Re: {Collins} 51J4/CV591A Interfacing

----- Original Message ----- From: "Ted Hartson" <awombat@xxxxxxxxxxxxx> To: "Wally Klinger" <wklinn@xxxxxxxxxxx>; "Collins Listserver" <collins@xxxxxxxxxxxxx>
Sent: Friday, July 22, 2011 10:57 AM
Subject: Re: {Collins} 51J4/CV591A Interfacing

I have used CV-591s on 'J3/4s years ago. It is a matter of tuning the variable network to 500 kHz changing silver micas as I recall. The preset crystals will also have to be changed if you desire that feature. The 591 had some strange dc voltage applied to the audio line to tune the vfo, I would kill that. The J3/4 series has a rather unpopular property of inverting USB/LSB on every other MHz band . When CV-591s cost $10 and were plentiful these changes were not a big deal. Now I see these units sell for hundreds on the Bay. For my money I would get the Canadian Treetop (or what ever) plug in that is for sale also on the Bay for about $75, less effort and great performance

It is Treetop Circuits at They have the instruction book on line as a PDF so you can see what is required to install it. Some surgery is required but not much. The device provides an advanced product detector and excellent AVC. With it the 51J-4 should become an outstanding SSB receiver. Even a 51J-3/R-388 becomes a very good SSB receiver, the only shortcoming being lack of selectivity. Both work very well on CW. I prefer the older cryatal filter for CW and its still there on the J4. I think this is a much better approach than an outboard SSB converter.

Richard Knoppow
Los Angeles

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