltage at the peak, since the load resistance is constant, the RF current doubles at the same instant as the RF voltage. Since P = E * I, then P at the instant of the positive peak must be 4 times greater than the power of the original carrier * From ars.w5omr at gmail.com Mon Sep 26 03:59:32 2016 From: ars.w5omr at gmail.com (Geoff) Date: Mon, 26 Sep 2016 02:59:32 -0500 Subject: [AMRadio] FCC's AM power In-Reply-To: References: <644138908.3346178.1474598509954.ref@mail.yahoo.com> <644138908.3346178.1474598509954@mail.yahoo.com> <007501d216c1$a7406480$f5c12d80$@charter.net> <3FC974C690EA4152AC035A91C520E75A@garyPC> <005701d217a3$3c0a6cf0$b41f46d0$@charter.net> Message-ID: <9c534408-c1ef-7778-c45b-6ed3c37e0aad@gmail.com> On 09/26/2016 02:49 AM, Ross Stenberg wrote: > I know that some my be dismayed by this however there are unscrupulous hams the routinely run homebrew AM transmitters such as a 4-1000 modulated by a pair of 4-400?s in excess of whatever one thinks is ?the legal limit?! There are others that use old broadcast AM transmitters beyond ham limits as well! > I ran a pair of 250TH's modulated by another pair. Separate power supplies, 1500v @100mA on the final. 3kVDC on the modulators, resting at 120mA. At -rest-, there was more power being dissipated by the modulator, than there was in the final, but man did that thing sound -good-! From frsahu0003 at embarqmail.com Mon Sep 26 06:35:43 2016 From: frsahu0003 at embarqmail.com (FRANK HUGHES hughes) Date: Mon, 26 Sep 2016 06:35:43 -0400 (EDT) Subject: [AMRadio] AM power In-Reply-To: <888844076.53722886.1474886067582.JavaMail.root@embarqmail.com> Message-ID: <1257313114.53723690.1474886143297.JavaMail.root@embarqmail.com> As a newbie, all I know about PEP is that I have less and less with every passing decade Frank KJ4OLL From k4kyv at charter.net Mon Sep 26 11:12:29 2016 From: k4kyv at charter.net (Donald Chester) Date: Mon, 26 Sep 2016 10:12:29 -0500 Subject: [AMRadio] AM Power In-Reply-To: <8b795d6b-13c2-275a-4799-d002d6d263dc@gmail.com> References: <006001d217a3$a4426b10$ecc74130$@charter.net> <8b795d6b-13c2-275a-4799-d002d6d263dc@gmail.com> Message-ID: <000c01d21808$65d0bf70$31723e50$@charter.net> > The newbies aren't our enemy. Ignorant bureaucrats, within our own ranks > are the problem. Exactly. Never meant to imply that the newbies themselves are the "enemy". From oldrotorheadsarge at outlook.com Mon Sep 26 12:04:21 2016 From: oldrotorheadsarge at outlook.com (Robert Bethman) Date: Mon, 26 Sep 2016 16:04:21 +0000 Subject: [AMRadio] AM Power In-Reply-To: <000c01d21808$65d0bf70$31723e50$@charter.net> References: <006001d217a3$a4426b10$ecc74130$@charter.net> <8b795d6b-13c2-275a-4799-d002d6d263dc@gmail.com> <000c01d21808$65d0bf70$31723e50$@charter.net> Message-ID: There is a LOT of truth in Don's post. While I cannot explain it in verbal terminology, I do indeed do a good job using and Oscilloscope with only a High Z microphone as a demonstration of human voice patterns. It is an eye opener to folks to perform this demo with male AND female voices! Regards, Bob N0DGN -----Original Message----- From: AMRadio [mailto:amradio-bounces at mailman.qth.net] On Behalf Of Donald Chester Sent: Monday, September 26, 2016 11:12 AM To: 'Geoff' ; amradio at mailman.qth.net Subject: Re: [AMRadio] AM Power > The newbies aren't our enemy. Ignorant bureaucrats, within our own > ranks are the problem. Exactly. Never meant to imply that the newbies themselves are the "enemy". From steinerviolinist at gmail.com Mon Sep 26 16:18:37 2016 From: steinerviolinist at gmail.com (Oliver Steiner) Date: Mon, 26 Sep 2016 16:18:37 -0400 Subject: [AMRadio] FCC's AM power In-Reply-To: <9c534408-c1ef-7778-c45b-6ed3c37e0aad@gmail.com> References: <644138908.3346178.1474598509954.ref@mail.yahoo.com> <644138908.3346178.1474598509954@mail.yahoo.com> <007501d216c1$a7406480$f5c12d80$@charter.net> <3FC974C690EA4152AC035A91C520E75A@garyPC> <005701d217a3$3c0a6cf0$b41f46d0$@charter.net> <9c534408-c1ef-7778-c45b-6ed3c37e0aad@gmail.com> Message-ID: I'm not clear about the distinction between "peak power" and "peak envelope power" (If there is one). My Autek power/swr meter lets me select between average power and peak power, but am I monitoring peak *envelope* power when I have it switched to the "peak power" position? --- or is peak envelope power only possible to determine with a calibrated oscilloscope? I'm grateful to read your answers to this. Ollie W2QXR On 9/26/16, Geoff wrote: > > > On 09/26/2016 02:49 AM, Ross Stenberg wrote: >> I know that some my be dismayed by this however there are unscrupulous >> hams the routinely run homebrew AM transmitters such as a 4-1000 >> modulated by a pair of 4-400?s in excess of whatever one thinks is ?the >> legal limit?! There are others that use old broadcast AM transmitters >> beyond ham limits as well! >> > > I ran a pair of 250TH's modulated by another pair. > > Separate power supplies, 1500v @100mA on the final. 3kVDC on the > modulators, resting at 120mA. > > At -rest-, there was more power being dissipated by the modulator, than > there was in the final, but man did that thing sound -good-! > > > ______________________________________________________________ > Our Main Website: http://www.amfone.net > AMRadio mailing list > Archives: http://mailman.qth.net/pipermail/amradio/ > List Rules (must read!): http://w5ami.net/amradiofaq.html > List Home: http://mailman.qth.net/mailman/listinfo/amradio > Post: AMRadio at mailman.qth.net > To unsubscribe, send an email to amradio-request at mailman.qth.net with > the word unsubscribe in the message body. > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to steinerviolinist at gmail.com -- http://oliversteiner.com From oldrotorheadsarge at outlook.com Mon Sep 26 16:50:04 2016 From: oldrotorheadsarge at outlook.com (Robert Bethman) Date: Mon, 26 Sep 2016 20:50:04 +0000 Subject: [AMRadio] FCC's AM power In-Reply-To: References: <644138908.3346178.1474598509954.ref@mail.yahoo.com> <644138908.3346178.1474598509954@mail.yahoo.com> <007501d216c1$a7406480$f5c12d80$@charter.net> <3FC974C690EA4152AC035A91C520E75A@garyPC> <005701d217a3$3c0a6cf0$b41f46d0$@charter.net> <9c534408-c1ef-7778-c45b-6ed3c37e0aad@gmail.com> Message-ID: Ollie and All, It doesn't matter whether it is an Autek or a Bird Peak reading meter. They simply read the Peak Power Output Power. I don't know a single watt meter that is capable of reading Peak Envelope Power. There is far too much circuitry involved in reading PEP. WE as a group of Amateurs don't have that sort of budget! I suspect an oscilloscope of beyond normal calibrated one would do so either. Even a darn good Tektronix Oscilloscope would be rather useless in an attempt to read PEP. Regards, Bob N0DGN -----Original Message----- From: AMRadio [mailto:amradio-bounces at mailman.qth.net] On Behalf Of Oliver Steiner Sent: Monday, September 26, 2016 4:19 PM To: Geoff Cc: amradio at mailman.qth.net Subject: Re: [AMRadio] FCC's AM power I'm not clear about the distinction between "peak power" and "peak envelope power" (If there is one). My Autek power/swr meter lets me select between average power and peak power, but am I monitoring peak *envelope* power when I have it switched to the "peak power" position? --- or is peak envelope power only possible to determine with a calibrated oscilloscope? I'm grateful to read your answers to this. Ollie W2QXR From garyschafer at largeriver.net Mon Sep 26 18:59:25 2016 From: garyschafer at largeriver.net (Gary Schafer) Date: Mon, 26 Sep 2016 17:59:25 -0500 Subject: [AMRadio] FCC's AM power In-Reply-To: References: <644138908.3346178.1474598509954.ref@mail.yahoo.com><644138908.3346178.1474598509954@mail.yahoo.com><007501d216c1$a7406480$f5c12d80$@charter.net><3FC974C690EA4152AC035A91C520E75A@garyPC><005701d217a3$3c0a6cf0$b41f46d0$@charter.net><9c534408-c1ef-7778-c45b-6ed3c37e0aad@gmail.com> Message-ID: Actually most watt meters that have a "peak power" position are intended to show PEP and not peak power. Some are better than others at doing so. Although most watt meters do detect peak power but are calibrated in average power. Peak envelope power is just a fast responding average power meter. Here is a wattmeter that is excellent at reading PEP. Yes it will read AM PEP accurately. http://www.telepostinc.com/lp100.html Price is around $465.00, not much different than a Bird and a couple of slugs. Note that true "peak power" is different than "Peak envelope power (PEP)". Peak power is measured from the actual peak voltage of the signal where as PEP is measured from the RMS voltage of the signal which gives us AVERAGE power (some incorrectly call this RMS power). With modulation PEP is the average RF power at the crest or peak of the modulation envelope. Easily seen on a scope. Peak envelope power and average power of a CW signal are the same. Think of the CW signal as a steady carrier, you find its power in the usual way and just call it average power. When keying the CW signal on and off you create an "envelope" for each character. The power at the crest or peak of this envelope is the peak envelope power, the same as if you were holding the key down. A voice signal creates this same kind of envelope with modulation. The only difference is the envelope varies up and down and slightly in frequency. For peak envelope power we are only concerned what the level of the maximum value of this peak. It is still an average power signal like the CW signal only varying in strength. Don't worry about being able to "catch" those illusive modulation peaks of a transient of some high modulation frequency. There are many RF cycles contained in any modulation envelope. For example a 7 MHZ RF signal has 7 million cycles per second. When modulated by say 7 KHZ modulation signal (probably a higher audio frequency than most would use) there will be 1000 cycles of RF contained in that one modulation envelope. The peak envelope power measurement is really done at an audio rate as far as variation of the signal. 73 Gary K4FMX > -----Original Message----- > From: AMRadio [mailto:amradio-bounces at mailman.qth.net] On Behalf Of > Robert Bethman > Sent: Monday, September 26, 2016 3:50 PM > To: amradio at mailman.qth.net > Subject: Re: [AMRadio] FCC's AM power > > Ollie and All, > > It doesn't matter whether it is an Autek or a Bird Peak reading meter. > > They simply read the Peak Power Output Power. > > I don't know a single watt meter that is capable of reading Peak > Envelope Power. > > There is far too much circuitry involved in reading PEP. WE as a group > of Amateurs don't have that sort of budget! > > I suspect an oscilloscope of beyond normal calibrated one would do so > either. > > Even a darn good Tektronix Oscilloscope would be rather useless in an > attempt to read PEP. > > Regards, Bob N0DGN > > -----Original Message----- > From: AMRadio [mailto:amradio-bounces at mailman.qth.net] On Behalf Of > Oliver Steiner > Sent: Monday, September 26, 2016 4:19 PM > To: Geoff > Cc: amradio at mailman.qth.net > Subject: Re: [AMRadio] FCC's AM power > > I'm not clear about the distinction between "peak power" and "peak > envelope power" (If there is one). My Autek power/swr meter lets me > select between average power and peak power, but am I monitoring peak > *envelope* power when I have it switched to the "peak power" position? > --- or is peak envelope power only possible to determine with a > calibrated oscilloscope? > > I'm grateful to read your answers to this. > > Ollie > W2QXR > ______________________________________________________________ > Our Main Website: http://www.amfone.net > AMRadio mailing list > Archives: http://mailman.qth.net/pipermail/amradio/ > List Rules (must read!): http://w5ami.net/amradiofaq.html > List Home: http://mailman.qth.net/mailman/listinfo/amradio > Post: AMRadio at mailman.qth.net > To unsubscribe, send an email to amradio-request at mailman.qth.net with > the word unsubscribe in the message body. > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to garyschafer at largeriver.net From ranchorobbo at gmail.com Mon Sep 26 21:47:42 2016 From: ranchorobbo at gmail.com (Rob Atkinson) Date: Mon, 26 Sep 2016 20:47:42 -0500 Subject: [AMRadio] FCC's AM power In-Reply-To: References: <644138908.3346178.1474598509954.ref@mail.yahoo.com> <644138908.3346178.1474598509954@mail.yahoo.com> <007501d216c1$a7406480$f5c12d80$@charter.net> <3FC974C690EA4152AC035A91C520E75A@garyPC> <005701d217a3$3c0a6cf0$b41f46d0$@charter.net> <9c534408-c1ef-7778-c45b-6ed3c37e0aad@gmail.com> Message-ID: Those meters that supposedly read PEP are almost like a scam. The reason is the meter isn't fast enough and even if they have some sort of battery powered "peak and hold" setting, that only captures a "peak" that may or may not be the "peaky peak super peak." Here a peak there a peak everywhere a peak peak Old Macdonald had a farm.... So then you try an audio sine wave from a sig. gen., but that doesn't represent a human voice. Which is why PEP is so ridiculous. Most AM operators who put any thought into this wind up speaking of their power in terms of carrier or input power and let it go at that if they mention it at all. It's the only meaningful power term. Previously I mentioned AM broadcast stations measure antenna current. They do this at an arranged time when there will be a dead carrier for at least 5 or 10 seconds so a reading can be made. They don't attempt any power calculation based on modulated current. 