[AMRadio] Re:Balanced Line Antenna Tuner


Donald R. R Moore wa5ffk at juno.com
Thu Sep 22 11:18:37 EDT 2005


I want to construct a balanced line antenna tuner to cover 160-10 meters,
does any one have any good ideas on one, and where a diagram can be
obtained.

Thanks,
Don W5FFK
On Thu, 22 Sep 2005 10:12:24 -0400 (EDT) amradio-request at mailman.qth.net
writes:
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> Today's Topics:
> 
>    1. Collins  filter (Rivpapa1 at aol.com)
>    2. Re: Pi-Net vs Link Couple (bcarling at cfl.rr.com)
>    3. Re: Pi-Net vs Link Couple (ronnie.hull)
>    4. RE: Pi-Net vs Link Couple (Brett gazdzinski)
>    5. Re: Pi-Net vs Link Couple (Geoff)
>    6. Re: Pi-Net vs Link Couple (bcarling at cfl.rr.com)
>    7. Re: Pi-Net vs Link Couple (ronnie.hull)
>    8. Re: Pi-Net vs Link Couple (ronnie.hull)
>    9. Re: Pi-Net vs Link Couple (Geoff)
>   10. Re: Pi-Net vs Link Couple (Geoff)
> 
> 
> ----------------------------------------------------------------------
> 
> Message: 1
> Date: Thu, 22 Sep 2005 04:19:26 EDT
> From: Rivpapa1 at aol.com
> Subject: [AMRadio] Collins  filter
> To: amradio at mailman.qth.net
> Message-ID: <bd.60841fd0.3063c30e at aol.com>
> Content-Type: text/plain; charset="US-ASCII"
> 
> I am looking for the 6.0khz  filter..Pt #  F-455-J60.. for the 
> Collins 75A4 
> Reciever...Tnx Ron W6MAU
> 
> 
> ------------------------------
> 
> Message: 2
> Date: Thu, 22 Sep 2005 07:37:13 -0400
> From: bcarling at cfl.rr.com
> Subject: Re: [AMRadio] Pi-Net vs Link Couple
> To: Discussion of AM Radio <amradio at mailman.qth.net>
> Message-ID: <43325F29.9989.91003D at localhost>
> Content-Type: text/plain; charset=US-ASCII
> 
> On 21 Sep 2005 at 21:45, Geoff wrote:
> 
> > I've heard recently that matching the output of the Class C 
> > pate-modulated final to the antenna is better, and more efficiently 
> 
> > achieved by link coupling, vs Pi-Net.  
> 
> Where did you hear that?
> 
> > On the other hand, it's argued 
> > that Pi-Net coupling produces less RFI than link coupling does.
> > 
> > So, which is better?
> 
> Pi Network.
> 
> > Why?
> 
> I can only tell you from my own experiences, that a) You already 
> answered the foirst part - less harmonics, and
> B) you get more power out.
> 
> That is enough to persuade me.
> 
> I know some folks swear by link coupling.
> I swear at it!
> 
> I had an Eldico rig once with an 807 final.
> I could only get about 15 watts out with the link coupling.
> I re-confiugred it to be a pi network and immediately had 
> no diifficulty getting about 35 watts out.
> 
> Now some may argue that the link coupling circuit wasn't 
> made right, wasn't adjust right etc. etc. I don't care about 
> that.  I just like pi networks.  If  it was good enough for 
> Art Collins...
> 
> 
> 
> 
> ------------------------------
> 
> Message: 3
> Date: Thu, 22 Sep 2005 07:53:13 -0400
> From: "ronnie.hull" <ronnie.hull at glowbugs.com>
> Subject: Re: [AMRadio] Pi-Net vs Link Couple
> To: "Mike Dorworth, K4XM" <k4xm at arczip.com>,        Discussion of AM 
> Radio
>         <amradio at mailman.qth.net>
> Message-ID: <20050922115313.M14136 at glowbugs.com>
> Content-Type: text/plain; charset=iso-8859-1
> 
> 
> Mike I'm the fellow that is going to build up a Class C final using 
> a 450TL. 
> I would love to get a copy of that schematic for the 450TH rig in 
> the Editors 
> and Engineers handbook. I have a few of those, but apparently, not 
> that one.
