I use a remote tuned Vactrol to adjust the terminating resistance of one of
my pennants. It does make a difference. I have a pot by my receiver that I
adjust for best F/B for 3.5, 3.8 and 160M. When I set up the Vactrol, I used
a signal on a short vertical directly behind the pennant by about 50'. I
fed the vertical with an MFJ Antenna Analyzer. I hooked up a receiver to the
feed point of the pennant. I adjusted the Vactrol for the lowest s-meter
reading on the receiver for 3.5, 3.8 and 1.84. The terminating value for the
3 frequencies varied from about 750 - 1100 ohms.
Can I hear a difference? Most of the time no or not much. But there have
been times trying to pull out a weak one where adjusting the Vactrol made
all the difference in the world.
[mailto:firstname.lastname@example.org]On Behalf Of Jepilot@aol.com
Sent: Monday, August 04, 2003 15:42
Subject: [TowerTalk] K9AY receiving loop antenna
A Google search has resulted in two sources for the indoor control box and
the outdoor direction-switching relay box used for the K9AY four direction
receiving loop antenna system.
WX0B offers the indoor control box and outdoor switching box and a
purchased termination resistor (fixed value). This system allows four
directions to be selected.
Wellbrook Communications in England offers the same two boxes but with some
interesting improvements (I presume these changes are in fact improvements).
The Wellbrook units incorporate a remote controlled variable termination
feature which apparently allows adjustment of the value of the outdoor
resistor to obtain the best result for the soil conditions at your location
allows adjustment as your local soil conditions change as a result of rain,
Also the Wellbrook system incorporates what is described as a rotary beam
direction control which allows you to fine tune the favored direction for
best result instead of having only 4 fixed directions for selection as used
the original article by K9AY and used for the WX0B system.
So, has anyone used the Wellbrook system? Is the variable termination
feature worthwhile? Is the rotary direction control feature worthwhile or
The cost of the Wellbrook including shipping is about 300 British pounds
which is about $500 US depending on the pound/dollar exchange rate. This
quite a bit more than the price for the WX0B system.
All comments are welcomed. Thanks es 73
Jan Rehler, W5KNZ, Corpus Christi, Texas
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless
Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any
questions and ask for Sherman, W2FLA.
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