[AMRadio] WTB SB-220


Edward B Richards zuu6k at juno.com
Tue Sep 28 13:08:03 EDT 2004


Hi Bret;

That could be because the ratio of 25 watts to 100 watts is 4, an
increase of 6 dB, while the ratio of 300 to 500 is 1.7, an increase of
2.2 dB and 300 to 600 is a ratio of 2 or 3 dB.

73, Ed Richards K6UUZ


On Tue, 28 Sep 2004 08:14:24 -0400 Brett gazdzinski
<Brett.gazdzinski at mci.com> writes:
> I know about the DB thing, but people running a bit of power always
> seem much stronger than the guys running 25 or 50 watts.
> 
> I cant say why, but in a qso with a bunch of people, the guys
> running 200 to 300 watts are always much stronger on the meter, and
> sounding,
> than the 50 watt guys.
> 
> For some reason, the biggest jump seems to be between about 25 watts
> and 100 watts.
> I don't think you HEAR as much change between say 300 and 500 watts,
> or even 300 and 600 watts, but go between 25 and 100 watts and it 
> seems very
> noticeable at the other end.
> 
> Maybe the losses in the antenna circuit are a much bigger percentage
> of the power out when running 25 or 50 watts?
>  
> You can see the difference in signal strength when someone turns up 
> the
> power,
> and it seems to track with the DB rule, but there still seems to be
> some threshold effect in most cases.
> With 25 watts, its hard to get clearly above the noise floor in many
> cases, while 100 watts and up does it easy in clear band conditions.
> 
> Most times, on clear conditions on 40 meters, the guy running the
> rice box at 25 watts is just above the noise floor at about 1 s 
> unit.
> He may run between s1 and s3.
> The guy running 100 watts will run s6 to s9 or higher, and be
> arm chair copy. That FIRST 3 to 6 db boost seems to be the most 
> critical. 
> 
> And I have NEVER heard someone running 25 watts and a REALLY good 
> antenna
> out strapping a 500 watt rig into a regular antenna.
> 
> 
> And, although its easy to run an amp and boost power a little, it
> seems crazy to run a pair of heavy tubes and get 300 watts out,
> when a pair of 813 tubes plate modulated will do 700 watts
> of carrier easy, and well over 2000 watts pep!
> 
> A pair of 812a's will give 300 watts carrier without trouble!
> 
> 
> Brett
> N2DTS
>   
> 
> 
> 
> -----Original Message-----
> From: amradio-bounces at mailman.qth.net
> [mailto:amradio-bounces at mailman.qth.net] On Behalf Of RJ Mattson
> Sent: Monday, September 27, 2004 7:07 PM
> To: Discussion of AM Radio
> Subject: Re: [AMRadio] WTB SB-220
> 
> 
> Again, It would be an S1 signal above a s9/30db level noise -  a 
> barely
> perceivable difference. You would have to go from 100 to ~ 6,400 
> watts to
> get an S3 signal above that noise level.  bob...w2ami
> www.qrz.com/callsign/w2ami
> 
> 
> ----- Original Message ----- 
> From: "George Pritchard" <gpritchard at comtechpst.com>
> To: "'Discussion of AM Radio'" <amradio at mailman.qth.net>
> Sent: Monday, September 27, 2004 9:38 AM
> Subject: RE: [AMRadio] WTB SB-220
> 
> 
> > When the interference is also at 30 over S9(even if it's static 
> > crashes) a 36 dB over signal using the 400 watts helps. First put 
> up 
> > the best ant... Then crank-it with juice!!! George AB2KC
> > 1KW 4X1 lives
> >
> > -----Original Message-----
> > From: amradio-bounces at mailman.qth.net 
> > [mailto:amradio-bounces at mailman.qth.net] On Behalf Of RJ Mattson
> > Sent: Monday, September 27, 2004 9:27 AM
> > To: Discussion of AM Radio
> > Subject: Re: [AMRadio] WTB SB-220
> >
> >
> > No matter what the spin, 100 to 400 watts is only 1 s-unit and 
> barely 
> > perceptible at the receiver. A 30db/s9 signal is from a good 
> antenna 
> > not from 100 or 400 watts.
> > bob...w2ami
> > www.qrz.com/callsign/w2ami
> >
> >
> > ----- Original Message -----
> > From: "Jim Candela" <jcandela at prodigy.net>
> > To: <amradio at mailman.qth.net>
> > Sent: Sunday, September 26, 2004 10:47 PM
> > Subject: Re: [AMRadio] WTB SB-220
> > >
> > > Hmmm, the boys on 3878 are running 1500 watts pep plus
> > > on USB, and there is a 100 watt AM'er calling CQ on
> > > 3880. How much of an antenna would the AM'er need to overcome 
> the 
> > > S/N ratio? I think Astabula Bill, W8VYZ says it all:
> > >
> > > http://www.amwindow.org/audio/mov/w8vyz.mov
> > >
> > > Ever hear Bill running 100 watts? When Bill and Less
> > > K6HQI (sk) were regulars on 14286 they had to run
> > > heavy iron to hold the frequency. A 100 watt rig was
> > > seldom heard whereas a 500 watt rig (that 6db again)
> > > was often armchair copy, and sometimes often drive the
> > > QRM away.
> > >
> > > Regards,
> > > Jim
> > >
> > > RJ Mattson <rjmattson at hvi.net> wrote:
> > > If you can't get out consistantly with a Viking II,
> > > you need an antenna -
> > > not an amp.
> > > bob...w2ami
> > > www.qrz.com/callsign/w2ami
> >
> >
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