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Re: [Amps] stereo to mono

To: Carl <>
Subject: Re: [Amps] stereo to mono
From: Rob Atkinson <>
Date: Sun, 9 May 2010 11:19:13 -0500
List-post: <">>
In addition to Carl's excellent comment, I'd like to mention my source
of last resort for used books.

If you can't find the Orr or other handbook at a hamfest (Dayton
coming up is a pretty good place to look) go to

I got my Orr 17 ed. handbook there (a superior AM resource compared to
the ARRL books) and also my Terman Radio Engineer's Handbook (1st ed.
1943 McGraw Hill).

Any book on radio by Frederick Terman is a gold mine.  It is usually
possible to find a good copy of something at abebooks for a reasonable


On Sun, May 9, 2010 at 10:31 AM, Carl <> wrote:
> 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
> 17M.
> 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 (-;
> Carl
> KM1H
> 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
>> _______________________________________________
>> Amps mailing list
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