> 
> I have a very nice B&W 850A or 852 that I can use in this rig. 
> Either should 
> handle that tube fine, considering I'm not going to run much more 
> than 2500 
> volts on it anyway. Maybe 3000.
> 
> I just got the worled biggest honker daddy plate transformer from 
> W5OMR. 
> 8200V center tapped ( 4100 - 0 - 4100 ) at 4.5KVA !!!  Yeah suh, 
> takes 3 men 
> and a dolly to move it!!
> 
> This will be a fun project.
> 
> 73's & batten down the hatches, here comes Rita..
> 
> W5SUM
> 
> 
> ---------- Original Message -----------
> From: "Mike Dorworth,K4XM" <k4xm at arczip.com>
> To: "Discussion of AM Radio" <amradio at mailman.qth.net>
> Sent: Wed, 21 Sep 2005 23:10:59 -0400
> Subject: Re: [AMRadio] Pi-Net vs Link Couple
> 
> > The Pi-Net will give a total of 50 db suppresion of harmonics. 
> about 
> > 20 in one spot and 30 in the other. Link couple can pass harmonics 
> 
> > to VHF by capacity coupling, hence the Faraday Shield Links used 
> for 
> > same later on. There is a nice single 450th Pi-Net rig shown in 
> the 
> > Editor and Engineers handbook. Also a couple of single ended ones 
> in 
> > the 1950 ARRL Handbook (for triodes).  Some triodes that require 
> > lots and lots or drive can unbalance the grid tank, which is 
> > required for triodes using Pi-Net. Lo capacity tubes like the 
> 450th 
> > is OK. The old timers mostly used tuners (antenna) and open wire 
> > feeders to keep the harmonics down. Hazletine link neutralization 
> 
> > can also be used and no split tanks are needed in or out. Remember 
> 
> > Class C , which is required for Hi level AM, is a extreme 
> distortion 
> >  and harmonic generator so that some plan need to be in place to 
> > handle the soup. Also a single band dipole is very frequency 
> > selective and cuts way down on harmonics by itself. Multiband 
> > dipoles, beams and multi dipole on one feeder and traps etc (G5RV) 
> 
> > are an open invitation to spread gook with only link output. Also 
> 
> > the guys that use CB lin years with no half wave filters get away 
> in 
> > mobile service without too many problems  due to the narrow 
> > frequency discrimination of mobile antennas. Hope this helps, 73 
> Mike
> > 
> > ----- Original Message ----- 
> > From: "Geoff" <w5omr at satx.rr.com>
> > To: "Discussion of AM Radio" <amradio at mailman.qth.net>
> > Sent: Wednesday, September 21, 2005 10:45 PM
> > Subject: [AMRadio] Pi-Net vs Link Couple
> > 
> > > SO, here we are, well past 1991 and the 'law' that went into 
> effect
> > > saying that 1,500w PEP output is the maximum RF Power output 
> that we
> > > hams can run, regarldless of mode.  That doesn't deter the 
> homebrewing
> > > spirit, but it does suggest that acheiving 1,500w PEP output is 
> much
> > > easier than producing 1kW DC input to the final.  With the 
> mindset of
> > > still wanting to use the classic high-level plate modulation 
> scheme,
> > > engineering a rig to use only one tube in the final (a 4-250, 
> 250TH,
> > > 304TH/TL, 4-400, etc), modulated by a pair seems to make more 
> common
> > > sense.  That, and it's a bit more economic in filament 
> requirements.
> > >
> > > I've heard recently that matching the output of the Class C
> > > pate-modulated final to the antenna is better, and more 
> efficiently
> > > achieved by link coupling, vs Pi-Net.  On the other hand, it's 
> argued
> > > that Pi-Net coupling produces less RFI than link coupling does.
> > >
> > > So, which is better?
> > >
> > > Why?
> > >
> > > What are the effects of nuetralizing a single tube in a balanced 
> tank
> > > circuit?  If Pi-Net is to be used, does the final tube still 
> need to be
> > > nuetralized?
> > >
> > > I know of a guy who wants to build a rig using a single 450TL in 
> the
> > > final, modulated by a pair.  He wants to pi-net the output, but 
> I've
> > > heard that's a bad idea.
> > >
> > > I want to build a rig using a medium powered tride, perhaps a 
> 250TH,
> > > modulated by a pair of 811's.  Pi-Net, or Link Couple?
