----- Original Message -----
From: "Gary Poland" <gpola...@cinci.rr.com>
To: <drakelist@zerobeat.net>
Sent: Sunday, February 06, 2011 2:09 PM
Subject: Re: [Drakelist] What is he best way to test the
N-4B noise blanker?
Anything with brushes, a corless drill, heat gun, etc.
Also a solder station with adjustable heat works great.
73, Gary
Something that works and is simple is to use an ohm
meter on its highest setting. This works especially well
with older meters that have high voltage batteries for the
highest resistance range. Just clip one end of the meter to
the antenna connector and tap it with the other lead. That
makes a large, high level, click. A series of taps applied
to my R-388, which as a slow AVC mod but no blanker,
desensitized it running the S-meter to a high level.
Although the noise limiter removes the clicking it does not
help with the AVC problem. On my Drake R-4B the same thing
happens in either fast or slow AVC without the blanker on,
that is, the AVC desensitizes the reveiver. The Blanker
pretty much eliminates this. While there is still some rise
of the S-meter and reduction of background noise, it is very
much less than when the blanker is turned off.
Note that this is the purpose of the blanker, its not
effective on power line hash, which a plain limiter will
reduce but, since it comes before the AVC detector, its
quite effective in eliminating the desensitizing effect.
I never hear ignition noise except in my own car when
listening to very weak stations. I guess modern ignition
systems has pretty much eliminated it.
--
Richard Knoppow
Los Angeles
WB6KBL
dickb...@ix.netcom.com
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