Topband: Fwd: TX/RX Antenna Switching

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---------- Forwarded message ----------
From: Herb Schoenbohm <herbs at vitelcom.net>
Date: Thu, Nov 15, 2012 at 5:22 PM

I used to use at first the MFJ-1026 Noise Canceller/Phaser box in a
reverse configuration to bring the RX only antennas in from the Beverage
bank.  With the RF sense switch there were problems with the leading
edge on higher speed CW being cut.  This was solved by using the forced
12 available from a small relay box in line with the amp keying line, as
my Icom does not provide 12 VDC out on key down only 8VDC at a few
mills.  About a year later I purchased the RTR-1 by DXE and this is
really the way to go.

As Tom, W8JI pointed out on an earlier article on his website, there are
several improvements that can be made to the MFJ unit to reduce the
noise figure on the RX port but I just use them now to phase Beverages
primarily for noise cancellation from unwanted directions.  This may
help in some circumstances but the tuning in the MFJ is very critical
and not something you can do well during the heat of a contest during
peaking mode.  So I just set things up in advance for one path and two
Beverages such as Europe but that to can change radically the longest
distance signals which can shift here from 20 to 90 degrees at times
depending on what is happening at the north pole.


Herb, KV4FZ