> > >
> > > I like seeing this kind of technical discussion on the list.  
> I'm
> > > looking forward to all inputs.
> > >
> > > --
> > > 73 = Best Regards,
> > > -Geoff/W5OMR
> > >
> > > ______________________________________________________________
> > > 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
> > > AMfone Website: http://www.amfone.net
> > > AM List Admin: Brian Sherrod/w5ami
> > >
> > 
> > ______________________________________________________________
> > 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
> > AMfone Website: http://www.amfone.net
> > AM List Admin: Brian Sherrod/w5ami
> ------- End of Original Message -------
> 
> 
> 
> ------------------------------
> 
> Message: 4
> Date: Thu, 22 Sep 2005 08:13:51 -0400
> From: Brett gazdzinski <Brett.gazdzinski at mci.com>
> Subject: RE: [AMRadio] Pi-Net vs Link Couple
> To: 'Discussion of AM Radio' <amradio at mailman.qth.net>
> Message-ID: <000801c5bf6f$1820e050$a5b220a6 at mcilink.com>
> Content-Type: text/plain; charset=US-ASCII
> 
> I don't think there is any way to run a triode single ended with 
> link
> coupled
> output, not in class C.
> 
> I run a pair of 812A's (or 811A's, or V70D's) push pull link coupled 
> output
> modulated by a pair of 811A's.
> It works very well.
> 
> You can run them up to 2000 volts on the plates, or 1750, 0r 1500.
> 
> I can get 400 watts carrier out pushing them, 350 watts out has the 
> tubes
> showing no color.
> 
> That is very close to the legal limit with plenty of audio.
> 
> The 812/811 tubes are cheap, work from 1000 to 2000 volts, and
> don't take up a lot of space.
> 
> I used small vacuum variable caps for neutralization, kilowatt
> coils, and a 6000 volt plate tuning cap.
> I got the small (2 to 30 pf @30,000 volts) neut caps out of old 
> paging 
> transmitters someone gave me, they ran a 4-400 at 3000 volts on 70? 
> MHZ.
> 
> Brett
> N2DTS
> 
> 
> 
> 
> 
> 
> -----Original Message-----
> From: amradio-bounces at mailman.qth.net
> [mailto:amradio-bounces at mailman.qth.net] On Behalf Of Geoff
> Sent: Wednesday, September 21, 2005 10:46 PM
> To: Discussion of AM Radio
> Subject: [AMRadio] Pi-Net vs Link Couple
> 
> 
> SO, here we are, well past 1991 and the 'law' that went into effect 
> 
> saying that 1,500w PEP output is the maximum RF Power output that we 
> 
> hams can run, regarldless of mode.  That doesn't deter the 
> homebrewing 
> spirit, but it does suggest that acheiving 1,500w PEP output is much 
> 
> easier than producing 1kW DC input to the final.  With the mindset 
> of 
> still wanting to use the classic high-level plate modulation scheme, 
> 
> engineering a rig to use only one tube in the final (a 4-250, 250TH, 
> 
> 304TH/TL, 4-400, etc), modulated by a pair seems to make more common 
> 
> sense.  That, and it's a bit more economic in filament 
> requirements.
> 
> I've heard recently that matching the output of the Class C 
> pate-modulated final to the antenna is better, and more efficiently 
> 
> achieved by link coupling, vs Pi-Net.  On the other hand, it's 
> argued 
> that Pi-Net coupling produces less RFI than link coupling does.
> 
> So, which is better?
> 
> Why?
> 
> What are the effects of nuetralizing a single tube in a balanced 
> tank 
> circuit?  If Pi-Net is to be used, does the final tube still need to 
> be 
> nuetralized?
> 
> I know of a guy who wants to build a rig using a single 450TL in the 
> 
> final, modulated by a pair.  He wants to pi-net the output, but I've 
> 
> heard that's a bad idea.
> 
> I want to build a rig using a medium powered tride, perhaps a 250TH, 
> 
> modulated by a pair of 811's.  Pi-Net, or Link Couple?
> 
> I like seeing this kind of technical discussion on the list.  I'm 
> looking forward to all inputs.
