[R-390] REALLY SNAZZY AGC mod for R-390A

[Kenneth G. Gordon]

On 10 Mar 2007 at 12:18, Straugh wrote:

> Hi Ken;
> I've seen the articles and I have the receivers but I need to talk
> with someone who has actually done the mod.

I would suggest talking with Ray Osterwald, N0DMS. He is not only the 
editor of ER, but is a very competent tech and VERY easy to talk with.

The telephone number for ER is on their website at:

http://www.ermag.com/

> One of my receivers was
> modified with what was to have been the best of the best mod but it
> works after a fashion with all the AGC and then some.

I don't understand this statement. Sorry. 

I DO know that there have been many, many attempts to incorporate a 
really excellent AGC into the R-390 series. Some work better than 
others, some aren't really any better than the original, and some are 
actually worse. However, Clark Hatch's appears to be a real winner.

> 
> I use 390As. in fact I got rid of my 51j-4 and the R-725 beats it hand
> down. Question is have you modified any units relative to the two
> articles involved?

Not yet, but Clark's is certainly on my list. I have a really excellent R-
390A which one of our list members sort of traded to me a while back, 
which I have never yet turned on since I don't want to lose any filters.

I intend for that one to become my main station receiver.

Now, many years ago, I DID modify the AGC system in an R-390A to 
my satisfaction for use when doing AFMARS phone patching into 
Vietnam, and I have also modified an R-390 by adding a triode product 
detector to it. I used 1/2 of that dual triode which ordinarily feeds the IF 
out to a jack on the back, so I didn't add any holes or extra tubes.

It made a big difference in recovered audio and signal-to-noise ratio on 
SSB.

Ken Gordon W7EKB