Paul and Jim,
The Cushcraft MA5V was designed by K1BQT, Rick Littlefield and he calls it
an "Off Center Fed Dipole). In the Jan/Feb 2002 issue of QEX, page 54, is a
complete technical write up on same.
I believe the coax in the isolator is RG58 (not RG59). Beware, this is a
low power antenna and is only specified to handle 250 Watts PEP SSB!
At 07:35 PM 1/28/2003 -0700, Jim Harris wrote:
>I put up the same antenna about a month ago. The hardware on mine was in
>fine shape......no problems at all. The balun is just as you mentioned
>imho. The radials in my estimation are too small and the balun is to keep
>RF from coming back down the coax shield. Looks to me like the coax for
>the balun was of okay quality.
>The big problem I had was that the band width on 20 & 12 meters is skewed
>towards towards the lower part of the band and there are no adjustment
>procedures. Have to use a tuner on the upper part of the band. Looks
>like just shorten the studs on the ends of the coils to raise the center
>of the bandwidth. Not a clue anywhere as to how much to shorten
>them. Know where I can get a mfj-259 cheap. Hi!
>It does play a bit better than a carolina windom I've had up a
>while....and, seem liek it does DX much better.
>>I recently put up a Cushcraft MA5V vertical for HF satellite work. The
>>antenna is working ok- but since I can not find a human to speak to at
>>Cushcraft, or anyone there to return emails, I have a question about the
>>antenna design that maybe someone here can answer. If you look at a
>>photo of the antenna, you'll notice a very large coaxial balun at the
>>bottom of the antenna PVC support. The PVC isolates the antenna which
>>sits about about 4 feet above the balun feedpoint, and the balun is at
>>the bottom of the PVC support- - The balun form is about 2 3/8 inches in
>>diameter, 10 1/2 inches long, and it takes about 30 feet of RG59 coax
>>twisted around the form to create the balun.......what's with this
>>monster balun?? What is it doing??
>>I've never seen anything like it before- MY guess is that it is overkill
>>to keep RF off the feed line- ??? Any thoughts on this?
>>BTW, the QC at Cushcraft is awful...I had to redrill, rebuild, and modify
>>a lot of missing and/or misized parts- Blah! And the enclosed RG59 to
>>form the balun is rat shack junk- But the antenna is working
>>FB! Seriously, it's working well above expectations-
>>73 Paul N0AH
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