> 
> --
> 73 = Best Regards,
> -Geoff/W5OMR
> 
> ______________________________________________________________
> 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
> AMfone Website: http://www.amfone.net
> AM List Admin: Brian Sherrod/w5ami
> 
> 
> 
> ------------------------------
> 
> Message: 5
> Date: Thu, 22 Sep 2005 07:22:16 -0500
> From: Geoff <w5omr at satx.rr.com>
> Subject: Re: [AMRadio] Pi-Net vs Link Couple
> To: Discussion of AM Radio <amradio at mailman.qth.net>
> Message-ID: <4332A1F8.6000907 at satx.rr.com>
> Content-Type: text/plain; charset=us-ascii; format=flowed
> 
> ronnie.hull wrote:
> 
> > <>Mike I'm the fellow that is going to build up a Class C final 
> using 
> > a 450TL.
> > I would love to get a copy of that schematic for the 450TH rig in 
> the 
> > Editors
> > and Engineers handbook. I have a few of those, but apparently, not 
> 
> > that one.
> >
> > I have a very nice B&W 850A or 852 that I can use in this rig. 
> Either 
> > should
> > handle that tube fine, considering I'm not going to run much more 
> than 
> > 2500
> > volts on it anyway. Maybe 3000.
> >
> > I just got the worled biggest honker daddy plate transformer from 
> W5OMR.
> > 8200V center tapped ( 4100 - 0 - 4100 ) at 4.5KVA !!! Yeah suh, 
> takes 
> > 3 men
> > and a dolly to move it!!
> 
> 
> I think you're going to find, and we talked about this, that the 
> transformer is 4100v across the entire secondary (@4.74kVA)
> 
> 
> 
> 
> 
> 
> ------------------------------
> 
> Message: 6
> Date: Thu, 22 Sep 2005 08:41:26 -0400
> From: bcarling at cfl.rr.com
> Subject: Re: [AMRadio] Pi-Net vs Link Couple
> To: Discussion of AM Radio <amradio at mailman.qth.net>
> Message-ID: <43326E36.30967.CBCA1A at localhost>
> Content-Type: text/plain; charset=US-ASCII
> 
> On 22 Sep 2005 at 7:22, Geoff wrote:
> 
> > > I just got the worled biggest honker daddy plate transformer 
> from W5OMR.
> > > 8200V center tapped ( 4100 - 0 - 4100 ) at 4.5KVA !!
>  
> > I think you're going to find, and we talked about this, that the 
> > transformer is 4100v across the entire secondary (@4.74kVA)
> 
> Yeah but 8200 volts sounds so... electrifying!
> 
> If anyone needs a smaller tranny, I have one that will do 2500 volts 
> 
> at about 1 amp.
> 
> Brian, AF4K
> 
> 
> 
> 
> 
> ------------------------------
> 
> Message: 7
> Date: Thu, 22 Sep 2005 09:05:28 -0400
> From: "ronnie.hull" <ronnie.hull at glowbugs.com>
> Subject: Re: [AMRadio] Pi-Net vs Link Couple
> To: Discussion of AM Radio <amradio at mailman.qth.net>
> Message-ID: <20050922130528.M40836 at glowbugs.com>
> Content-Type: text/plain; charset=iso-8859-1
> 
> well it clearley shows on the top of the tranny 4100 - 0 - 4100.. 
> I'll test 
> it out this weekend and we'll know then.
> 
> did you ever even put power to this transformer?
> 
> R
> 
> 
> 
> ---------- Original Message -----------
> From: Geoff <w5omr at satx.rr.com>
> To: Discussion of AM Radio <amradio at mailman.qth.net>
> Sent: Thu, 22 Sep 2005 07:22:16 -0500
> Subject: Re: [AMRadio] Pi-Net vs Link Couple
> 
> > ronnie.hull wrote:
> > 
> > > <>Mike I'm the fellow that is going to build up a Class C final 
> using 
> > > a 450TL.
> > > I would love to get a copy of that schematic for the 450TH rig 
> in the 
> > > Editors
> > > and Engineers handbook. I have a few of those, but apparently, 
> not 
> > > that one.
> > >
> > > I have a very nice B&W 850A or 852 that I can use in this rig. 
> Either 
> > > should
> > > handle that tube fine, considering I'm not going to run much 
> more than 
> > > 2500
> > > volts on it anyway. Maybe 3000.
