[ARC5] Using a power transformers as a modulation transformer.

[Glen Zook]

When I used the power transformer as a modulation transformer was over 50-years ago.  I was like 15 at the time and really didn't know better!  No modification of the transformer was done.  I was using a pair of 807 tubes modulating another pair of 807 tubes (Globe Chief 90A).  This arrangement was used for about a year until I obtained a used Heath DX-100.  The signal reports were always good and a number of stations commented on how well the transmitter "sounded".

The modulator was built on an old television chassis and all of the lower stage tubes were octal, not miniature, tubes.  I don't remember just what tubes I did use.  One thing about the modulator was that there was a blue glow around the elements themselves that varied with modulation.  One of my amateur radio operator friends, who attended the same high school as I, used to like to watch these blue glowing elements as I modulated the transmitter.
 
Glen, K9STH


Website:  http://k9sth.com


________________________________
 From: J. Forster <jfor at quikus.com>
To: Glen Zook <gzook at yahoo.com> 
Cc: Leslie Smith <vk2bcu at operamail.com>; ARC-5 List <arc5 at mailman.qth.net> 
Sent: Friday, April 12, 2013 7:33 PM
Subject: Re: [ARC5] Using a power transformers as a modulation transformer.
 

Glen,

The current capability is not the issue. The DC component of the final
saturated the iron in the core.

That's why a previous poster suggested restacking the E-Is to permit an
air gap.