[Hammarlund] HQ-180 Noise blanker

[JM/CO]

The "normal" noise limiter is an ( at best ) rather crude diode limiter
device which acts in the audio circuit, just post IF stages. This type of
circuit was used in Comm. receivers since the early days, and works
basically by clipping the tips off spikes that get through the IF amps. The
"optional" noise limiter that you refer to becomes a part of the IF stages.
I have both of these in my HQ-180. The results are somewhat different. The
IF limiter is definitely an improvement. By the way, if you should happen to
acquire a radio that has had this unit installed ( it sits atop the
bandspread variable cap assembly ) be sure to "lower" it before attempting
to remove the receiver chassis from it's cabinet. Failure to do this will
result in a severely damaged IF can on the limiter chassis. Ask me how I
know<G>.
Chuck N1LNH
----- Original Message -----
From: <R390rcvr@aol.com>
To: <hammarlund@mailman.qth.net>
Sent: Saturday, November 30, 2002 8:43 PM
Subject: [Hammarlund] HQ-180 Noise blanker


> Good evening all:
>
> Has anyone had any experience with the optional noise blanker for the
> HQ-170/180?
>
> I am curious how much of an improvement it is over a traditional noise
> limiter.
>
> Thanks
>
> Randy Stout
>
>
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