Gene,
This might be a case of acute C.R.S. of my earlier radio career...!
I worked on 2 different Trylons. These were both delivered as nestled,
"assembled" sections, not as put-together kits. But now that you questioned
it, I have to admit I don't recall whether these assembled towers used bolts
or rivets. I'm thinking they were bolted.
But whether rivets or bolts, whatever was holding the members together had
been sheared by the twisting torque. One tower which failed (folded over
under the rotor shelf near the top) had a twist set into it which you could
see when looking up the 64 feet that remained standing.
I recall looking up the side, thinking I could loosen all those bolts and
straighten the lower sections back into plumb. But I wasn't going to be the
one on the tower loosening all those bolts! That's something I might have
done in "K0RC, the early years"... :-)
73 de Bob - K0RC
----- Original Message -----
From: <ersmar@comcast.net>
To: "Robert Chudek" <k0rc@pclink.com>; <TowerTalk@contesting.com>
Sent: Tuesday, January 24, 2006 2:27 PM
Subject: Re: [TowerTalk] tower specs/not wind loads
> Bob:
>
> Which model Trylon tower is riveted? I own a T-500-64 (Trylon's Titan
> design) and I built the thing myself with SS bolts and associated HW. I
> didn't want readers to think that ALL Trylons were riveted. (Plus I'm
> curious.) Thanks.
>
> 73 de
> Gene Smar AD3F
>
>
> ----- Original Message -----
> From: "Robert Chudek" <k0rc@citlink.net>
> To: <TowerTalk@contesting.com>
> Sent: Tuesday, January 24, 2006 1:46 PM
> Subject: Re: [TowerTalk] tower specs/not wind loads
>
>
>> I will confirm what Gene is saying about the BX towers who's cross
>> members
> are riveted, not welded. In my youthful radio career, I put up 104 ft of
> HDBX tower. It was 4-way guyed at several levels. I installed a 6 foot
> torque bar at the top guy point to help reduce the twisting movement in
> the
> wind. Periodic inspection revealed rivets that had popped on this tower.
> As
> these were discovered I would install 1/4-20 bolts in their place. This
> tower survived 4 or 5 seasons with a 6-element 15m homebrew yagi on top.
> Oh,
> the boom was 2" OD irrigation tubing and was 40' long. (Did I mention I
> did
> this installation in my youthful radio career?)
>>
>> As an aside, our local radio community was fortunate to have a ham
> operator (WA0MGY - sk) who was our source for inexpensive undisturbed
> earth
> anchors. These were really slick... you auger an 8" hole at the proper
> angle
> about 8 feet deep, drop the anchor into the hole, use a special tool to
> expand the head of the anchor into undisturbed earth, and backfill the
> hole.
> Later when I removed the tower, I simply unscrewed the above ground head
> of
> the anchor and pulled the rod out. You would never know there had been an
> anchor in that location. I wanted to install elevated guy posts but was
> (fortunately) elmered away from this type of installation.
>>
>> Trylon towers are also riveted and I have found rivets that have popped
>> on
> these towers as well.
>>
>> I conclude these mechanical failures are a consequence of torsion forces
> created by the long booms on the antennas we use today.
>>
>> 73 de Bob - K0RC
>>
>>
>> * * * * * * * * * * * *
>> Message: 1
>> Date: Tue, 24 Jan 2006 14:27:12 +0000
>> From: ersmar@comcast.net
>> Subject: Re: [TowerTalk] tower specs/not wind loads
>> To:
>> Message-ID:
>>
>> Mike:
>>
>> You're correct - the BX-series of antennas has a torque limit on
> them. This is because they are assembled with rivets, not welds, between
> the cross pieces and between the cross pieces and the legs. The rule of
> thumb with these towers is that a ten-foot long boom would impart just
> about
> the maximum safe wind-induced torque on the tower. A longer boom might
> twist the thing apart.
>>
>> Caveat Amateur.
>>
>> 73 de
>> Gene Smar AD3F
>> _______________________________________________
>>
>>
>>
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>> http://lists.contesting.com/mailman/listinfo/towertalk
>
>
>
>
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