[VHFcontesting] Need help with Cushcraft A50-3S - high SWR

Eric Watkins shelshok at comcast.net
Tue Mar 6 17:39:08 PST 2012

Some years ago, I too bought a Cushcraft 6mtr beam. I've since fixed 
that by buying just about anything else. Their stuff might have been 
good back in the day, but it seems to have taken a nose dive as far 
as quality goes, as you said, they are now owned by MFJ so go figure. 
I've since moved to an Arrow Antenna 3el beam that is far easier to 
put together, easier to troubleshoot and comes matched out of the 
box. Cushcraft SWR problems solved. If I was going to buy a 5 el beam 
I'd consider an M2 unit since Arrow doesn't sell a longer 6m beam. 
Cut your time losses and buy an antenna that isn't made of 300+ 
parts. All those little nuts, bolts and washers are a nightmare to 
keep on the beam, long term. Do not want to insult you, but take a 
look at returning it and buying something with fewer parts and a 
better service record.

73s kr0ver

At 07:00 AM 3/6/2012, beamar wrote:
>Some years ago, I bought a 5 element M2 6M yaghi. I had the same 
>problem that you are having. What I did was really stupid and it is 
>taking a lot of courage to publicly admit my mistake: I assembled 
>the antenna backwards. That is, I had the last director in the 
>reflector hole and the reflector in the last director hole. I stood 
>there and looked at the antenna. It looked kind of funny. I got out 
>the tape measure. When I put the elements in the right holes in the 
>boom, the SWR went right down. Do not want to insult you, but take a 
>look before you start replacing the matching section, etc.
>Buddy Morgan WB4OMG
>On Mar 5, 2012, at 3:50:14 PM, ejh <wm3m at live.com> wrote:
>From:   ejh <wm3m at live.com>
>Subject:        [VHFcontesting] Need help with Cushcraft A50-3S - high SWR
>Date:   March 5, 2012 3:50:14 PM EST
>To:     vhfcontesting at contesting.com
>I have a new Cushcraft A50-3S, 6 mtr beam, and I am having trouble 
>getting the SWRs down.
>I measured multiple times the element lengths and set them to the 50 
>Mhz sizes.
>I then set the gamma match to the exact sizes shown in the manual, 
>(set and X) but even installed on my roof away from all objects the 
>SWR was very high, way too high for my transceivers. I kept 
>adjusting the gamma match and the only way I could get SWRs down low 
>enough to work with my rigs was to make it as short as possible with 
>the small rod pushed all the way inside the larger rod. But even 
>then the SWRs were well above 2 at 50.125 mhz? I have worked with it 
>for many hours and I am unable to figure out how to adjust the gamma 
>match correctly.
>This is replacement for a damaged A50-3 I had for years, did not 
>have problems with the old one. The gamma match on the new one is 
>different, on the new gamma match the small rod does not make 
>contact with the larger tube it slides into. I tried two different, 
>new lmr-400 coax runs, no change.
>I sent email to Cushcraft/MFJ but they have not answers previous 
>emails, so don?t suspect I will hear from them. Any help would be 
>appreciated. Thanks
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