On Wed, 2 Nov 2011, Edward Knobloch wrote:
My receiver required a realignment to get back the very sharp
selectivity designed into it. The audio system has a strange
design, where the level you set the gain control also affects
the audio bandwidth. If the audio is cranked up high,
for weak signal reception, audio bandwidth will be reduced.
It never bothered me, but it is something to be aware of.


On 11/2/2011 2:12 PM, Michael Black wrote:
Is that the "variable response audio system" mentioned in the "73"
listing? I read the listing as meaning "tone control".



Hi, Michael

No, there is no separate "tone control" with the HQ-170 receiver,
just the strange variable audio bandwidth circuit thru the AF gain pot.

There's a note on how to remove that HQ-170 "feature",
and add fixed negative feedback around the audio section
to reduce distortion, by Larry W9MDX, included he

http://bama.edebris.com/manuals/hammarlu/hq170notes/

73,
Ed Knobloch