In a message dated 9/18/2005 2:31:34 PM Pacific Daylight Time,
towertalk-request@contesting.com writes:
> In 1999 I put up a Glen Martin M-1870A 70 ft tower package that came with
Kevlar guys. The tower is guyed at 35ft and at the very top of the tower at
70ft.
> Mounted about 2.5 ft above the top of the tower, and thus about 2.5 ft
above
the connection of the top guys, is a F12 C31XR.
> Last winter, one of the top guys broke where ice accumulates at the bottom
where the guy loops back on itself. I plan to replace all guys. I notice
that Glen Martin is now supplying EHS with their tower packages instead of
Kevlar.
> I would consider replacing with EHS instead of synthetic, but worry about
SWR and pattern changes. I don't want a combination solution with part
synthetic and part EHS.
OF COURSE you want part synthetic and part EHS. The synthetic guy under
tension is easily severed with a razor knife...bye, bye tower. It also burns
easily. You want the last 15' or so to be EHS to the anchor so that neither of
those situations are possible.
> I've googled and checked archives - Anyone have specific experience how
changing to EHS might affect SWR at this height and with this antenna?
It's a matter of speculation with no overwhelming reason that I've seen
to do it one way or another. I've used Phillystran and recommend it for any
populated tower; that is, a tower with several antennas on it, particlarly
wires
or sidemounted yagis. And yes, you may introduce some destructive interaction
with EHS but I don't know of anyway to predict it until the antennas are
installed. If in doubt - go with the synthetic guys again, you know how they'll
work.
> We have nasty winters here and it gets pretty windy in the spring. I have
nothing but good to say about the tower and the C31XR! (The guy break could
probably have been avoided if I had treated the terminations differently! I
just used cable clamps and taped the folded-over end of the cable in
tapering fashion from above downwards.)
Okay. Does any tower or wire rope manufacturer recommend this technique?
No, they don't. Your mistake was to violate the LXC Prime Directive to "DO
what the manufacturer says". The converse is also true.
Don't feel like the Lone Ranger. A local guy did the same thing 10 years
ago or so - the guy broke and the tower came down.
Cheers,
Steve K7LXC
TOWER TECH -
Professional tower services for commercial and amateur
Cell: 206-8904-188
_______________________________________________
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather
Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions
and ask for Sherman, W2FLA.
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