73 Rob K5UJ From donroden at hiwaay.net Mon Sep 26 22:59:48 2016 From: donroden at hiwaay.net (donroden at hiwaay.net) Date: Mon, 26 Sep 2016 21:59:48 -0500 Subject: [AMRadio] AM Power In-Reply-To: <000c01d21808$65d0bf70$31723e50$@charter.net> References: <006001d217a3$a4426b10$ecc74130$@charter.net> <8b795d6b-13c2-275a-4799-d002d6d263dc@gmail.com> <000c01d21808$65d0bf70$31723e50$@charter.net> Message-ID: <20160926215948.Horde.YRsFxrtCfM0XJlkS4OyY8YR@webmail.hiwaay.net> Its the newbie bureaucrats that scare me. Don W4DNR >> The newbies aren't our enemy. Ignorant bureaucrats, within our own ranks >> are the problem. From k9cox at charter.net Tue Sep 27 04:39:58 2016 From: k9cox at charter.net (Ross Stenberg) Date: Tue, 27 Sep 2016 03:39:58 -0500 Subject: [AMRadio] FCC's AM power In-Reply-To: References: <644138908.3346178.1474598509954.ref@mail.yahoo.com> <644138908.3346178.1474598509954@mail.yahoo.com> <007501d216c1$a7406480$f5c12d80$@charter.net> <3FC974C690EA4152AC035A91C520E75A@garyPC> <005701d217a3$3c0a6cf0$b41f46d0$@charter.net> <9c534408-c1ef-7778-c45b-6ed3c37e0aad@gmail.com> Message-ID: Why does any of this really matter when the metrics of watts in the real world is has such little meaning? dBm is meaningful, after all the difference between 1000 watts and 2000 watts is 3dB. 73 Ross K9COX From steinerviolinist at gmail.com Tue Sep 27 10:37:47 2016 From: steinerviolinist at gmail.com (Oliver Steiner) Date: Tue, 27 Sep 2016 10:37:47 -0400 Subject: [AMRadio] FCC's AM power In-Reply-To: References: <644138908.3346178.1474598509954.ref@mail.yahoo.com> <644138908.3346178.1474598509954@mail.yahoo.com> <007501d216c1$a7406480$f5c12d80$@charter.net> <3FC974C690EA4152AC035A91C520E75A@garyPC> <005701d217a3$3c0a6cf0$b41f46d0$@charter.net> <9c534408-c1ef-7778-c45b-6ed3c37e0aad@gmail.com> Message-ID: Does anyone know what instrument the FCC uses for measuring PEP during a visit to an amateur radio station? Ollie W2QXR On 9/27/16, Ross Stenberg wrote: > Why does any of this really matter when the metrics of watts in the real > world is has such little meaning? dBm is meaningful, after all the > difference between 1000 watts and 2000 watts is 3dB. > > 73 Ross K9COX > > > ______________________________________________________________ > Our Main Website: http://www.amfone.net > AMRadio mailing list > Archives: http://mailman.qth.net/pipermail/amradio/ > List Rules (must read!): http://w5ami.net/amradiofaq.html > List Home: http://mailman.qth.net/mailman/listinfo/amradio > Post: AMRadio at mailman.qth.net > To unsubscribe, send an email to amradio-request at mailman.qth.net with > the word unsubscribe in the message body. > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to steinerviolinist at gmail.com > -- http://oliversteiner.com From donroden at hiwaay.net Tue Sep 27 11:14:28 2016 From: donroden at hiwaay.net (donroden at hiwaay.net) Date: Tue, 27 Sep 2016 10:14:28 -0500 Subject: [AMRadio] FCC's AM power In-Reply-To: References: <644138908.3346178.1474598509954.ref@mail.yahoo.com> <644138908.3346178.1474598509954@mail.yahoo.com> <007501d216c1$a7406480$f5c12d80$@charter.net> <3FC974C690EA4152AC035A91C520E75A@garyPC> <005701d217a3$3c0a6cf0$b41f46d0$@charter.net> <9c534408-c1ef-7778-c45b-6ed3c37e0aad@gmail.com> Message-ID: <20160927101428.Horde.llw0siQ_JAiXWHyJIE4KjJO@webmail.hiwaay.net> And 3db represents only 1/2 of an S-unit at the other end... Hardly worth the extra effort, don't you think ? Don W4DNR Quoting Ross Stenberg : > Why does any of this really matter when the metrics of watts in the > real world is has such little meaning? dBm is meaningful, after all > the difference between 1000 watts and 2000 watts is 3dB. > > 73 Ross K9COX > > > ______________________________________________________________ > Our Main Website: http://www.amfone.net > AMRadio mailing list > Archives: http://mailman.qth.net/pipermail/amradio/ > List Rules (must read!): http://w5ami.net/amradiofaq.html > List Home: http://mailman.qth.net/mailman/listinfo/amradio > Post: AMRadio at mailman.qth.net > To unsubscribe, send an email to amradio-request at mailman.qth.net with > the word unsubscribe in the message body. > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to donroden at hiwaay.net From k4kyv at charter.net Tue Sep 27 12:08:27 2016 From: k4kyv at charter.net (Donald Chester) Date: Tue, 27 Sep 2016 11:08:27 -0500 Subject: [AMRadio] FCC's AM power In-Reply-To: References: <644138908.3346178.1474598509954.ref@mail.yahoo.com><644138908.3346178.1474598509954@mail.yahoo.com><007501d216c1$a7406480$f5c12d80$@charter.net><3FC974C690EA4152AC035A91C520E75A@garyPC><005701d217a3$3c0a6cf0$b41f46d0$@charter.net><9c534408-c1ef-7778-c45b-6ed3c37e0aad@gmail.com> Message-ID: <000401d218d9$61a7ea50$24f7bef0$@charter.net> > Gary Shafer wrote: > Actually most watt meters that have a "peak power" position are intended to > show PEP and not peak power. Some are better than others at doing so. > > Although most watt meters do detect peak power but are calibrated in > average power... > ...Note that true "peak power" is different than "Peak envelope power (PEP)". > Peak power is measured from the actual peak voltage of the signal where as > PEP is measured from the RMS voltage of the signal which gives us AVERAGE > power (some incorrectly call this RMS power). > With modulation PEP is the average RF power at the crest or peak of the > modulation envelope. Now how many of to-day's licensees, including Extra Class, do you think would read that and have even the slightest clue? > Although most watt meters do detect peak power but are calibrated in > average power. Peak envelope power is just a fast responding average > power meter. Very few instruments are capable of reading true average power. Average power = RMS voltage ? RMS current (there is NO SUCH THING as RMS power). Average voltage ? average current yields a meaningless figure. So-called "watt" meters actually read RF voltage or RF current, and, on the assumption of a defined resistive load (usually 50 ohms), the dial scale is calibrated for the number of watts that would be working into that load at that voltage reading. Diode rectifier meters like the Bird 43 read average voltage. It takes more sophisticated active circuitry to measure true RMS voltage. OTOH, a thermocouple RF ammeter is inherently a true RMS-reading device. The dial scale of the Bird 43 and similar meters are calibrated to indicate the average power of a steady unmodulated sinusoidal carrier into the prescribed resistive load, so they are useful for FM, CW, RTTY and other steady carrier modes with no amplitude modulation, since the average voltage of a sine wave is a known function of RMS voltage. (Vavg = 0.9 Vrms). The "average" power function of a Bird 43 falters when reading the power of a SSB transmitter. The meter reading will always be substantially lower than the true reading. With AM, the meter indicates average CARRIER power, but ignores sideband power. The reason for this is that the AVERAGE rectified RF voltage of an amplitude modulated carrier is the same as that of an unmodulated carrier; the positive peak and negative peak voltages cancel, leaving the meter to indicate the remainder, the carrier voltage. For a true average power indication, a square-law instrument (RMS voltage or RMS current reading) is required, since power is a function of voltage squared or current squared. OTOH, the thermocouple RF ammeter is inherently a square-law instrument that measures the actual heating effect of the current, which is, by definition, what RMS current is. An accurately calibrated diode rectifier type meter like the Bird 43 is useful for indicating AM carrier power, since the pointer does not kick up with modulation the way a thermocouple ammeter does. This will also reveal if carrier shift occurs with modulation. A rectifier type RF ammeter has an advantage when taking base-current readings at an AM broadcast, since the technician does not have to wait patiently for a few seconds pause in the program audio. A Bird 43 would unlikely be useful for this measurement, since few broadcast tower base impedances are precisely 50 +j0 ohms. > Here is a wattmeter that is excellent at reading PEP. Yes it will read AM PEP > accurately. > http://www.telepostinc.com/lp100.html Price is around $465.00, not much > different than a Bird and a couple of slugs. A better choice for that kind of money, according to Bird, the self-proclaimed "RF Experts", would be the APM-16, Average Reading Power Meter, which "is designed to keep pace with the ever growing complexity of digitally-based communication systems. Bird's model 43 and most other wattmeters available today were designed to measure power of CONSTANT AMPLITUDE, SINUSOIDAL WAVEFORMS. "Modern wireless communication systems can use a variety of digital techniques to combine many voice data channels into a complex, composite RF signal. Measurement of such signals with a conventional wattmeter may yield unacceptable errors. The APM-16 employs active circuitry to deliver accuracy of ? 5% for multiple-access technologies such as CDMA, TDMA, FDMA and other digitally-encoded communication systems. "Designed especially for RF power measurement in PCS, cellular, ESMR, paging and similar communication systems, EQUALLY EFFECTIVE for measuring RF power in CONVENTIONAL ANALOGUE SYSTEMS, uses APM-series plug-in elements to cover a wide range of frequency and power levels. Simple Thruline? style operation for instant forward or reflected power readings." http://www.birdrf.com/Products/Wattmeters_Line%20Sections/PortableWattmeters /APM-16_Average-Reading-Power-Meter.aspx A true direct-reading RF power meter would have four terminals, one pair in series with the load and another pair bridged across the load, to sample RF current and RF voltage. It would still be accurate only when working into a purely resistive, non-reactive load, unless it contained built-in circuitry to correct for power factor. Such instruments exist for 60~ a.c., but I'm not sure about RF. Don k4kyv From k4kyv at charter.net Tue Sep 27 12:15:10 2016 From: k4kyv at charter.net (Donald Chester) Date: Tue, 27 Sep 2016 11:15:10 -0500 Subject: [AMRadio] FCC's AM power References: <644138908.3346178.1474598509954.ref@mail.yahoo.com> <644138908.3346178.1474598509954@mail.yahoo.com> <007501d216c1$a7406480$f5c12d80$@charter.net> <3FC974C690EA4152AC035A91C520E75A@garyPC> Message-ID: <000601d218da$5226fe30$f674fa90$@charter.net> PS: Don't forget to copy and paste the above link in its entirety into your browser. This list will probably truncate the URL and render it non-functional. From garyschafer at largeriver.net Tue Sep 27 13:11:19 2016 From: garyschafer at largeriver.net (Gary Schafer) Date: Tue, 27 Sep 2016 12:11:19 -0500 Subject: [AMRadio] FCC's AM power In-Reply-To: <000401d218d9$61a7ea50$24f7bef0$@charter.net> References: <644138908.3346178.1474598509954.ref@mail.yahoo.com><644138908.3346178.1474598509954@mail.yahoo.com><007501d216c1$a7406480$f5c12d80$@charter.net><3FC974C690EA4152AC035A91C520E75A@garyPC><005701d217a3$3c0a6cf0$b41f46d0$@charter.net><9c534408-c1ef-7778-c45b-6ed3c37e0aad@gmail.com> <000401d218d9$61a7ea50$24f7bef0$@charter.net> Message-ID: The Bird APM-16 is about 3 times the price of the Telepost unit and you still have to buy slugs at close to $300.00 apiece for the Bird unit. Measuring power with a directional coupler is common practice. Even the Bird 43 uses a directional coupler and it measures forward current and voltage as well as reflected current and voltage. It uses a diode as a peak detector, calibrated in average power. The line impedance does not have to be exactly 50 ohms in order to have accurate measurements same as other watt meters using a directional coupler. 73 Gary K4FMX > -----Original Message----- > From: AMRadio [mailto:amradio-bounces at mailman.qth.net] On Behalf Of > Donald Chester > Sent: Tuesday, September 27, 2016 11:08 AM > To: amradio at mailman.qth.net > Subject: Re: [AMRadio] FCC's AM power > > > Gary Shafer wrote: > > > Actually most watt meters that have a "peak power" position are > intended > to > > show PEP and not peak power. Some are better than others at doing so. > > > > Although most watt meters do detect peak power but are calibrated in > > average power... > > > ...Note that true "peak power" is different than "Peak envelope power > (PEP)". > > Peak power is measured from the actual peak voltage of the signal > where as > > PEP is measured from the RMS voltage of the signal which gives us > AVERAGE > > power (some incorrectly call this RMS power). > > With modulation PEP is the average RF power at the crest or peak of > the > > modulation envelope. > > Now how many of to-day's licensees, including Extra Class, do you think > would read that and have even the slightest clue? > > > Although most watt meters do detect peak power but are calibrated in > > average power. Peak envelope power is just a fast responding average > > power meter. > > Very few instruments are capable of reading true average power. Average > power = RMS voltage ? RMS current (there is NO SUCH THING as RMS > power). > Average voltage ? average current yields a meaningless figure. So-called > "watt" meters actually read RF voltage or RF current, and, on the > assumption > of a defined resistive load (usually 50 ohms), the dial scale is > calibrated > for the number of watts that would be working into that load at that > voltage > reading. Diode rectifier meters like the Bird 43 read average voltage. > It > takes more sophisticated active circuitry to measure true RMS voltage. > OTOH, a thermocouple RF ammeter is inherently a true RMS-reading device. > The dial scale of the Bird 43 and similar meters are calibrated to > indicate > the average power of a steady unmodulated sinusoidal carrier into the > prescribed resistive load, so they are useful for FM, CW, RTTY and other > steady carrier modes with no amplitude modulation, since the average > voltage > of a sine wave is a known function of RMS voltage. (Vavg = 0.9 Vrms). > > The "average" power function of a Bird 43 falters when reading the power > of > a SSB transmitter. The meter reading will always be substantially lower > than the true reading. With AM, the meter indicates average CARRIER > power, > but ignores sideband power. The reason for this is that the AVERAGE > rectified RF voltage of an amplitude modulated carrier is the same as > that > of an unmodulated carrier; the positive peak and negative peak voltages > cancel, leaving the meter to indicate the remainder, the carrier > voltage. > For a true average power indication, a square-law instrument (RMS > voltage or > RMS current reading) is required, since power is a function of voltage > squared or current squared. OTOH, the thermocouple RF ammeter is > inherently > a square-law instrument that measures the actual heating effect of the > current, which is, by definition, what RMS current is. > > An accurately calibrated diode rectifier type meter like the Bird 43 is > useful for indicating AM carrier power, since the pointer does not kick > up > with modulation the way a thermocouple ammeter does. This will also > reveal > if carrier shift occurs with modulation. A rectifier type RF ammeter has > an > advantage when taking base-current readings at an AM broadcast, since > the > technician does not have to wait patiently for a few seconds pause in > the > program audio. A Bird 43 would unlikely be useful for this measurement, > since few broadcast tower base impedances are precisely 50 +j0 ohms. > > > > Here is a wattmeter that is excellent at reading PEP. Yes it will read > AM > PEP > > accurately. > > http://www.telepostinc.com/lp100.html Price is around $465.00, not > much > > different than a Bird and a couple of slugs. > > > A better choice for that kind of money, according to Bird, the > self-proclaimed "RF Experts", would be the APM-16, Average Reading Power > Meter, which "is designed to keep pace with the ever growing complexity > of > digitally-based communication systems. Bird's model 43 and most other > wattmeters available today were designed to measure power of CONSTANT > AMPLITUDE, SINUSOIDAL WAVEFORMS. > > "Modern wireless communication systems can use a variety of digital > techniques to combine many voice data channels into a complex, composite > RF > signal. Measurement of such signals with a conventional wattmeter may > yield > unacceptable errors. The APM-16 employs active circuitry to deliver > accuracy > of ? 