On Aug 31, 9:40 am, "Harold E. Johnson" wrote:
Which Year One was that, Harold? Where I became a ham many years
back, there was a creative fellow in our club who designed a compact
AM transmitter using a couple 6146s, one for the RF PA and one for the
audio output. They were coupled not by a choke as in Heising, but by
a common audio output transformer, available back then much more
readily than a modulation transformer, and having the advantage that
the DC in the center-tapped winding was (nearly) balanced, avoiding
saturation effects in the transformer and allowing the use of a
relatively small transformer. I think Mitch designed that thing in
the mid 50's.

Cheers,
Tom

Hi Tom. Must have been around 1954, cause I'm sure it was after I came back
from Sunny Athens Greece. (SV0WX) I have the complete QST on disk, if you'd
like to peruse the article, I can go find it for you.

(Yes, and there was another one. Mobile Tube rig, winding up in a 10 Watt
2E26 I think, with something like a 25 Watt transistor audio amplifier for a
modulator. Part of THAT was rectified and used for the B+ for the rig. I
started on building that and then found a vibrator supply.)

Regards
W4ZCB

Oh, the good old days when you could mention vibrators in polite
company and not get odd looks, and when the whir of a dynamotor likely
meant someone had keyed up to transmit.

I suppose Mitch got some of his ideas from articles in that era, but
for sure the design was his own, with quite a few innovations as far
as anyone around there knew.

No need to look any of the old QST stuff up for me. I'm too busy
having fun with all this new-fangled stuff, trying to get IIP3s above--
well, above some pretty large numbers.

Cheers,
Tom