[TowerTalk] Balun for older Cushcraft 402CD

[Richard Thorne]

Jim

Good points.

It reminded me that my original post was for tribanders.  The 1116 would 
be a better choice for 40m.

Rich - N5ZC

On 1/19/2018 12:06 PM, Jim Thomson wrote:
> Date: Fri, 19 Jan 2018 06:47:25 -0600
> From: Richard Thorne <rthorne at rthorne.net>
> To: towertalk at 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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