Date: Fri, 19 Jan 2018 06:47:25 -0600
From: Richard Thorne <rthorne@rthorne.net>
To: towertalk@contesting.com
Subject: Re: [TowerTalk] Balun for older Cushcraft 402CD
<Dave,
<Go with a a balun designs? ( balundesigns.com ) 1115d with the studs on
<top.? Go from the balun studs to the element halves with a length of
<wire and ring terminals crimped/soldered.
<For mounting the balun to the boom order the BMP1 balun mounting plate.?
<Nice and easy and clean, no tape needed other than attaching the coax to
<the boom.
<I just replaced a F12 balun (cal-av labs I believe) on my C31.? This was
<the 3rd F12 balun to fail.? They short out for some reason.? JK Antennas
<who now builds F12 antennas also uses Balun Design baluns.
<Every one of my antennas now uses a 1115d balun and not a single problem.
<Rich – N5ZC
## For his 40M MONOBAND yagi, a better choice would be the
Balun designs 1116D. > 6300 ohms..... vs the 5200 ohms of
the model 115D.
## My big problem with the balun designs CM baluns is.... their graphs
only depict RS, XS, RP for the resonant freq only! Thats only telling
folks
a very small part of the story. Ideally you want RP to be very high in
value. You also want
RS to also be high in value, like 90-100 % of RP. In all cases, you want RS
to be
higher than XP. Since they only depict RS, XS, RP at ONE freq, they are not
telling you the full story.
Ideally, they should be graphing RS vs freq, XS vs freq, and RP vs freq.
Only then do you have
enough info to evaluate the CM choke.
## Their model 1115D resonates at 14.40892 mhz
Their model 1116D resonates at 4.75734 mhz
Jim VE7RF
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