[Hammarlund] Bob Camp-HQ180

Roy Morgan roy.morgan at nist.gov
Thu Apr 21 09:32:40 EDT 2005


At 09:53 PM 4/19/2005, Mike Taylor wrote:
>Robert, are you suggesting that I put a 3.2 ohm resistor in series between
>the HQ-180 and the stereo pre-amp input? Or perhaps in parralell?

Mike,

In Parallel makes more sense.

>... Robert's not thrilled with the audio from his HQ-180 and neither
>am I. Over the last three years, several others have stated the same thing.

The problems are:

1) the fact that the LOW IF has a restricted bandwidth.  Apparently stagger 
tuning the low IF can help, (I have not done it yet on the HQ-170 I'm 
working on.)

2) The HQ-170 and 180 have an odd feedback/volume system that increases 
high frequency response as you turn the volume up.  The cure is to get rid 
of that circuitry and add normal negative feedback to bring the system gain 
back down and to increase audio bandwidth.

Roy

- Roy Morgan, K1LKY since 1959 - Keep 'em Glowing!
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