[Hammarlund] HQ-180/HQ-170A audio comparison video - AGC issues

[Kenneth G. Gordon]

Robert:

I just thought of another matter concerning your 180 and its AGC: in a very 
recent issue of Electric Radio Magazine, an author modified the AGC 
circuitry of both a Hammarlund HQ-180 and a Heathkit Mohawk receiver in 
the same way, which achieved a considerable improvement in the way both 
receivers sounded.

Examining the schematics of both receivers, he discovered that certain 
stages in both receivers did NOT have AGC connected to them, which, it 
was quite obvious, SHOULD have.

He connected these uncontrolled stages to the AGC buss without making 
any other changes and the results were quite dramatic in that the harsh 
sounding audio from both SSB and CW signals was dramatically improved.

The post from Byron Tatum says very much the same thing, but Byron 
includes other improvements, one of which, the improvement of the AGC 
attack time, is, in my opinion, very important.

I think that if you were to incorporate those suggestions from the Electric 
Radio Magazine article, and those mentioned by Byron, your problems with 
the 180 would be pretty much solved.

You may wish to review all these suggestions then incorporate those which 
seemed most useful to you.

Ken W7EKB