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Re: [Amps] stereo to mono

To: "Rob Atkinson" <>, <>
Subject: Re: [Amps] stereo to mono
From: "Carl" <>
Date: Sun, 9 May 2010 11:31:32 -0400
List-post: <">>
While the various post WW2 handbooks up into the late 60's carry plenty of 
circuits and some design info they all concentrate on space shuttle audio. 
Many 30's designs are full of distortion and other problems, post war were 
the golden years. The West Coast and properly called the Editors and 
Engineers and later the Bill Orr HB are by far superior to the ARRL which 
repeated the same circuits for decades. The Orr series went into formulas 
for detemining transformer requirements for tubes and/or conditions that 
werent in tube manuals.

Probably the biggest AM interest is restoring commercial ham and military 
transmitters and modifying for better fidelity. (The BC-610, ART-13, TCS has 
become as popular as it was in the past.) Some take it to extremes. Even 
Heath and other carrier control rigs are popular as most of the heavy plate 
modulated rigs are getting real pricey. Others are converting old AM BCB 
rigs to various lower ham bands.

The homebrew Rob mentioned goes from 10-20W up to 450TL's, 4-1000A, 3CX3000, 
etc. The biggest problem for QRO is finding and/or affording modulation 
transformers. I couldnt find a 1000-1500W transformer for under a mortgage 
payment and wound up with a 7500W oil filled for considerably less. It helps 
hold down the basement floor when the rains come (-; The orange glowing PP 
304TL's dont even faze it.

Get on 40 some evenings, several with yagis regularly work DX, same on 20. 
When 10 or 6 is open it can be a blast. Ive even had QSO's on 12, 15, and 

If you hear me, stop and say hi, most rice box rigs sound almost good on AM 
when set up properly. They still sound bad on Slop Bucket (-;

AM 160-2M
SSB/CW 160 to 10gHz

----- Original Message ----- 
From: "Rob Atkinson" <>
To: <>
Sent: Sunday, May 09, 2010 10:29 AM
Subject: Re: [Amps] stereo to mono

> <<<We HAMS have not been building high level modulated A.M. transmitters 
> for
> many years (A.M. transmissions suffer from heterodyne interference
> which becomes horrific in a
> crowded HAM band) so I recommend you refer to HAM handbooks dated from
> the late 1940s to 1970 or so
> for more information about high level modulated transmitters.>>>
> Ron,
> You could not be more wrong.  Homebrewing high level plate modulated
> AM rigs is alive and well.
> In fact, it is becoming more popular.  You obviously are unaware of
> this development perhaps because you do not read the right journal and
> do not visit the websites dedicated to AM.
> I invite you to subscribe to Electric Radio, and visit
> one of the many websites dedicated to AM. is a good
> place to start.
> You are correct with regard to the old handbooks, which are a valuable
> resource among AMers, especially the ones published before WW2.
> There is also growing interest in Class E AM, with solid state rigs.
> K7DYY makes and sells a 300 w. kit solid state AM rig.  AM is
> exceedingly enjoyable and I invite you to give it a try.  All you need
> to start with is any transceiver that includes it as a mode.
> 73
> Rob
> K5UJ
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