>From: AB5MM <firstname.lastname@example.org>
I never had any problems with my MFJ-259B when tuning my old Butternut HV-2
vertical on 80 and 160 meters, but when I tried to get readings from a
newer insulated 50 feet of Rohn 25 with a 14-foot stinger with about 60
radials (of mixed length between 60 and 120 feet), I also got answers that
looked wrong---and they were wrong for reasons that have been suggested by
others (one day I hooked the antenna to the input of my 100MHz scope and
could see lots of hash from all of the RF on the antenna, even though the
nearest BC station is more than 10 miles away and not terribly high power).
At the suggestion of several on this reflector, I got an MFJ-731 Analyzer
Filter. The manual is at
The filter works. It is not as convenient, because the filter has to be
adjusted for each frequency, but with it, the MFJ-259B seems to give
reasonably accurate readings. I was even able to back out the correct sign
of the reactive component by taking readings at close-by frequencies. I
then used the measured impedance readings to design L networks for both 80
and 160 meters and both were spot-on.
Because of all the bottom loading I do not have great bandwidth on 160, but
it sure is lots better than it used to be with the old HV-2. Seems to get
out better too.
>Subject: [TowerTalk] 160m 1/4 Wave Vertical Results Thus Far...
>Date: Thu, 27 Sep 2007 19:51:38 -0500
>2. Both the MFJ-249 and MFJ-259B are virtually useless at these
>frequencies. Too much rf from the BC band. This alone would have saved us
>hours in trying various matching networks, not to mention the number of
>"Pepcid Complete" ingested.
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