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[TowerTalk] Powerline noise-Timewave ANC-4

To: <towertalk@contesting.com>
Subject: [TowerTalk] Powerline noise-Timewave ANC-4
From: W8JI@contesting.com (Tom Rauch)
Date: Fri, 2 Nov 2001 09:57:11 -0500
> Has anyone used the ANC-4 antenna noise canceller.....does it REALLY
> work?

The ANC4 as well as the MFJ1025 noise canceller might work. 

These units are really variable phase shift networks with amplitude 
controls and a combiner. What they do is combine the signals from 
two input ports after one channel is shifted in phase.

What you do is install a noise antenna as close to the noise 
source as you can, and phase it against your main antenna. You 
can also use this unit to phase two antennas together for receiving, 
and add desired signals to make them stronger or null unwanted 
signals.

If you hear the same noise bothering you on your main antenna 
clearly on the noise antenna, you can get a real deep null. 50-60 
dB is not unusual for the null of a groundwave signal.

If noise or QRM comes from multiple sources, or changes 
directions or angles, the nulling effect can be much less dramatic.  

The MFJ is certainly the better unit of the two. The MFJ unit has 
much better amplitude stability when you adjust phase, and more 
phase adjustment range. I used a homebrew enhanced version of 
the MFJ for years to phase receiving antennas, and to tell the 
direction of incoming signals.
73, Tom W8JI
W8JI@contesting.com 

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