[TowerTalk] Guy wire resonance

[Mike Gilmer - N2MG]

On Tue, 05 June 2001, "J. Kincade" wrote:

> One Talkian pointed out that Phillystran isn't that 
> much more expensive than steel, and of course does 
> away with all the guy wire resonance problems. 

A topic currently near to my heart (and wallet).

I'd like to see the numbers for your 75 foot R45 tower.

For a tower of ~120 feet (for which I'm in the throes 
of constructing) the numbers show that Philly is about 
2X EHS. 

Roughly, for 120ft tower, 80% guy spacing, four guys 
per side equates to 1650' guy wire.  With 4 insulators per guy (48 total) and 10 grips/guy (8 for the insulators, 2 for the ends) and ignoring thimbles/sleeves (and ASSEMBLY time!) I get:

************EHS

1/4" EHS    $0.189/ft
502 insul   $5.50
Big grip    $6.00

(1650ft * $0.189) + (48 * $5.50) + (120 * $6.00)
 = $1296

************Phillystran

6700# Philly   $1.29/ft
grip           $12.00

(1650ft * $1.29) + (24 * $12.00) 
 = $2416

**************

This uses TexasTowers pricing (no not the cheapest for 
steel, but the only game for Philly).

EHS costs can go lower as you can shop around: there are various commercial sources and, albeit limited, hamfest-type availability for EHS stuff.  If you're in a hurry, then, well, this is somewhat moot.

The performance issues have been addressed here before, and IMO, the classic tradeoff of 
price/performance looks good for Philly. But for me 
(and I'm trying to build two such towers), I'll take 
the "sweat equity". :)


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