> > >
> > > I just got the worled biggest honker daddy plate transformer 
> from W5OMR.
> > > 8200V center tapped ( 4100 - 0 - 4100 ) at 4.5KVA !!! Yeah suh, 
> takes 
> > > 3 men
> > > and a dolly to move it!!
> > 
> > I think you're going to find, and we talked about this, that the 
> > transformer is 4100v across the entire secondary (@4.74kVA)
> > 
> > ______________________________________________________________
> > 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
> > AMfone Website: http://www.amfone.net
> > AM List Admin: Brian Sherrod/w5ami
> ------- End of Original Message -------
> 
> 
> 
> ------------------------------
> 
> Message: 8
> Date: Thu, 22 Sep 2005 09:06:33 -0400
> From: "ronnie.hull" <ronnie.hull at glowbugs.com>
> Subject: Re: [AMRadio] Pi-Net vs Link Couple
> To: Discussion of AM Radio <amradio at mailman.qth.net>
> Message-ID: <20050922130633.M99469 at glowbugs.com>
> Content-Type: text/plain; charset=iso-8859-1
> 
> well Bry, you gotta unnerstand, I'm next door to Texas, that makes 
> me a 
> cousin.. and you know how they are in texas.. everything is 
> bigger!!!
> 
> R
> 
> 
> 
> ---------- Original Message -----------
> From: bcarling at cfl.rr.com
> To: Discussion of AM Radio <amradio at mailman.qth.net>
> Sent: Thu, 22 Sep 2005 08:41:26 -0400
> Subject: Re: [AMRadio] Pi-Net vs Link Couple
> 
> > On 22 Sep 2005 at 7:22, Geoff wrote:
> > 
> > > > I just got the worled biggest honker daddy plate transformer 
> from 
> W5OMR.
> > > > 8200V center tapped ( 4100 - 0 - 4100 ) at 4.5KVA !!
> >  
> > > I think you're going to find, and we talked about this, that the 
> 
> > > transformer is 4100v across the entire secondary (@4.74kVA)
> > 
> > Yeah but 8200 volts sounds so... electrifying!
> > 
> > If anyone needs a smaller tranny, I have one that will do 2500 
> volts 
> > at about 1 amp.
> > 
> > Brian, AF4K
> > 
> > ______________________________________________________________
> > 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
> > AMfone Website: http://www.amfone.net
> > AM List Admin: Brian Sherrod/w5ami
> ------- End of Original Message -------
> 
> 
> 
> ------------------------------
> 
> Message: 9
> Date: Thu, 22 Sep 2005 09:01:35 -0500
> From: Geoff <w5omr at satx.rr.com>
> Subject: Re: [AMRadio] Pi-Net vs Link Couple
> To: Discussion of AM Radio <amradio at mailman.qth.net>
> Message-ID: <4332B93F.6090008 at satx.rr.com>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
> 
> ronnie.hull wrote:
> 
> > <>well it clearley shows on the top of the tranny 4100 - 0 - 
> 4100.. 
> > I'll test
> > it out this weekend and we'll know then.
> >
> > did you ever even put power to this transformer?
> >
> > R
> 
> 
> Yes, I did.  Did it at John/WA5BXO's place.
> 
> 
> 
> 
> 
> ------------------------------
> 
> Message: 10
> Date: Thu, 22 Sep 2005 09:03:49 -0500
> From: Geoff <w5omr at satx.rr.com>
> Subject: Re: [AMRadio] Pi-Net vs Link Couple
> To: Discussion of AM Radio <amradio at mailman.qth.net>
> Message-ID: <4332B9C5.4060507 at satx.rr.com>
> Content-Type: text/plain; charset=us-ascii; format=flowed
> 
> ronnie.hull wrote:
> 
> > <>well Bry, you gotta unnerstand, I'm next door to Texas, that 
> makes me a
> > cousin.. and you know how they are in texas.. everything is 
> bigger!!!
> >
> > R
> 
> 
> Bry, just on the Off-chance that I might make it to Florida, what 
> are 
> you asking for that 2500v @ 1amp xfmr?
> 
> --
> 73 = Best Regards,
> -Geoff/W5OMR
> 
> 
> 
> 
> ------------------------------
> 
> ______________________________________________________________
> 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 20, Issue 33
> ***************************************
> 
> 



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