5% for multiple-access technologies such as CDMA, TDMA, FDMA and > other > digitally-encoded communication systems. > > "Designed especially for RF power measurement in PCS, cellular, ESMR, > paging > and similar communication systems, EQUALLY EFFECTIVE for measuring RF > power > in CONVENTIONAL ANALOGUE SYSTEMS, uses APM-series plug-in elements to > cover > a wide range of frequency and power levels. Simple Thruline? style > operation > for instant forward or reflected power readings." > > http://www.birdrf.com/Products/Wattmeters_Line%20Sections/PortableWattme > ters > /APM-16_Average-Reading-Power-Meter.aspx > > > A true direct-reading RF power meter would have four terminals, one pair > in > series with the load and another pair bridged across the load, to sample > RF > current and RF voltage. It would still be accurate only when working > into a > purely resistive, non-reactive load, unless it contained built-in > circuitry > to correct for power factor. Such instruments exist for 60~ a.c., but > I'm > not sure about RF. > > Don k4kyv > > From oldrotorheadsarge at outlook.com Tue Sep 27 13:42:01 2016 From: oldrotorheadsarge at outlook.com (Robert Bethman) Date: Tue, 27 Sep 2016 17:42:01 +0000 Subject: [AMRadio] FCC's AM power In-Reply-To: References: <644138908.3346178.1474598509954.ref@mail.yahoo.com><644138908.3346178.1474598509954@mail.yahoo.com><007501d216c1$a7406480$f5c12d80$@charter.net><3FC974C690EA4152AC035A91C520E75A@garyPC><005701d217a3$3c0a6cf0$b41f46d0$@charter.net><9c534408-c1ef-7778-c45b-6ed3c37e0aad@gmail.com> <000401d218d9$61a7ea50$24f7bef0$@charter.net> Message-ID: I happen to use the Bird 43P. It does read peaks. As with any other "Peak" reading device, it does NOT keep up with the peaks! The only way to obtain peaks with these devices, is to use CW as the mode to read the Peak Power Level. I have been threatening to place an internal thermocouple ammeter in line with the output. I do in fact have at least one or two around. They came out of the BC-939 Antenna Coupler. It is mis-labelled as an antenna tuner! Regards, Bob - N0DGN -----Original Message----- From: AMRadio [mailto:amradio-bounces at mailman.qth.net] On Behalf Of Gary Schafer Sent: Tuesday, September 27, 2016 1:11 PM To: 'Donald Chester' ; amradio at mailman.qth.net Subject: Re: [AMRadio] FCC's AM power The Bird APM-16 is about 3 times the price of the Telepost unit and you still have to buy slugs at close to $300.00 apiece for the Bird unit. Measuring power with a directional coupler is common practice. Even the Bird 43 uses a directional coupler and it measures forward current and voltage as well as reflected current and voltage. It uses a diode as a peak detector, calibrated in average power. The line impedance does not have to be exactly 50 ohms in order to have accurate measurements same as other watt meters using a directional coupler. 73 Gary K4FMX > A better choice for that kind of money, according to Bird, the > self-proclaimed "RF Experts", would be the APM-16, Average Reading > Power Meter, which "is designed to keep pace with the ever growing > complexity of digitally-based communication systems. Bird's model 43 > and most other wattmeters available today were designed to measure > power of CONSTANT AMPLITUDE, SINUSOIDAL WAVEFORMS. > > "Modern wireless communication systems can use a variety of digital > techniques to combine many voice data channels into a complex, > composite RF signal. Measurement of such signals with a conventional > wattmeter may yield unacceptable errors. The APM-16 employs active > circuitry to deliver accuracy of ? 5% for multiple-access technologies > such as CDMA, TDMA, FDMA and other digitally-encoded communication > systems. > > "Designed especially for RF power measurement in PCS, cellular, ESMR, > paging and similar communication systems, EQUALLY EFFECTIVE for > measuring RF power in CONVENTIONAL ANALOGUE SYSTEMS, uses APM-series > plug-in elements to cover a wide range of frequency and power levels. > Simple Thruline? style operation for instant forward or reflected > power readings." > > http://www.birdrf.com/Products/Wattmeters_Line%20Sections/PortableWatt > me > ters > /APM-16_Average-Reading-Power-Meter.aspx > > > A true direct-reading RF power meter would have four terminals, one > pair in series with the load and another pair bridged across the load, > to sample RF current and RF voltage. It would still be accurate only > when working into a purely resistive, non-reactive load, unless it > contained built-in circuitry to correct for power factor. Such > instruments exist for 60~ a.c., but I'm not sure about RF. > > Don k4kyv > > ______________________________________________________________ Our Main Website: http://www.amfone.net AMRadio mailing list Archives: http://mailman.qth.net/pipermail/amradio/ List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Post: AMRadio at mailman.qth.net To unsubscribe, send an email to amradio-request at mailman.qth.net with the word unsubscribe in the message body. This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to oldrotorheadsarge at outlook.com From w5jo at brightok.net Tue Sep 27 15:27:06 2016 From: w5jo at brightok.net (w5jo at brightok.net) Date: Tue, 27 Sep 2016 14:27:06 -0500 Subject: [AMRadio] FCC's AM power In-Reply-To: References: <644138908.3346178.1474598509954.ref@mail.yahoo.com><644138908.3346178.1474598509954@mail.yahoo.com><007501d216c1$a7406480$f5c12d80$@charter.net><3FC974C690EA4152AC035A91C520E75A@garyPC><005701d217a3$3c0a6cf0$b41f46d0$@charter.net><9c534408-c1ef-7778-c45b-6ed3c37e0aad@gmail.com><000401d218d9$61a7ea50$24f7bef0$@charter.net> Message-ID: <41D4ECA3166A49F890BC5787309D6232@JimPC> Bird made a "peak" reading meter that used a slug for 2-30 megacycles, and other slugs were made for various large segments of the bands along with a variable switch that changed the power level of the meter. I can't recall for sure but think the one I had was the 4311. It was powered by AC and had a 9 volt battery for portable use. I saw one of them before I saw the peak reading 43P kit to add to the 43. The instruction book that accompanied the meter had a formula for calculating the true peak of the signal as the meter would not indicate it. Another peak reading meter they made was the 4314 which was a variation of it. Advertising for these meters said they would read the "Peak" power of an AM signal but I don't see how that is possible. I sold my example of the 4311 some years back and the manual went with it so I don't have specifics. Maybe someone has a manual and can provide specifics. I sold the meter for about $650 with the one slug. It was a special slug to cover that much of the band, but was the classic Bird design with a diode in the slug. If I recall correctly they claimed 5% at full scale for accuracy in a steady carrier but provided that formula for calculating the "true peak" . I wonder if the documentation that accompanies the 43P has a formula or do they claim it to be accurate? But as Gary said the Telepost unit does a better job for much less. Jim W5JO -----Original Message----- I happen to use the Bird 43P. It does read peaks. As with any other "Peak" reading device, it does NOT keep up with the peaks! The only way to obtain peaks with these devices, is to use CW as the mode to read the Peak Power Level. I have been threatening to place an internal thermocouple ammeter in line with the output. I do in fact have at least one or two around. They came out of the BC-939 Antenna Coupler. It is mis-labelled as an antenna tuner! Regards, Bob - N0DGN -----Original Message----- The Bird APM-16 is about 3 times the price of the Telepost unit and you still have to buy slugs at close to $300.00 apiece for the Bird unit. Measuring power with a directional coupler is common practice. Even the Bird 43 uses a directional coupler and it measures forward current and voltage as well as reflected current and voltage. It uses a diode as a peak detector, calibrated in average power. The line impedance does not have to be exactly 50 ohms in order to have accurate measurements same as other watt meters using a directional coupler. 73 From garyschafer at largeriver.net Tue Sep 27 16:10:51 2016 From: garyschafer at largeriver.net (Gary Schafer) Date: Tue, 27 Sep 2016 15:10:51 -0500 Subject: [AMRadio] FCC's AM power In-Reply-To: <41D4ECA3166A49F890BC5787309D6232@JimPC> References: <644138908.3346178.1474598509954.ref@mail.yahoo.com><644138908.3346178.1474598509954@mail.yahoo.com><007501d216c1$a7406480$f5c12d80$@charter.net><3FC974C690EA4152AC035A91C520E75A@garyPC><005701d217a3$3c0a6cf0$b41f46d0$@charter.net><9c534408-c1ef-7778-c45b-6ed3c37e0aad@gmail.com><000401d218d9$61a7ea50$24f7bef0$@charter.net> <41D4ECA3166A49F890BC5787309D6232@JimPC> Message-ID: <632F364D51164B0EA045560D2CC16FB6@garyPC> Hi Jim, The manual for the 4311 is here: http://www.birdrf.com/Resources/DiscontinuedProducts/BEC-UserManuals.aspx#.V -rNifkrLcc I think the calculation that you were referring to was to find the % modulation of an AM signal by the power readings. 73 Gary K4FMX > -----Original Message----- > From: AMRadio [mailto:amradio-bounces at mailman.qth.net] On Behalf Of > w5jo at brightok.net > Sent: Tuesday, September 27, 2016 2:27 PM > To: amradio at mailman.qth.net > Subject: Re: [AMRadio] FCC's AM power > > Bird made a "peak" reading meter that used a slug for 2-30 megacycles, > and > other slugs were made for various large segments of the bands along with > a > variable switch that changed the power level of the meter. > > I can't recall for sure but think the one I had was the 4311. It was > powered by AC and had a 9 volt battery for portable use. I saw one of > them before I saw the peak reading 43P kit to add to the 43. The > instruction book that accompanied the meter had a formula for > calculating > the true peak of the signal as the meter would not indicate it. > > Another peak reading meter they made was the 4314 which was a variation > of > it. Advertising for these meters said they would read the "Peak" power > of > an AM signal but I don't see how that is possible. I sold my example of > the > 4311 some years back and the manual went with it so I don't have > specifics. > Maybe someone has a manual and can provide specifics. > > I sold the meter for about $650 with the one slug. It was a special > slug to > cover that much of the band, but was the classic Bird design with a > diode in > the slug. If I recall correctly they claimed 5% at full scale for > accuracy > in a steady carrier but provided that formula for calculating the "true > peak" . I wonder if the documentation that accompanies the 43P has a > formula or do they claim it to be accurate? > > But as Gary said the Telepost unit does a better job for much less. > > Jim > W5JO > > -----Original Message----- > > > I happen to use the Bird 43P. It does read peaks. As with any other > "Peak" > reading device, it does NOT keep up with the peaks! The only way to > obtain > peaks with these devices, is to use CW as the mode to read the Peak > Power > Level. > > I have been threatening to place an internal thermocouple ammeter in > line > with the output. > I do in fact have at least one or two around. They came out of the BC- > 939 > Antenna Coupler. It is mis-labelled as an antenna tuner! > > Regards, Bob - N0DGN > > -----Original Message----- > The Bird APM-16 is about 3 times the price of the Telepost unit and you > still have to buy slugs at close to $300.00 apiece for the Bird unit. > > Measuring power with a directional coupler is common practice. Even the > Bird > 43 uses a directional coupler and it measures forward current and > voltage as > well as reflected current and voltage. > It uses a diode as a peak detector, calibrated in average power. The > line > impedance does not have to be exactly 50 ohms in order to have accurate > measurements same as other watt meters using a directional coupler. > > 73 > > ______________________________________________________________ > Our Main Website: http://www.amfone.net > AMRadio mailing list > Archives: http://mailman.qth.net/pipermail/amradio/ > List Rules (must read!): http://w5ami.net/amradiofaq.html > List Home: http://mailman.qth.net/mailman/listinfo/amradio > Post: AMRadio at mailman.qth.net > To unsubscribe, send an email to amradio-request at mailman.qth.net with > the word unsubscribe in the message body. > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to garyschafer at largeriver.net From k4kyv at charter.net Tue Sep 27 20:13:23 2016 From: k4kyv at charter.net (Donald Chester) Date: Tue, 27 Sep 2016 19:13:23 -0500 Subject: [AMRadio] FCC's AM power In-Reply-To: <41D4ECA3166A49F890BC5787309D6232@JimPC> References: <644138908.3346178.1474598509954.ref@mail.yahoo.com><644138908.3346178.1474598509954@mail.yahoo.com><007501d216c1$a7406480$f5c12d80$@charter.net><3FC974C690EA4152AC035A91C520E75A@garyPC><005701d217a3$3c0a6cf0$b41f46d0$@charter.net><9c534408-c1ef-7778-c45b-6ed3c37e0aad@gmail.com><000401d218d9$61a7ea50$24f7bef0$@charter.net> <41D4ECA3166A49F890BC5787309D6232@JimPC> Message-ID: <000101d2191d$20c39400$624abc00$@charter.net> > I sold the meter for about $650 with the one slug. It was a special slug to > cover that much of the band, but was the classic Bird design with a diode in > the slug. If I recall