[R-390] Improving Lee Prod Det and SSB AGC mods

[Larry H]

Jacques Fortin pointed out (in a post on the R-390 forum on 7-8-2022)
that W7DI wrote an improved variant of the Capt. Paul Lee W3JHR product
detector using a relay to switch the audio.  His article is in the July
1974 issue of Ham Radio on page 14 (there is a link to the Ham Radio
magazines on our website).  I like the article quite well and wish I had
seen it before I did my product detector mod.  Jacques also pointed out a
better way to power the relay and found a miniature spdt one that works.
For more details, see my document here: Improving Lee Prod Det and SSB
AGC.pdf (r-390a.net)
<https://r-390a.net/Improving%20Lee%20Prod%20Det%20and%20SSB%20AGC.pdf>.
Thank you Jacques.

I found a miniature dpdt (for $0.20 more) that will not only switch the
audio, but I will also switch the AGC (and improve it).  I’m not totally
satisfied with the Dr. Langford AGC mods, so this will allow it to work
differently and more correctly for AM and SSB. I’m posting this now because
if you’re considering doing this mod you may want to get the dpdt relay
instead.

for more  information about the relays and ordering info, see my
article link above.

I've received and tested the dpdt relay and designed the next AGC mod
to use 1/2 of it, I just need to get my daily driver on the bench.

Stay tuned.

Regards, Larry