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 ______________________________________________________________ R-390 mailing list Home: http://mailman.qth.net/mailman/listinfo/r-390 Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