correctly they claimed 5% at full scale for accuracy > in a steady carrier but provided that formula for calculating the "true peak" That P.E.P. bull -Shi'ite isn't worth that kind of money to me. I don't remember ever paying that much for one single piece of amateur radio equipment in my entire life, except for my tower and radial ground system, and I have some pretty top-of-the-line stuff in my shack. Besides, that pricey meter would be worthless here; not a sprig of co-ass, 50 ohms or otherwise, in my entire antenna system. Don k4kyv From w5jo at brightok.net Tue Sep 27 21:29:43 2016 From: w5jo at brightok.net (w5jo at brightok.net) Date: Tue, 27 Sep 2016 20:29:43 -0500 Subject: [AMRadio] FCC's AM power In-Reply-To: <000101d2191d$20c39400$624abc00$@charter.net> References: <644138908.3346178.1474598509954.ref@mail.yahoo.com><644138908.3346178.1474598509954@mail.yahoo.com><007501d216c1$a7406480$f5c12d80$@charter.net><3FC974C690EA4152AC035A91C520E75A@garyPC><005701d217a3$3c0a6cf0$b41f46d0$@charter.net><9c534408-c1ef-7778-c45b-6ed3c37e0aad@gmail.com><000401d218d9$61a7ea50$24f7bef0$@charter.net> <41D4ECA3166A49F890BC5787309D6232@JimPC> <000101d2191d$20c39400$624abc00$@charter.net> Message-ID: <59347D40988448AFA1AD501D92363DD7@JimPC> I sold it because it did not provide any help with SSB, which I operate from time to time, and any model 43 would do for steady state carrier. However there are many people willing to pay big bucks for things like that so I cashed in. For many years I used an RF ammeter and oscilloscope for power and modulation. I have now quit both because I operate below the max power and modulation percentage allowed. Jim W5JO -----Original Message----- That P.E.P. bull -Shi'ite isn't worth that kind of money to me. I don't remember ever paying that much for one single piece of amateur radio equipment in my entire life, except for my tower and radial ground system, and I have some pretty top-of-the-line stuff in my shack. Besides, that pricey meter would be worthless here; not a sprig of co-ass, 50 ohms or otherwise, in my entire antenna system. Don k4kyv From k4kyv at charter.net Wed Sep 28 04:27:55 2016 From: k4kyv at charter.net (Donald Chester) Date: Wed, 28 Sep 2016 03:27:55 -0500 Subject: [AMRadio] FCC's AM power In-Reply-To: <59347D40988448AFA1AD501D92363DD7@JimPC> References: <644138908.3346178.1474598509954.ref@mail.yahoo.com><644138908.3346178.1474598509954@mail.yahoo.com><007501d216c1$a7406480$f5c12d80$@charter.net><3FC974C690EA4152AC035A91C520E75A@garyPC><005701d217a3$3c0a6cf0$b41f46d0$@charter.net><9c534408-c1ef-7778-c45b-6ed3c37e0aad@gmail.com><000401d218d9$61a7ea50$24f7bef0$@charter.net> <41D4ECA3166A49F890BC5787309D6232@JimPC> <000101d2191d$20c39400$624abc00$@charter.net> <59347D40988448AFA1AD501D92363DD7@JimPC> Message-ID: <000301d21962$3670b090$a35211b0$@charter.net> > For many years I used an RF ammeter and oscilloscope for power and > modulation. I have now quit both because I operate below the max power > and modulation percentage allowed. > > Jim W5JO There is no longer a limit to modulation percentage. The FCC deleted the former rule that prohibited amplitude modulation in excess of 100%, back in the late70s. They probably thought the rule was extraneous, believing or hoping that amateur AM would soon die out, or that the FCC would outlaw it. That was the same proceeding in which they also deleted the former rule against simultaneous amplitude and frequency modulation, making Timtron's "SBE" perfectly legal. Don k4kyv From ranchorobbo at gmail.com Wed Sep 28 06:00:45 2016 From: ranchorobbo at gmail.com (Rob Atkinson) Date: Wed, 28 Sep 2016 05:00:45 -0500 Subject: [AMRadio] FCC's AM power In-Reply-To: <632F364D51164B0EA045560D2CC16FB6@garyPC> References: <644138908.3346178.1474598509954.ref@mail.yahoo.com> <644138908.3346178.1474598509954@mail.yahoo.com> <007501d216c1$a7406480$f5c12d80$@charter.net> <3FC974C690EA4152AC035A91C520E75A@garyPC> <005701d217a3$3c0a6cf0$b41f46d0$@charter.net> <9c534408-c1ef-7778-c45b-6ed3c37e0aad@gmail.com> <000401d218d9$61a7ea50$24f7bef0$@charter.net> <41D4ECA3166A49F890BC5787309D6232@JimPC> <632F364D51164B0EA045560D2CC16FB6@garyPC> Message-ID: I have a Bird 43 with the add on circuit for the peak reading function with the 9 v. battery inside. Not long after I got it (at a hamfest) I removed the battery and put it back into regular Bird 43 mode because I thought the peak reading thing was a waste of time and I didn't want to forget about the battery and find it having leaked all over 10 years or more later on. I also measure power when I need to, with RF amp meters into known measured resistances. But RF amp meters are not always accurate. The more you get into power measurement the more you realize you are chasing an illusion if you are trying to get some exact measurement. Unless you have costly scientific lab apparatus you mostly have to take readings from a few sources and average them to get the best approximation. Nowadays my concern with output power is limited to guestimating the efficiency of the final PA. 73 Rob K5UJ From jcandela at prodigy.net Wed Sep 28 07:45:31 2016 From: jcandela at prodigy.net (Jim Candela) Date: Wed, 28 Sep 2016 11:45:31 +0000 (UTC) Subject: [AMRadio] FCC's AM power In-Reply-To: References: <644138908.3346178.1474598509954.ref@mail.yahoo.com> <644138908.3346178.1474598509954@mail.yahoo.com> <007501d216c1$a7406480$f5c12d80$@charter.net> <3FC974C690EA4152AC035A91C520E75A@garyPC> <005701d217a3$3c0a6cf0$b41f46d0$@charter.net> <9c534408-c1ef-7778-c45b-6ed3c37e0aad@gmail.com> <000401d218d9$61a7ea50$24f7bef0$@charter.net> <41D4ECA3166A49F890BC5787309D6232@JimPC> <632F364D51164B0EA045560D2CC16FB6@garyPC> Message-ID: <136217992.192316.1475063131872@mail.yahoo.com> As a Novice back in the early 70's I was always thinking that if I dipped the final at > 75 watts DC input, I'd have a knock on the door from the FCC, and they'd confiscate my equipment and then arrest me. Looking at the issue today, it seems to me that a few DB in power to the antenna is offset with the variability of propagation which is in the 10's of DB; maybe 50 db on 75m between 5 PM and 8 PM. Therefore whether you are running 250 watts or 750 watts AM, the resultant difference is hardly noticeable unless your signal at the lower power is being received at the receiver threshold. With the advancement of SDR receivers, one can tell at a glance relative signal strength, and spectrum purity over the frequency width of the pan Adapter display. The guys causing trouble are the ones that have a dirty signal which spread out both sides of the center frequency due to harmonic distortion and intermodulation distortion products. A 100 watt rig over driven can cause far more harm than a clean rig running greater than the legal limit. I am always amazed when I see Don K4KYV on my SDR Pan Adapter. Don is often one of the stronger signals seen on the band, and although strong, his AM signal is very clean...in fact, narrower than many SSB signals seen on the band. The main reason he is strong is because of his antenna and radial system. To conclude, if your are running QRO, have a nice clean signal, and you will do little harm to the adjacent signals on the band. By clean, limit the audio bandwidth to something like 3.8 Khz, but more importantly, make sure the audio/RF chain are not overdriven. Relying on ALC from a linear back to the exciter is pretty much a guarantee transmitting a broad signal. The ALC during the attack time constant cannot throttle back the exciter fast enough. JimWd5JKO On Wednesday, September 28, 2016 5:01 AM, Rob Atkinson wrote: I have a Bird 43 with the add on circuit for the peak reading function with the 9 v. battery inside.? Not long after I got it (at a hamfest) I removed the battery and put it back into regular Bird 43 mode because I thought the peak reading thing was a waste of time and I didn't want to forget about the battery and find it having leaked all over 10 years or more later on. I also measure power when I need to, with RF amp meters into known measured resistances.? But RF amp meters are not always accurate. The more you get into power measurement the more you realize you are chasing an illusion if you are trying to get some exact measurement. Unless you have costly scientific lab apparatus you mostly have to take readings from a few sources and average them to get the best approximation.? Nowadays my concern with output power is limited to guestimating the efficiency of the final PA. 73 Rob K5UJ ______________________________________________________________ Our Main Website: http://www.amfone.net AMRadio mailing list Archives: http://mailman.qth.net/pipermail/amradio/ List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Post: AMRadio at mailman.qth.net To unsubscribe, send an email to amradio-request at mailman.qth.net with the word unsubscribe in the message body. This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to jcandela at prodigy.net From ranickel at comcast.net Wed Sep 28 13:15:23 2016 From: ranickel at comcast.net (Robert Nickels) Date: Wed, 28 Sep 2016 12:15:23 -0500 Subject: [AMRadio] Taylor tubes Message-ID: <31cf95cc-266b-eeb3-3d7b-2454fa03b0d7@comcast.net> A buddy gave me some old tubes when he was moving and in the bunch was a Taylor tube 866 rectifier box. Not real interesting - until I looked at what was inside - a brand new Taylor T-20! Now this deserves to be used in a transmitter - any suggestions of where to look would be appreciated as I haven't even started to search yet but it's such a thing of beauty it should be used in a classic line-up. There was also what we'd call an "RMA Form" from Taylor Tubes -just a little piece of nostalgia I though others might enjoy taking a look at: http://i.imgur.com/R4AOYVY.jpg They asked for a lot of information but it sounds like they also stood behind their product, event to the point of "adjusting" the value of a failed thoriated filament tube. Another thing in that box were four 872A mercury vapor rectifiers - the big brother to the 866, made by GE and new in their JAN boxes. Anyone having a legitimate use for them should drop me a line (i.e. not just breaking them open to get the mercury ;-)) Free for the shipping cost. 73, Bob W9RAN From jc at pctechref.com Wed Sep 28 13:38:33 2016 From: jc at pctechref.com (John Coleman) Date: Wed, 28 Sep 2016 12:38:33 -0500 Subject: [AMRadio] FCC's AM power In-Reply-To: References: <644138908.3346178.1474598509954.ref@mail.yahoo.com> <644138908.3346178.1474598509954@mail.yahoo.com> <007501d216c1$a7406480$f5c12d80$@charter.net> <3FC974C690EA4152AC035A91C520E75A@garyPC> <005701d217a3$3c0a6cf0$b41f46d0$@charter.net> <9c534408-c1ef-7778-c45b-6ed3c37e0aad@gmail.com> Message-ID: <001801d219af$229a1460$67ce3d20$@pctechref.com> Power definitions can be very confusing. And as many have said " It don't really matter anyway for a number of reasons". A lot of the stuff below is for new comers so pardon the length. It was all very confusing to me durring my high school years and several years after. Power, when determind at the peak of any wave by the peak voltage and peak current, is relitively useless, in my humble opinion. It is posisble to have a peak power calculated at 1000 watts, but only be able to light a #47 lamp. Power is a measurment of the amount of work done or capable of doing. When you look at the light of a 100 watt, 115 volt lamp running on 115 volts DC and measure the current it is found to be just under 1 amp (100/115) If you measure the peak voltage when the lamp is running on AC you will find the peak voltage to be about 160 volts. and the peak current to be just under 1.6 amps. This is almost 250 watts but not really because it is not there all the time only on peaks and constantly changing. Yet the lamp gives off the same heat and light as it did when running on DC. So to find the the average power from the AC source, we must use the RMS values of voltage and current. RMS voltage would be about 115 volts and the RMS current would be the same as the DC current (100w/115v). (BTW - Most AC volt meters are fixed to measure RMS values of a sine wave only, not peak, and not any other wave shape.) The same is true when meassuring RF. If you had a metering device that measured the RF peak voltage across a 50 ohm dummy load with a carrier wave only, then to find the power you would multiple .707 time the measured peak voltage to get the RMS value, square that value and divide by 50 (Erms * Erms) / 50. The same measurement and calulation would be true when measuring an AM wave. But the measuring device would need to have the capability to measure the peak voltage and and hold the measurement while you read it. A scope will give you a close idea if using a audio signal generator for input regardless of wave form as long as it is repeditive. This is why many hams speak the word "four" into the microphone so as to get some simbalence of a repatative wave form. But there are voltmeters that will measure the peak voltage with modulation and not change for a while so that you can read it. Another way to look at it is to imagine a XMTR whose power is varying by a knob and some one is turning the knob back and forth. The output power is varing along with the knob. on a slow sweep scope it would look like an AM signal with very low freq modulation depending on the speed the knob is turned up and down. The peak envelope power is the power (Erms * Erms/50ohms) at the time the knob is at its max. I made a peak reading voltmeter adapter once using a 6AL5 tube and connected one plate to the dummy load terminal and the coresponding cathode to a .05uf capacitor of which the oposite end was grounded to the dummy load ground. Measured the voltage across the capacitor with VTVM and found the the discharge time for the .05 cap was very slow and was able to make very acurate measurments. The Capacitor charges to the peak of the RF voltage but discharges very slow having only the VTVM as a bleader. I built it into the top box on the heath cantenna. and lit up the 6AL5 with a 6 volt latern battery so I could move it around with out having to plug in a filiment XFMR. I think the regulation reads something like this. "The Power of a single sine wave (360 deg) RF at the peak of the modulation envelope" The mesurment and calculations above should satisfy this statement. Hope this clears up some stuff. 