Telescopic Mast
Gray Frierson Haertig
>
> Hi Frank
>
> I will get flamed to death for this reply, I feel it in my bones!
>
> Having used push-poles for some 40 years, some home brew, some store
> bought, etc. I can forewarn you not to use fiber ropes of any
> formulation. Even the expensive UV and chlorine protected special
> nylon for use in swimming pools has gone bad in only a couple of years
> when used for guying.
>
>
> TTUL
> Gary
Had an AM client that had 162 foot towers guyed with mylar rope. It was
15 years before one of them blew down in a windstorm because nobody had
bothered to go out and inspect them. I suspect they were perfectly fine
guys for the first ten years.
Gray
P.S. All towers are now guyed with Phillystrand, which is bundled
linear strands of Kevlar in a black plastic sheath.
--
Telecommunications Engineering
Gray Frierson Haertig & Assoc.
820 North River Street, Suite 100
Portland, Oregon 97227
503-282-2989
503-282-3181 FAX
g...@haertig.com
Gray Frierson Haertig
>
> I wouldn't say all towers though! I know of a few local broadcast
> radio and TV stations that still use steel braided cable
>
>
> TTUL
> Gary
Isn't English wonderful. Of course I meant to say all of this client's
towers at this site are guyed with Phillystrand.
7 Strand galvanized EHS guy wire (and bridge strand in larger sizes) is
still the material used on the vast majority of towers.
Phillystrand is most often used for the upper ends of guy wires that are
in close proximity to FM or TV antennas. And sometimes used, as in the
case of my client, on AM arrays to minimize reradiation where the
standard method of breaking up metallic guys with egg insulators (johnny
balls) is deemed inadequate.
Gray
Gary V. Deutschmann, Sr.
>Had an AM client that had 162 foot towers guyed with mylar rope. It was
>15 years before one of them blew down in a windstorm because nobody had
>bothered to go out and inspect them. I suspect they were perfectly fine
>guys for the first ten years.
I don't doubt that one bit! I had a G5RV up for several years with
screendoor springs holding the tension tight. The coax fell off three
times, an insulator decomposed once, but the rope I used held strong.
It was flagpole rope purchased from American, which I now have going
to my balun on the pushup pole.
I have also used polypropylene UV, polyetheylene UV and other special
order ropes and they let the dipoles drop after only a few years.
I wanted to be more careful with my pushpole now that it's up so high
and has so much hanging from it, that I hope to never have to lower it
again. With that in mind, certain provisions, like pully's and twin
lines were used at the high stress points, so that if I see fatigue or
undue stretching of the wires, I can quickly replace them with new and
larger guage wire without lowering the antenna.
>P.S. All towers are now guyed with Phillystrand, which is bundled
>linear strands of Kevlar in a black plastic sheath.
Something I'm sure you can't pick up at the local hardware store! The
black sheath protects the line from the weather and damaging UV rays
as well.
I wouldn't say all towers though! I know of a few local broadcast
radio and TV stations that still use steel braided cable, and a couple
of those are even using the guy cables as directional dipoles for
their low frequency newsvan teams or something, coax runs from a
center insulator in these guys down to near the base and into the
little metal hut underneath.
But for us lowly hams, we have to stick with what we can buy, beg,
borrow or steal. And as you get up in years, guys are something you
don't want to mess with or worry about. Thus my warning against
(store bought) ropes, even those that appear to be great long lasting
ones, usually aren't.
If I were guying a tall tower, rather than a predominately eave
supported pushpole, I would probably consider cable or newer
technology fiber guys designed exclusively for that purpose. But
after forking out over a grand for new coax, and knowing the pushpole
held up at 46 feet for many years with no guys, the added security of
a few copper wire guys is more than sufficient to ease my mind, and
most guys are doubled as various antenna components.
I have also successfully used aluminum lead in cable scraps from the
electric company's lead ins to homes as oversized guys for the llittle
tower they were used for. But I was not afraid to climb that tower,
it wouldn't move if a house fell on it.
TTUL
Gary