I have a Tri-Ex Sky Needle, a TM-358 (58'). it's a great tower. I would
love to find a 70-footer (TM-370 or TM-370HD, which was the same size as
the TM-390 (90') minus the top section, and quite rare as it was as
expensive as the taller tower).
The Tri-Ex Sky Needles were last manufactured in the late 80's, early
90's. They range from the TM-240 (40', direct lift, no pull-down
feature) to the TM-5100R (100', where the top 32' rotates using a prop
pitch motor). Wind load ratings were quite good (rated at 78mph, the
TM240 was @ 9.5 sq. ft., TM358 @ 7.2 sq. ft., and the TM-370, TM-390 and
TM-5100R @ 20.1 sq. ft.). The pipe sizes ranged from a top section of
2-7/8" OD x .203 pipe to the largest at 10-3/4" OD x .365" pipe. In the
late 80's, the TM358C sold list) for around $6-7000, with the TM-5100R
costing, I believe, around $20,000, which is probably why you don't see
too many (I bought mine reconditioned)
Early models used a cylindrical rod for a section guide, but it was
welded in spots along the rod and could be snapped loose with the torque
placed on it from longer boom yagi's. Tri-Ex changed to a C-shaped bar,
which is better to resist the torque from longer boom lengths. Sky
Needles with the C-bar have the "C" designation after the model number,
and are more desirable (although you can weld the rod along its length
and make it a lot stronger).
Most towers came with a high ratio worm gear winch (varied by model from
40:1 to 50:1) to raise and lower the tower coupled to a 240v motor.
Positive pull-down was used on the cable. The rotor is mounted inside an
offset cage to a jackshaft and gear, which runs via a chain to another
gear in which the antenna mast is clamped.
Accessories included a ladder, work platform, and a raising fixture (big
gin pole). I have the raising fixture, and it's great for lowering the
tower to the ground to work on the antennas.
They are visually nice to look at, and are very strong towers. I wish
these were still on the market, they are truly the "Cadillac" of
crank-up towers.
73,
Lou, KB0CJ
-----Original Message-----
From: Alan AB2OS [mailto:ab2os@att.net]
Sent: Saturday, July 17, 2004 1:08 PM
To: towertalk reflector
Cc: Richard (Rick) Karlquist (N6RK)
Subject: Re: [TowerTalk] Limitation on tower width. Was: Revocation
ofBuildingPermit?
Can't find anything about Sky Needles except that they were made by
Tri-Ex, which is no more. I understand that Tashjian took over Tri-Ex
but was getting rotten reviews, and I can't find "Sky Needle" on his Web
site either.
Alan AB2OS
On 07/17/04 01:18 pm Richard (Rick) Karlquist (N6RK) put fingers to
keyboard and launched the following message into cyberspace:
> Cupertino has a 12 inch width limitation, which
> is just enough for Rohn 25. Basically, that limits
> you to guyed towers or self supporting pipe towers.
> A 55 foot Sky Needle would be perfectly legal.
> In many cases, a Sky Needle is an excellent solution
> for city lots, but it seems to be an overlooked option, judging by the
> amount of discussion about zoning issues.
_______________________________________________
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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