73 , John, WA5BXO From ranchorobbo at gmail.com Wed Sep 28 15:31:44 2016 From: ranchorobbo at gmail.com (Rob Atkinson) Date: Wed, 28 Sep 2016 14:31:44 -0500 Subject: [AMRadio] Taylor tubes In-Reply-To: <31cf95cc-266b-eeb3-3d7b-2454fa03b0d7@comcast.net> References: <31cf95cc-266b-eeb3-3d7b-2454fa03b0d7@comcast.net> Message-ID: Hi Bob, for the T-20 I'd start by looking in any handbooks from the 1930s and transformer manufacturer catalogs and flyers. Too bad you don't have a second T-20 because I think the circuits frequently were push pull finals. Keep the 872As vertical as much as possible. Rob K5UJ On Wed, Sep 28, 2016 at 12:15 PM, Robert Nickels wrote: > A buddy gave me some old tubes when he was moving and in the bunch was a > Taylor tube 866 rectifier box. Not real interesting - until I looked at > what was inside - a brand new Taylor T-20! Now this deserves to be used in a > transmitter - any suggestions of where to look would be appreciated as I > haven't even started to search yet but it's such a thing of beauty it should > be used in a classic line-up. > > There was also what we'd call an "RMA Form" from Taylor Tubes -just a little > piece of nostalgia I though others might enjoy taking a look at: > > http://i.imgur.com/R4AOYVY.jpg > > They asked for a lot of information but it sounds like they also stood > behind their product, event to the point of "adjusting" the value of a > failed thoriated filament tube. > > Another thing in that box were four 872A mercury vapor rectifiers - the big > brother to the 866, made by GE and new in their JAN boxes. Anyone having a > legitimate use for them should drop me a line (i.e. not just breaking them > open to get the mercury ;-)) Free for the shipping cost. > > 73, Bob W9RAN > From k4kyv at charter.net Thu Sep 29 13:04:10 2016 From: k4kyv at charter.net (Donald Chester) Date: Thu, 29 Sep 2016 12:04:10 -0500 Subject: [AMRadio] FCC's AM power In-Reply-To: <001801d219af$229a1460$67ce3d20$@pctechref.com> References: <644138908.3346178.1474598509954.ref@mail.yahoo.com> <644138908.3346178.1474598509954@mail.yahoo.com> <007501d216c1$a7406480$f5c12d80$@charter.net> <3FC974C690EA4152AC035A91C520E75A@garyPC> <005701d217a3$3c0a6cf0$b41f46d0$@charter.net> <9c534408-c1ef-7778-c45b-6ed3c37e0aad@gmail.com> <001801d219af$229a1460$67ce3d20$@pctechref.com> Message-ID: <003b01d21a73$7fa64510$7ef2cf30$@charter.net> > John Coleman wrote: > Another way to look at it is to imagine a XMTR whose power is varying by a > knob and some one is turning the knob back and forth. The output power is > varing along with the knob. on a slow sweep scope it would look like an AM > signal with very low freq modulation depending on the speed the knob is > turned up and down. The peak envelope power is the power (Erms * > Erms/50ohms) at the time the knob is at its max. It depends whether you are measuring in the time domain or the frequency domain. An example of time domain would be an oscilloscope or a crystal detector with no front-end selectivity between the sample and the indicator. An example of a frequency domain instrument would be a broad-band spectrum analyser or panadaptor. We all know that an AM signal does not consist of a carrier varying up and down in step with the audio, but a steady carrier and two sidebands, all existing independently of each other. This can be easily viewed on a spectrum analyser; the steady unvarying carrier is there all the time, and the sidebands vary according to the audio used to modulate the carrier. The amplitude of the carrier stands well above that of each sideband, 6 dB in the case of 100% modulation with a steady tone. This is observable with a receiver switched to narrow selectivity; we can tune USB, LSB and carrier independently. With a narrow-selectivity CW filter, we can tune in the steady carrier and hear nothing of the modulation. > "The Power of a single sine wave (360 deg) RF at the peak of the modulation envelope" > The mesurment and calculations above should satisfy this statement. That statement is dependent on the false assumption that the AM signal is indeed a single carrier frequency varying up and down in step with the modulation, a concept that was disproved back in the 1920s. Numerous articles devoted to this topic appeared in early radio magazines of that era; a debate raged for several years whether sidebands existed physically or only in the mathematics describing the modulation process. Sidebands were proved to physically exist when receiver selectivity was developed sufficiently well to actually tune through an AM signal and tune in USB, carrier and LSB as distinct signals on separate frequencies. There is no single RF sine wave that varies up and down, peaking at the crest of the modulation envelope. Instead, we see a steady carrier, and broad spectrums of frequencies to each side representing the modulation, each a mirror image of the other, and each with a peak amplitude many dB down from the steady amplitude of the carrier. Clear as mud, eh? They need to come up with a better definition of p.e.p. than that. Don k4kyv From k4kyv at charter.net Thu Sep 29 13:50:17 2016 From: k4kyv at charter.net (Donald Chester) Date: Thu, 29 Sep 2016 12:50:17 -0500 Subject: [AMRadio] The Physical Reality of Sidebands in the AM signal Message-ID: <004701d21a79$f0d19e00$d274da00$@charter.net> >From the beginnings of radiotelephony there has been a question whether sidebands exist as physical reality or only in the mathematics of modulation theory. In the early 20's this was a hotly debated topic, with a noted group of British engineers maintaining that sidebands existed only in the mathematics, while an equally well-remembered group of American engineers argued that sidebands do, in fact physically exist. Today, the issue seems settled once and for all. We can tune our modern-day highly selective receivers through double-sideband and single-sideband voice signals, and tune in upper or lower sideband, and even adjust the selectivity to the point that we can tune in the carrier minus the sidebands. Nearly everyone accepts the notion that sidebands do indeed exist physically... or do they? Maybe it's a matter of how we observe the signal, and our result is modified by our measuring techniques. Those who have studied quantum mechanics will recall the Heisenberg uncertainty Principle, which states that it is impossible to know both the position (physical location) and velocity (speed and direction) of a particle at the same time, along with the related "Observer Effect", which states that you cannot observe a system without changing something in the system. In the following thought experiment, we take this to an analogy with an amplitude modulated radio signal. Imagine a cw transmitter equipped with an electronic keyer. Also imagine that there is no shaping circuitry, so that the carrier is instantly switched between full output and zero output. Such a signal can be expected to generate extremely broad key clicks above and below the fundamental frequency because of the sharp corners of the keying waveform. Set the keying speed up to max, and send a series of dits. If the keyer is adjusted properly, the dits and spaces will be of equal length, identical to a full carrier AM signal 100 percent modulated by a perfect square wave. Suppose the keyer is adjusted to send, say, 20 dits per second when the "dit" paddle is held down. The result is a 20 Hz square-wave-modulated AM signal. Now turn the speed up. If the keyer has the capability, run it up to 100 dits per second. If you tune in the signal using a receiver with very narrow selectivity (100 Hz or less, easily achievable using today's technology), you can actually tune in the carrier, and then as you move the dial slightly you can tune in sideband components 100, 300, 500 Hz, etc. removed from the carrier frequency. A square wave consists of a fundamental frequency plus an infinite series of odd harmonics of diminishing amplitude. Theoretically you would hear carrier components spaced every 200 Hz throughout the spectrum. In a practical case, due to the finite noise floor, the diminishing amplitude of the sideband components and selectivity of the tuned circuits in the transmitter tank circuit and antenna itself, these sideband components eventually become inaudibly buried in the background noise as the receiver is tuned away from the carrier frequency. Suppose we now gradually slow down the keyer. As we change to lower keying speed, it takes more and more selectivity to discriminate between carrier and sideband components, as the modulation frequency becomes lower and the sideband components become spaced more closely together. Let's observe what happens when we slow the dit rate down to 10 dits per second. Now the fundamental modulation frequency is 10 Hz, and we can hear sideband components at 10 Hz, 30 Hz, 50 Hz, 70 Hz removed from the carrier, continuing above and below the carrier frequency at intervals of 20 Hz until we reach a point where the signals disappear into the background noise. In order to distinguish individual sideband components, we need selectivity on the order of 10 Hz, which is possible if we use resonant i.f. selectivity filters with extremely high "Q". This can be accomplished using crystal filters, regenerative amplifiers or even conventional L-C tuned circuits if we carefully design the components to have high enough Q. As we achieve extreme selectivity with these high Q resonant circuits, we observe a sometimes annoying characteristic familiarly known as "ringing." This ringing effect is due to the "flywheel effect" of a tuned circuit, the same "flywheel effect" that allows a class-C tube type final or class-E solid state final to generate a harmonic-free sinewave rf carrier waveform. The selective rf tank circuit stores energy which is re-released to fill in missing parts of the sinewave, thus filtering out the harmonics inherent to operation of these classes of amplifier. CW operators are very aware of the ringing effect of very narrow receiving filters, which can make the dits and dahs of high speed CW run together, causing the signal to be just as difficult to read with the narrow filter in line, as the same CW signal would be with a wider filter, even one that admits harmful adjacent channel interference. Kind of a damned if you do, damned if you don't scenario. Now, let's continue with our thought experiment, taking our example of code speed and selectivity to absurdity. We can slow down our keyer to a microscopic fraction of a Hertz, to the point where each dit is six months long, and the space between dits is also six months long. In effect, we are transmitting an unmodulated carrier for six months, then shutting down the transmitter for six months. But still, this is only a matter of the degree of code speed; the signal waveform is still identical to the AM transmitter tone modulated with a perfect square wave, but whose frequency is one cycle per year, or 3.17 X (10 to the -8) Hz. That means that in theory, the steady uninterrupted carrier is still being transmitted, along with a series of sideband components spaced every 6.34 X (10 to the -8) Hz. Now, carriers spaced every 6.34 X (10 to the -8) Hz apart are inarguably VERY close together, to the point that building a filter capable of separating them would likely be of complexity on the order of a successful expedition to Mars, but still theoretically possible. Let us assume we are able to build such a filter. We would undoubtedly have to resort to superconductivity in the tuned circuits, requiring components cooled to near absolute zero, and thoroughly shield every rf carrying conductor to prevent radiation loss, but here we are talking about something hypothetical, without the practical restraints of cost, construction time and availability of material. Anyway, let us just assume we were able to successfully build the required selectivity filter. The receiver would indeed be able to discriminate between sidebands and carrier of the one cycle/year or 3.17 X (10 to the -8) Hz modulated AM signal, identical to a CW transmitter with carrier on for six months and off for six months. So how can we detect a steady carrier while the transmitter is shut off for six months? The answer lies in our receiver. In order to achieve high enough selectivity to separate carrier and sideband components at such a low modulating frequency and close spacing, the Q of the tuned circuit would have to be so high that the flywheel effect, or ringing of the filter, would maintain the missing RF carrier during the six-month key-up period. This takes us back to the longstanding debate over the reality of sidebands. If we use a wideband receiver such as a crystal set with little or no front-end selectivity, we can indeed think of the AM signal precisely as a steady carrier that varies in amplitude in step with the modulating frequency. This is always the case if the total bandwidth of the signal is negligible compared to the selectivity of the receiver. Once we achieve selectivity of the same order as the bandwidth of the signal, which has been the norm for practical receivers dating from the late 1900's up to the present, reception of the signal behaves according to the principle of a steady carrier with distinctly observable upper and lower sidebands. The "holes" in the carrier at 100% negative modulation are inaudible due to the flywheel effect of the tuned circuits, even though those same "holes" may be observable on the envelope pattern of an oscilloscope. An oscilloscope set up for envelope pattern, with the deflection plates coupled directly to a sample of the transmitter's output, is a wideband device much like a crystal set. It allows us to physically observe the AM signal as a carrier of varying amplitude. A spectrum analyser on the other hand, is an instrument of high selectivity, namely a selective receiver programmed to sweep back and forth across a predetermined band of spectrum while visually displaying the amplitude of the signal falling into its passband at each instant. It clearly displays distinct upper and lower sidebands with a steady carrier in between. Furthermore, it has often been observed that the envelope pattern of a signal as displayed from a scope connected to the i.f. output of a distant receiver can be quite different from what is seen on a monitor scope at the transmitter site. This is yet another example of how the pattern is altered (distorted) by the selective components of the receiver. In conclusion, there is no correct yes or no answer to the age-old question whether or not sidebands are physical reality, or exist only in the mathematics of modulation theory. It all depends on how you physically observe the signal. Sidebands physically exist only if you use an instrument selective enough to observe them. Putting it another way, their existence depends on whether we observe the signal in the time domain or the frequency domain. Remember the Heisenberg Uncertainty Principle and the associated Observer Effect? Don k4kyv From navy.radio at gmail.com Thu Sep 29 14:13:14 2016 From: navy.radio at gmail.com (Nick England) Date: Thu, 29 Sep 2016 14:13:14 -0400 Subject: [AMRadio] FCC's AM power In-Reply-To: <003b01d21a73$7fa64510$7ef2cf30$@charter.net> References: <644138908.3346178.1474598509954.ref@mail.yahoo.com> <644138908.3346178.1474598509954@mail.yahoo.com> <007501d216c1$a7406480$f5c12d80$@charter.net> <3FC974C690EA4152AC035A91C520E75A@garyPC> <005701d217a3$3c0a6cf0$b41f46d0$@charter.net> <9c534408-c1ef-7778-c45b-6ed3c37e0aad@gmail.com> <001801d219af$229a1460$67ce3d20$@pctechref.com> <003b01d21a73$7fa64510$7ef2cf30$@charter.net> Message-ID: Don writes: "We all know that an AM signal does not consist of a carrier varying up and down in step with the audio, but a steady carrier and two sidebands, all existing independently of each other." Cool! If they are existing *independently* of each other this means I can pull the VFO tube out of my AM transmitter so the carrier disappears but the sidebands will still be there - amazing! And if I change the VFO frequency then the sidebands don't change frequency? Far out! And if the upper sideband exists independently of the lower sideband, then I can change the audio input frequency to move one sideband and the other one won't move? Equally amazing! This message is displayed on your screen as a carrier (average gray level) plus a whole bunch of 2D sidebands in the spatial frequency domain. And if those things were *independent* you wouldn't be reading this...... Nick England K4NYW www.navy-radio.com From steinerviolinist at gmail.com Thu Sep 29 14:36:42 2016 From: steinerviolinist at gmail.com (Oliver Steiner) Date: Thu, 29 Sep 2016 14:36:42 -0400 Subject: [AMRadio] The Physical Reality of Sidebands in the AM signal In-Reply-To: <004701d21a79$f0d19e00$d274da00$@charter.net> References: <004701d21a79$f0d19e00$d274da00$@charter.net> Message-ID: Don, Thank you for this very informative and beautifully written contribution. Ollie W2QXR On 9/29/16, Donald Chester wrote: > > From the beginnings of radiotelephony there has been a question whether > sidebands exist as physical reality or only in the mathematics of > modulation > theory. In the early 20's this was a hotly debated topic, with a noted > group of British engineers maintaining that sidebands existed only in the > mathematics, while an equally well-remembered group of American engineers > argued that sidebands do, in fact physically exist. > > Today, the issue seems settled once and for all. We can tune our > modern-day > highly selective receivers through double-sideband and single-sideband > voice > signals, and tune in upper or lower sideband, and even adjust the > selectivity to the point that we can tune in the carrier minus the > sidebands. Nearly everyone accepts the notion that sidebands do indeed > exist physically... or do they? > > Maybe it's a matter of how we observe the signal, and our result is > modified > by our measuring techniques. Those who have studied quantum mechanics will > recall the Heisenberg uncertainty Principle, which states that it is > impossible to know both the position (physical location) and velocity > (speed > and direction) of a particle at the same time, along with the related > "Observer Effect", which states that you cannot observe a system without > changing something in the system. In the following thought experiment, we > take this to an analogy with an amplitude modulated radio signal. > > Imagine a cw transmitter equipped with an electronic keyer. Also imagine > that there is no shaping circuitry, so that the carrier is instantly > switched between full output and zero output. Such a signal can be expected > to generate extremely broad key clicks above and below the fundamental > frequency because of the sharp corners of the keying waveform. Set the > keying speed up to max, and send a series of dits. If the keyer is > adjusted > properly, the dits and spaces will be of equal length, identical to a full > carrier AM signal 100 percent modulated by a perfect square wave. > > Suppose the keyer is adjusted to send, say, 20 dits per second when the > "dit" paddle is held down. The result is a 20 Hz square-wave-modulated AM > signal. Now turn the speed up. If the keyer has the capability, run it up > to 100 dits per second. If you tune in the signal using a receiver with > very narrow selectivity (100 Hz or less, easily achievable using today's > technology), you can actually tune in the carrier, and then as you move the > dial slightly you can tune in sideband components 100, 300, 500 Hz, etc. > removed from the carrier frequency. A square wave consists of a fundamental > frequency plus an infinite series of odd harmonics of diminishing > amplitude. > Theoretically you would hear carrier components spaced every 200 Hz > throughout the spectrum. In a practical case, due to the finite noise > floor, the diminishing amplitude of the sideband components and selectivity > of the tuned circuits in the transmitter tank circuit and antenna itself, > these sideband components eventually become inaudibly buried in the > background noise as the receiver is tuned away from the carrier frequency. > > Suppose we now gradually slow down the keyer. As we change to lower keying > speed, it takes more and more selectivity to discriminate between carrier > and sideband components, as the modulation frequency becomes lower and the > sideband components become spaced more closely together. Let's observe what > happens when we slow the dit rate down to 10 dits per second. Now the > fundamental modulation frequency is 10 Hz, and we can hear sideband > components at 10 Hz, 30 Hz, 50 Hz, 70 Hz removed from the carrier, > continuing above and below the carrier frequency at intervals of 20 Hz > until > we reach a point where the signals disappear into the background noise. > In > order to distinguish individual sideband components, we need selectivity on > the order of 10 Hz, which is possible if we use resonant i.f. selectivity > filters with extremely high "Q". This can be accomplished using crystal > filters, regenerative amplifiers or even conventional L-C tuned circuits if > we carefully design the components to have high enough Q. > > As we achieve extreme selectivity with these high Q resonant circuits, we > observe a sometimes annoying characteristic familiarly known as "ringing." > This ringing effect is due to the "flywheel effect" of a tuned circuit, the > same "flywheel effect" that allows a class-C tube type final or class-E > solid state final to generate a harmonic-free sinewave rf carrier waveform. > The selective rf tank circuit stores energy which is re-released to fill in > missing parts of the sinewave, thus filtering out the harmonics inherent to > operation of these classes of amplifier. CW operators are very aware of > the > ringing effect of very narrow receiving filters, which can make the dits > and > dahs of high speed CW run together, causing the signal to be just as > difficult to read with the narrow filter in line, as the same CW signal > would be with a wider filter, even one that admits harmful adjacent channel > interference. Kind of a damned if you do, damned if you don't scenario. > > Now, let's continue with our thought experiment, taking our example of code > speed and selectivity to absurdity. We can slow down our keyer to a > microscopic fraction of a Hertz, to the point where each dit is six months > long, and the space between dits is also six months long. In effect, we > are > transmitting an unmodulated carrier for six months, then shutting down the > transmitter for six months. But still, this is only a matter of the degree > of code speed; the signal waveform is still identical to the AM transmitter > tone modulated with a perfect square wave, but whose frequency is one cycle > per year, or 3.17 X (10 to the -8) Hz. That means that in theory, the > steady uninterrupted carrier is still being transmitted, along with a > series > of sideband components spaced every 6.34 X (10 to the -8) Hz. > > Now, carriers spaced every 6.34 X (10 to the -8) Hz apart are inarguably > VERY close together, to the point that building a filter capable of > separating them would likely be of complexity on the order of a successful > expedition to Mars, but still theoretically possible. Let us assume we are > able to build such a filter. We would undoubtedly have to resort to > superconductivity in the tuned circuits, requiring components cooled to > near > absolute zero, and thoroughly shield every rf carrying conductor to prevent > radiation loss, but here we are talking about something hypothetical, > without the practical restraints of cost, construction time and > availability > of material. Anyway, let us just assume we were able to successfully build > the required selectivity filter. > > The receiver would indeed be able to discriminate between sidebands and > carrier of the one cycle/year or 3.17 X (10 to the -8) Hz modulated AM > signal, identical to a CW transmitter with carrier on for six months and > off > for six months. So how can we detect a steady carrier while the > transmitter > is shut off for six months? The answer lies in our receiver. In order to > achieve high enough selectivity to separate carrier and sideband components > at such a low modulating frequency and close spacing, the Q of the tuned > circuit would have to be so high that the flywheel effect, or ringing of > the > filter, would maintain the missing RF carrier during the six-month key-up > period. > > This takes us back to the longstanding debate over the reality of > sidebands. > If we use a wideband receiver such as a crystal set with little or no > front-end selectivity, we can indeed think of the AM signal precisely as a > steady carrier that varies in amplitude in step with the modulating > frequency. This is always the case if the total bandwidth of the signal is > negligible compared to the selectivity of the receiver. Once we achieve > selectivity of the same order as the bandwidth of the signal, which has > been > the norm for practical receivers dating from the late 1900's up to the > present, reception of the signal behaves according to the principle of a > steady carrier with distinctly observable upper and lower sidebands. The > "holes" in the carrier at 100% negative modulation are inaudible due to the > flywheel effect of the tuned circuits, even though those same "holes" may > be > observable on the envelope pattern of an oscilloscope. > > An oscilloscope set up for envelope pattern, with the deflection plates > coupled directly to a sample of the transmitter's output, is a wideband > device much like a crystal set. It allows us to physically observe the AM > signal as a carrier of varying amplitude. A spectrum analyser on the other > hand, is an instrument of high selectivity, namely a selective receiver > programmed to sweep back and forth across a predetermined band of spectrum > while visually displaying the amplitude of the signal falling into its > passband at each instant. It clearly displays distinct upper and lower > sidebands with a steady carrier in between. > > Furthermore, it has often been observed that the envelope pattern of a > signal as displayed from a scope connected to the i.f. output of a distant > receiver can be quite different from what is seen on a monitor scope at > the > transmitter site. This is yet another example of how the pattern is > altered > (distorted) by the selective components of the receiver. > > In conclusion, there is no correct yes or no answer to the age-old question > whether or not sidebands are physical reality, or exist only in the > mathematics of modulation theory. It all depends on how you physically > observe the signal. Sidebands physically exist only if you use an > instrument selective enough to observe them. Putting it another way, their > existence depends on whether we observe the signal in the time domain or > the > frequency domain. Remember the Heisenberg Uncertainty Principle and the > associated Observer Effect? > > Don k4kyv > > ______________________________________________________________ > Our Main Website: http://www.amfone.net > AMRadio mailing list > Archives: http://mailman.qth.net/pipermail/amradio/ > List Rules (must read!): http://w5ami.net/amradiofaq.html > List Home: http://mailman.qth.net/mailman/listinfo/amradio > Post: AMRadio at mailman.qth.net > To unsubscribe, send an email to amradio-request at mailman.qth.net with > the word unsubscribe in the message body. > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to steinerviolinist at gmail.com > -- http://oliversteiner.com From ne1s at securespeed.us Thu Sep 29 15:08:07 2016 From: ne1s at securespeed.us (Larry Szendrei) Date: Thu, 29 Sep 2016 15:08:07 -0400 Subject: [AMRadio] The Physical Reality of Sidebands in the AM signal In-Reply-To: References: <004701d21a79$f0d19e00$d274da00$@charter.net> Message-ID: <742c3e32-837d-e7f3-c313-ae5a14e402fb@securespeed.us> On 9/29/16 2:36 PM, Oliver Steiner wrote: > Don, > > Thank you for this very informative and beautifully written contribution. > > Ollie > W2QXR > My sentiments exactly. A very interesting analysis, and one in which I can find no technical error. Don certainly has given this subject a lot of critical thought. That one's a keeper and is getting filed away for future reference. 