[TowerTalk] phillystran vs lightning

[Pete Smith]

At 08:05 AM 6/17/00 -0600, n4kg@juno.com wrote:
>
>Have you considered the fiberglass guy material that W3LPL
>and others use for their big towers?  I would have to check
>my archives to find the supplier's name / address.

The stuff is manufactured by Polygon, and is called pultruded rod.

>
>To prevent interactions with stacked antennas, you need to
>break up the guys every 3/8 WL at the highest frequency
>(every 12 ft for 10M) out to about 1WL, above and below
>the sidemounted beams.  The first insulator needs to
>be placed as close as possible to the tower because
>of continuity through the guy through the tower and 
>back to the other guys.
>
>Phillystran and fiberglass begin to look real attractive
>for tall towers!

Unfortunately, as Heinlein says, "TANSTAAFL."  That is, there ain't no such
thing as a free lunch.

The Polygon material is less expensive than Phillystran and PLP makes guy
grips for it, but they sell only in large lots and shipping isn't cheap
because the stuff is pretty stiff (makes for large coils).  That means you
pretty much need to put together a group buy to make it work.  Also, it
can't be stored rolled up for any length of time.  

On the other hand, as someone demonstrated on this reflector (I've seen it
in the archive), Philly works out to be much more expensive than equivalent
lengths of EHS, even when broken up with johnny balls and big grips.

Ah well...

73, Pete Smith N4ZR
n4zr@contesting.com 



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