On Wed, 26 Aug 1998 15:12:08 -0700 Tom Osborne <w7why@mail.coos.or.us>
writes:
>
>HI all
>Last night I was talking to a friend, NO7F/KL7, and he was wondering
>about changing a TH-6 to a TH-3. He's on Unalaska Island, and the
>winds
>get up to 160 MPH there and he thinks he would be better off with a
>smaller beam. Has anyone ever done this? If you have any info, you
>could E-mail him directly at ttim@arctic.net. Thanks and 73
>Tom W7WHY
>
If the winds really do get to 160 MPH, I doubt if ANY conventional
amateur antenna would survive. At that wind speed the ELEMENTS
will break so boom length would not make much difference. The
BEST amateur antennas are rated for 100MPH with some beefed
up versions for maybe 120 MPH. I have never heard of any Yagi
antenna rated for 160 MPH. At those speeds, keeping the tower
standing will even be a problem.
Also, the reflectors for the TH6 have separate elements for 10M and
a trapped element for 15/20. The last director is trapped for 10/20M
with separate directors for 10 and 15M.
If he really wants a smaller (shorter boom) antenna, he should
consider a beefed up version of the Force 12 C3. Maybe Tom
can make that for him.
In the Antarctic, they use WIRE antennas to survive the high winds.
VK0GC on Macquarie used 6 long wires, fed two at a time as
selectable VEE Beams.
de Tom N4KG
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