73, -Larry/NE1S From tvictor at attglobal.net Thu Sep 29 23:02:22 2016 From: tvictor at attglobal.net (Vic Mukal) Date: Thu, 29 Sep 2016 23:02:22 -0400 Subject: [AMRadio] AMRadio Digest, Vol 152, Issue 10 In-Reply-To: References: Message-ID: Don, I would also like to thank you for submitting such an interesting technical article. Tom WB2STR On Thu, Sep 29, 2016 at 2:37 PM, wrote: > Send AMRadio mailing list submissions to > amradio at mailman.qth.net > > To subscribe or unsubscribe via the World Wide Web, visit > http://mailman.qth.net/mailman/listinfo/amradio > or, via email, send a message with subject or body 'help' to > amradio-request at mailman.qth.net > > You can reach the person managing the list at > amradio-owner at mailman.qth.net > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of AMRadio digest..." > > > Today's Topics: > > 1. The Physical Reality of Sidebands in the AM signal > (Donald Chester) > 2. Re: FCC's AM power (Nick England) > 3. Re: The Physical Reality of Sidebands in the AM signal > (Oliver Steiner) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Thu, 29 Sep 2016 12:50:17 -0500 > From: "Donald Chester" > To: > Subject: [AMRadio] The Physical Reality of Sidebands in the AM signal > Message-ID: <004701d21a79$f0d19e00$d274da00$@charter.net> > Content-Type: text/plain; charset="us-ascii" > > > >From the beginnings of radiotelephony there has been a question whether > sidebands exist as physical reality or only in the mathematics of > modulation > theory. In the early 20's this was a hotly debated topic, with a noted > group of British engineers maintaining that sidebands existed only in the > mathematics, while an equally well-remembered group of American engineers > argued that sidebands do, in fact physically exist. > > Today, the issue seems settled once and for all. We can tune our > modern-day > highly selective receivers through double-sideband and single-sideband > voice > signals, and tune in upper or lower sideband, and even adjust the > selectivity to the point that we can tune in the carrier minus the > sidebands. Nearly everyone accepts the notion that sidebands do indeed > exist physically... or do they? > > Maybe it's a matter of how we observe the signal, and our result is > modified > by our measuring techniques. Those who have studied quantum mechanics will > recall the Heisenberg uncertainty Principle, which states that it is > impossible to know both the position (physical location) and velocity > (speed > and direction) of a particle at the same time, along with the related > "Observer Effect", which states that you cannot observe a system without > changing something in the system. In the following thought experiment, we > take this to an analogy with an amplitude modulated radio signal. > > Imagine a cw transmitter equipped with an electronic keyer. Also imagine > that there is no shaping circuitry, so that the carrier is instantly > switched between full output and zero output. Such a signal can be expected > to generate extremely broad key clicks above and below the fundamental > frequency because of the sharp corners of the keying waveform. Set the > keying speed up to max, and send a series of dits. If the keyer is > adjusted > properly, the dits and spaces will be of equal length, identical to a full > carrier AM signal 100 percent modulated by a perfect square wave. > > Suppose the keyer is adjusted to send, say, 20 dits per second when the > "dit" paddle is held down. The result is a 20 Hz square-wave-modulated AM > signal. Now turn the speed up. If the keyer has the capability, run it up > to 100 dits per second. If you tune in the signal using a receiver with > very narrow selectivity (100 Hz or less, easily achievable using today's > technology), you can actually tune in the carrier, and then as you move the > dial slightly you can tune in sideband components 100, 300, 500 Hz, etc. > removed from the carrier frequency. A square wave consists of a fundamental > frequency plus an infinite series of odd harmonics of diminishing > amplitude. > Theoretically you would hear carrier components spaced every 200 Hz > throughout the spectrum. In a practical case, due to the finite noise > floor, the diminishing amplitude of the sideband components and selectivity > of the tuned circuits in the transmitter tank circuit and antenna itself, > these sideband components eventually become inaudibly buried in the > background noise as the receiver is tuned away from the carrier frequency. > > Suppose we now gradually slow down the keyer. As we change to lower keying > speed, it takes more and more selectivity to discriminate between carrier > and sideband components, as the modulation frequency becomes lower and the > sideband components become spaced more closely together. Let's observe what > happens when we slow the dit rate down to 10 dits per second. Now the > fundamental modulation frequency is 10 Hz, and we can hear sideband > components at 10 Hz, 30 Hz, 50 Hz, 70 Hz removed from the carrier, > continuing above and below the carrier frequency at intervals of 20 Hz > until > we reach a point where the signals disappear into the background noise. > In > order to distinguish individual sideband components, we need selectivity on > the order of 10 Hz, which is possible if we use resonant i.f. selectivity > filters with extremely high "Q". This can be accomplished using crystal > filters, regenerative amplifiers or even conventional L-C tuned circuits if > we carefully design the components to have high enough Q. > > As we achieve extreme selectivity with these high Q resonant circuits, we > observe a sometimes annoying characteristic familiarly known as "ringing." > This ringing effect is due to the "flywheel effect" of a tuned circuit, the > same "flywheel effect" that allows a class-C tube type final or class-E > solid state final to generate a harmonic-free sinewave rf carrier waveform. > The selective rf tank circuit stores energy which is re-released to fill in > missing parts of the sinewave, thus filtering out the harmonics inherent to > operation of these classes of amplifier. CW operators are very aware of > the > ringing effect of very narrow receiving filters, which can make the dits > and > dahs of high speed CW run together, causing the signal to be just as > difficult to read with the narrow filter in line, as the same CW signal > would be with a wider filter, even one that admits harmful adjacent channel > interference. Kind of a damned if you do, damned if you don't scenario. > > Now, let's continue with our thought experiment, taking our example of code > speed and selectivity to absurdity. We can slow down our keyer to a > microscopic fraction of a Hertz, to the point where each dit is six months > long, and the space between dits is also six months long. In effect, we > are > transmitting an unmodulated carrier for six months, then shutting down the > transmitter for six months. But still, this is only a matter of the degree > of code speed; the signal waveform is still identical to the AM transmitter > tone modulated with a perfect square wave, but whose frequency is one cycle > per year, or 3.17 X (10 to the -8) Hz. That means that in theory, the > steady uninterrupted carrier is still being transmitted, along with a > series > of sideband components spaced every 6.34 X (10 to the -8) Hz. > > Now, carriers spaced every 6.34 X (10 to the -8) Hz apart are inarguably > VERY close together, to the point that building a filter capable of > separating them would likely be of complexity on the order of a successful > expedition to Mars, but still theoretically possible. Let us assume we are > able to build such a filter. We would undoubtedly have to resort to > superconductivity in the tuned circuits, requiring components cooled to > near > absolute zero, and thoroughly shield every rf carrying conductor to prevent > radiation loss, but here we are talking about something hypothetical, > without the practical restraints of cost, construction time and > availability > of material. Anyway, let us just assume we were able to successfully build > the required selectivity filter. > > The receiver would indeed be able to discriminate between sidebands and > carrier of the one cycle/year or 3.17 X (10 to the -8) Hz modulated AM > signal, identical to a CW transmitter with carrier on for six months and > off > for six months. So how can we detect a steady carrier while the > transmitter > is shut off for six months? The answer lies in our receiver. In order to > achieve high enough selectivity to separate carrier and sideband components > at such a low modulating frequency and close spacing, the Q of the tuned > circuit would have to be so high that the flywheel effect, or ringing of > the > filter, would maintain the missing RF carrier during the six-month key-up > period. > > This takes us back to the longstanding debate over the reality of > sidebands. > If we use a wideband receiver such as a crystal set with little or no > front-end selectivity, we can indeed think of the AM signal precisely as a > steady carrier that varies in amplitude in step with the modulating > frequency. This is always the case if the total bandwidth of the signal is > negligible compared to the selectivity of the receiver. Once we achieve > selectivity of the same order as the bandwidth of the signal, which has > been > the norm for practical receivers dating from the late 1900's up to the > present, reception of the signal behaves according to the principle of a > steady carrier with distinctly observable upper and lower sidebands. The > "holes" in the carrier at 100% negative modulation are inaudible due to the > flywheel effect of the tuned circuits, even though those same "holes" may > be > observable on the envelope pattern of an oscilloscope. > > An oscilloscope set up for envelope pattern, with the deflection plates > coupled directly to a sample of the transmitter's output, is a wideband > device much like a crystal set. It allows us to physically observe the AM > signal as a carrier of varying amplitude. A spectrum analyser on the other > hand, is an instrument of high selectivity, namely a selective receiver > programmed to sweep back and forth across a predetermined band of spectrum > while visually displaying the amplitude of the signal falling into its > passband at each instant. It clearly displays distinct upper and lower > sidebands with a steady carrier in between. > > Furthermore, it has often been observed that the envelope pattern of a > signal as displayed from a scope connected to the i.f. output of a distant > receiver can be quite different from what is seen on a monitor scope at > the > transmitter site. This is yet another example of how the pattern is > altered > (distorted) by the selective components of the receiver. > > In conclusion, there is no correct yes or no answer to the age-old question > whether or not sidebands are physical reality, or exist only in the > mathematics of modulation theory. It all depends on how you physically > observe the signal. Sidebands physically exist only if you use an > instrument selective enough to observe them. Putting it another way, their > existence depends on whether we observe the signal in the time domain or > the > frequency domain. Remember the Heisenberg Uncertainty Principle and the > associated Observer Effect? > > Don k4kyv > > > > ------------------------------ > > Message: 2 > Date: Thu, 29 Sep 2016 14:13:14 -0400 > From: Nick England > To: Donald Chester > Cc: Discussion of AM Radio in the Amateur Service > > Subject: Re: [AMRadio] FCC's AM power > Message-ID: > iJtz2OGTUw at mail.gmail.com> > Content-Type: text/plain; charset=UTF-8 > > Don writes: > "We all know that an AM signal does not consist of a carrier varying up and > down in step with the audio, but a steady carrier and two sidebands, all > existing independently of each other." > > Cool! If they are existing *independently* of each other this means I can > pull the VFO tube out of my AM transmitter so the carrier disappears but > the sidebands will still be there - amazing! And if I change the VFO > frequency then the sidebands don't change frequency? Far out! And if the > upper sideband exists independently of the lower sideband, then I can > change the audio input frequency to move one sideband and the other one > won't move? Equally amazing! > > This message is displayed on your screen as a carrier (average gray level) > plus a whole bunch of 2D sidebands in the spatial frequency domain. And if > those things were *independent* you wouldn't be reading this...... > > Nick England K4NYW > www.navy-radio.com > > > ------------------------------ > > Message: 3 > Date: Thu, 29 Sep 2016 14:36:42 -0400 > From: Oliver Steiner > To: Donald Chester > Cc: amradio at mailman.qth.net > Subject: Re: [AMRadio] The Physical Reality of Sidebands in the AM > signal > Message-ID: > gmail.com> > Content-Type: text/plain; charset=UTF-8 > > Don, > > Thank you for this very informative and beautifully written contribution. > > Ollie > W2QXR > > On 9/29/16, Donald Chester wrote: > > > > From the beginnings of radiotelephony there has been a question whether > > sidebands exist as physical reality or only in the mathematics of > > modulation > > theory. In the early 20's this was a hotly debated topic, with a noted > > group of British engineers maintaining that sidebands existed only in the > > mathematics, while an equally well-remembered group of American engineers > > argued that sidebands do, in fact physically exist. > > > > Today, the issue seems settled once and for all. We can tune our > > modern-day > > highly selective receivers through double-sideband and single-sideband > > voice > > signals, and tune in upper or lower sideband, and even adjust the > > selectivity to the point that we can tune in the carrier minus the > > sidebands. Nearly everyone accepts the notion that sidebands do indeed > > exist physically... or do they? > > > > Maybe it's a matter of how we observe the signal, and our result is > > modified > > by our measuring techniques. Those who have studied quantum mechanics > will > > recall the Heisenberg uncertainty Principle, which states that it is > > impossible to know both the position (physical location) and velocity > > (speed > > and direction) of a particle at the same time, along with the related > > "Observer Effect", which states that you cannot observe a system without > > changing something in the system. In the following thought experiment, we > > take this to an analogy with an amplitude modulated radio signal. > > > > Imagine a cw transmitter equipped with an electronic keyer. Also imagine > > that there is no shaping circuitry, so that the carrier is instantly > > switched between full output and zero output. Such a signal can be > expected > > to generate extremely broad key clicks above and below the fundamental > > frequency because of the sharp corners of the keying waveform. Set the > > keying speed up to max, and send a series of dits. If the keyer is > > adjusted > > properly, the dits and spaces will be of equal length, identical to a > full > > carrier AM signal 100 percent modulated by a perfect square wave. > > > > Suppose the keyer is adjusted to send, say, 20 dits per second when the > > "dit" paddle is held down. The result is a 20 Hz square-wave-modulated AM > > signal. Now turn the speed up. If the keyer has the capability, run it > up > > to 100 dits per second. If you tune in the signal using a receiver with > > very narrow selectivity (100 Hz or less, easily achievable using today's > > technology), you can actually tune in the carrier, and then as you move > the > > dial slightly you can tune in sideband components 100, 300, 500 Hz, etc. > > removed from the carrier frequency. A square wave consists of a > fundamental > > frequency plus an infinite series of odd harmonics of diminishing > > amplitude. > > Theoretically you would hear carrier components spaced every 200 Hz > > throughout the spectrum. In a practical case, due to the finite noise > > floor, the diminishing amplitude of the sideband components and > selectivity > > of the tuned circuits in the transmitter tank circuit and antenna itself, > > these sideband components eventually become inaudibly buried in the > > background noise as the receiver is tuned away from the carrier > frequency. > > > > Suppose we now gradually slow down the keyer. As we change to lower > keying > > speed, it takes more and more selectivity to discriminate between carrier > > and sideband components, as the modulation frequency becomes lower and > the > > sideband components become spaced more closely together. Let's observe > what > > happens when we slow the dit rate down to 10 dits per second. Now the > > fundamental modulation frequency is 10 Hz, and we can hear sideband > > components at 10 Hz, 30 Hz, 50 Hz, 70 Hz removed from the carrier, > > continuing above and below the carrier frequency at intervals of 20 Hz > > until > > we reach a point where the signals disappear into the background noise. > > In > > order to distinguish individual sideband components, we need selectivity > on > > the order of 10 Hz, which is possible if we use resonant i.f. selectivity > > filters with extremely high "Q". This can be accomplished using crystal > > filters, regenerative amplifiers or even conventional L-C tuned circuits > if > > we carefully design the components to have high enough Q. > > > > As we achieve extreme selectivity with these high Q resonant circuits, we > > observe a sometimes annoying characteristic familiarly known as > "ringing." > > This ringing effect is due to the "flywheel effect" of a tuned circuit, > the > > same "flywheel effect" that allows a class-C tube type final or class-E > > solid state final to generate a harmonic-free sinewave rf carrier > waveform. > > The selective rf tank circuit stores energy which is re-released to fill > in > > missing parts of the sinewave, thus filtering out the harmonics inherent > to > > operation of these classes of amplifier. CW operators are very aware of > > the > > ringing effect of very narrow receiving filters, which can make the dits > > and > > dahs of high speed CW run together, causing the signal to be just as > > difficult to read with the narrow filter in line, as the same CW signal > > would be with a wider filter, even one that admits harmful adjacent > channel > > interference. Kind of a damned if you do, damned if you don't scenario. > > > > Now, let's continue with our thought experiment, taking our example of > code > > speed and selectivity to absurdity. We can slow down our keyer to a > > microscopic fraction of a Hertz, to the point where each dit is six > months > > long, and the space between dits is also six months long. In effect, we > > are > > transmitting an unmodulated carrier for six months, then shutting down > the > > transmitter for six months. But still, this is only a matter of the > degree > > of code speed; the signal waveform is still identical to the AM > transmitter > > tone modulated with a perfect square wave, but whose frequency is one > cycle > > per year, or 3.17 X (10 to the -8) Hz. That means that in theory, the > > steady uninterrupted carrier is still being transmitted, along with a > > series > > of sideband components spaced every 6.34 X (10 to the -8) Hz. > > > > Now, carriers spaced every 6.34 X (10 to the -8) Hz apart are inarguably > > VERY close together, to the point that building a filter capable of > > separating them would likely be of complexity on the order of a > successful > > expedition to Mars, but still theoretically possible. Let us assume we > are > > able to build such a filter. We would undoubtedly have to resort to > > superconductivity in the tuned circuits, requiring components cooled to > > near > > absolute zero, and thoroughly shield every rf carrying conductor to > prevent > > radiation loss, but here we are talking about something hypothetical, > > without the practical restraints of cost, construction time and > > availability > > of material. Anyway, let us just assume we were able to successfully > build > > the required selectivity filter. > > > > The receiver would indeed be able to discriminate between sidebands and > > carrier of the one cycle/year or 3.17 X (10 to the -8) Hz modulated AM > > signal, identical to a CW transmitter with carrier on for six months and > > off > > for six months. So how can we detect a steady carrier while the > > transmitter > > is shut off for six months? The answer lies in our receiver. In order > to > > achieve high enough selectivity to separate carrier and sideband > components > > at such a low modulating frequency and close spacing, the Q of the tuned > > circuit would have to be so high that the flywheel effect, or ringing of > > the > > filter, would maintain the missing RF carrier during the six-month key-up > > period. > > > > This takes us back to the longstanding debate over the reality of > > sidebands. > > If we use a wideband receiver such as a crystal set with little or no > > front-end selectivity, we can indeed think of the AM signal precisely as > a > > steady carrier that varies in amplitude in step with the modulating > > frequency. This is always the case if the total bandwidth of the signal > is > > negligible compared to the selectivity of the receiver. Once we achieve > > selectivity of the same order as the bandwidth of the signal, which has > > been > > the norm for practical receivers dating from the late 1900's up to the > > present, reception of the signal behaves according to the principle of a > > steady carrier with distinctly observable upper and lower sidebands. The > > "holes" in the carrier at 100% negative modulation are inaudible due to > the > > flywheel effect of the tuned circuits, even though those same "holes" may > > be > > observable on the envelope pattern of an oscilloscope. > > > > An oscilloscope set up for envelope pattern, with the deflection plates > > coupled directly to a sample of the transmitter's output, is a wideband > > device much like a crystal set. It allows us to physically observe the AM > > signal as a carrier of varying amplitude. A spectrum analyser on the > other > > hand, is an instrument of high selectivity, namely a selective receiver > > programmed to sweep back and forth across a predetermined band of > spectrum > > while visually displaying the amplitude of the signal falling into its > > passband at each instant. It clearly displays distinct upper and lower > > sidebands with a steady carrier in between. > > > > Furthermore, it has often been observed that the envelope pattern of a > > signal as displayed from a scope connected to the i.f. output of a > distant > > receiver can be quite different from what is seen on a monitor scope at > > the > > transmitter site. This is yet another example of how the pattern is > > altered > > (distorted) by the selective components of the receiver. > > > > In conclusion, there is no correct yes or no answer to the age-old > question > > whether or not sidebands are physical reality, or exist only in the > > mathematics of modulation theory. It all depends on how you physically > > observe the signal. Sidebands physically exist only if you use an > > instrument selective enough to observe them. Putting it another way, > their > > existence depends on whether we observe the signal in the time domain or > > the > > frequency domain. Remember the Heisenberg Uncertainty Principle and the > > associated Observer Effect? > > > > Don k4kyv > > > > ______________________________________________________________ > > Our Main Website: http://www.amfone.net > > AMRadio mailing list > > Archives: http://mailman.qth.net/pipermail/amradio/ > > List Rules (must read!): http://w5ami.net/amradiofaq.html > > List Home: http://mailman.qth.net/mailman/listinfo/amradio > > Post: AMRadio at mailman.qth.net > > To unsubscribe, send an email to amradio-request at mailman.qth.net with > > the word unsubscribe in the message body. > > > > This list hosted by: http://www.qsl.net > > Please help support this email list: http://www.qsl.net/donate.html > > Message delivered to steinerviolinist at gmail.com > > > > > -- > http://oliversteiner.com > > > ------------------------------ > > Subject: Digest Footer > > ______________________________________________________________ > AMRadio mailing list > Home: http://mailman.qth.net/mailman/listinfo/amradio > Help: http://mailman.qth.net/mmfaq.html > Post: mailto:AMRadio at mailman.qth.net > > > ------------------------------ > > End of AMRadio Digest, Vol 152, Issue 10 > **************************************** > From ka1kaq at gmail.com Fri Sep 30 12:14:54 2016 From: ka1kaq at gmail.com (Todd, KA1KAQ) Date: Fri, 30 Sep 2016 12:14:54 -0400 Subject: [AMRadio] The Physical Reality of Sidebands in the AM signal In-Reply-To: <742c3e32-837d-e7f3-c313-ae5a14e402fb@securespeed.us> References: <004701d21a79$f0d19e00$d274da00$@charter.net> <742c3e32-837d-e7f3-c313-ae5a14e402fb@securespeed.us> Message-ID: On Thu, Sep 29, 2016 at 3:08 PM, Larry Szendrei wrote: > On 9/29/16 2:36 PM, Oliver Steiner wrote: > >> Don, >> >> Thank you for this very informative and beautifully written contribution. >> >> Ollie >> W2QXR >> >> My sentiments exactly. A very interesting analysis, and one in which I > can find no technical error. Don certainly has given this subject a lot of > critical thought. That one's a keeper and is getting filed away for future > reference. > That and a lot of other great information is available on AMfone.net thanks to Steve/K4HX. He set up a sub forum called Don's Tech Talks back in 2011 specifically for isolating and preserving as much of this great info as possible, for the benefit of all. http://amfone.net/Amforum/index.php?board=67.0 Though there are a multitude of excellent posts and topics in the Tech section, over time they get pushed further and further back through the 'pages' and become more difficult to find. Getting some of them into a more centralized location where they wouldn't scroll off the page was the answer. There is also a forum set up for Walt Maxwell/W2DU (SK) where he related a lot of his early satellite and other history. Walt is probably best known in the amateur community for his Reflections Vols I-III books on aerials and transmission lines. He published numerous other articles as well. http://amfone.net/Amforum/index.php?board=66.0 Definitely a lot of good material available for the technically-inclined or just plain curious. Print it, save it, share it with others. ~ Todd, KA1KAQ/4 From jcandela at prodigy.net Fri Sep 30 14:36:00 2016 From: jcandela at prodigy.net (Jim Candela) Date: Fri, 30 Sep 2016 18:36:00 +0000 (UTC) Subject: [AMRadio] The Physical Reality of Sidebands in the AM signal In-Reply-To: References: <004701d21a79$f0d19e00$d274da00$@charter.net> <742c3e32-837d-e7f3-c313-ae5a14e402fb@securespeed.us> Message-ID: <112572455.423911.1475260560248@mail.yahoo.com> On Friday, September 30, 2016 11:15 AM, "Todd, KA1KAQ" wrote: snip That and a lot of other great information is available on AMfone.net thanks to Steve/K4HX. He set up a sub forum called Don's Tech Talks back in 2011 specifically for isolating and preserving as much of this great info as possible, for the benefit of all. http://amfone.net/Amforum/index.php?board=67.0 snip ~ Todd,? KA1KAQ/4 Those posts were all before Don was publicly censured on that forum. That's too bad and Don has moved on. JimWd5JKO ______________________________________________________________ Our Main Website: http://www.amfone.net AMRadio mailing list Archives: http://mailman.qth.net/pipermail/amradio/ List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Post: AMRadio at mailman.qth.net To unsubscribe, send an email to amradio-request at mailman.qth.net with the word unsubscribe in the message body. This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to jcandela at prodigy.net From wz5q at wz5q.net Fri Sep 30 18:11:14 2016 From: wz5q at wz5q.net (Mike - WZ5Q) Date: Fri, 30 Sep 2016 17:11:14 -0500 Subject: [AMRadio] The Physical Reality of Sidebands in the AM signal In-Reply-To: <112572455.423911.1475260560248@mail.yahoo.com> References: <004701d21a79$f0d19e00$d274da00$@charter.net> <742c3e32-837d-e7f3-c313-ae5a14e402fb@securespeed.us> <112572455.423911.1475260560248@mail.yahoo.com> Message-ID: <57EEE302.1050202@wz5q.net> Yea, that was an unbelievable travesty. There have been many other good people that have left for the same reason. I no longer post there. Mike WZ5Q On 9/30/2016 1:36 PM, Jim Candela wrote: > On Friday, September 30, 2016 11:15 AM, "Todd, KA1KAQ" wrote: > > snip > > That and a lot of other great information is available on AMfone.net thanks > to Steve/K4HX. He set up a sub forum called Don's Tech Talks back in 2011 > specifically for isolating and preserving as much of this great info as > possible, for the benefit of all. > > http://amfone.net/Amforum/index.php?board=67.0 > > snip > > ~ Todd, KA1KAQ/4 > > Those posts were all before Don was publicly censured on that forum. That's too bad and Don has moved on. > JimWd5JKO

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