At 08:36 AM 11/8/96 -0600, you wrote:
> A local station recently purchased a couple of the M2 3 element 40
> meter antennas. We were impressed with the antennas while we were
> putting them together...things fit well, nicely machined parts, etc.
>
> However, they've been up now for about four weeks and problems have
> developed. The SWR on the antennas is all over the place. While the
> SWR varies somewhat in windy conditions (to be expected), the antennas
> show widely varying SWR from day to day. The antennas' SWR are
> normally about 1.6 at the bottom of the band. As you go up in
> frequency, they go to 1:1, then rise. (again, as you would expect).
> However, on some days they're flat across most of the band...other days
> they start out at 3:1 at the bottom of the band, drop to about 2:1 at
> 7040, then going up from there. We've also seen the SWR take quick
> "jumps" which would seem to imply problems with electrical/mechanical
> connections.
>
> We have pulled down the antennas and examined them closely (several
> times). We found that the set screws which hold the linear loading
> rods had worked lose. After talking with M2, we've tried various
> arrangments on the set screws including double set screws (one to lock
> the other in place), stainless steel machine screws with locking nuts,
> etc. None of these solutions have held up more than a few days.
>
> A good connection with the linear loading rods is obviously crucial to
> the operation of the antenna. Anyone out there have similar problems
> with the large M2 antennas which use linear loading?? Any solutions??
>
> We haven't really gotten any good solutions yet from M2.
>
> 73,
>
> Dave
> WA0FLS
>
>
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>
>Hi Dave, I had a similiar experience. I purchased their 4el 20m yagi
along with another element to make it a 5el 20 and used my measurments etc.
I had a lot of problems with their T-Match and the set screws that they
used. They would create groves in the solid 1/4 inch rod, and caused
erratic swr etc. Mine was first noticed on receive and while runing low
power. I believe the groves in the rod were caused by the
driven element flexing etc. I wrote Mike a couple of times and he never
responded.
This year at Dayton I approached him and advised him that I had completely
removed his T-Match and made one of my own. Their rods and set screw
arrangements are no good and I told him that. Wish I could tell you how to
fix it. It really is a shame Mike does not change his T-Match and set screw
arrangement. The rest of his antenna hardware I believe is the best on the
market. GL 72 Pete N4KW
--
FAQ on WWW: http://www.contesting.com/towertalkfaq.html
Submissions: towertalk@contesting.com
Administrative requests: towertalk-REQUEST@contesting.com
Problems: K7LXC@contesting.com
Sponsored by Akorn Access, Inc & KM9P
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