Hi Mike...
No, unfortunately I don't know much about the Telrex designs. When they
were manufacturing antennas I was lucky to be able to afford 150 feet of
copper wire, some TV ribbon cable, and an 807 CW transmitter! (Knight
Kit T-50)
But I do know that HyGain put rope in some of their antennas for the
dampening effect. I think my TH-5DX had ropes in some of the elements
(or maybe it was the Cushcraft ?).
73 de Bob - K0RC in MN
------------------------------------------------------------------------
On 9/7/2011 9:30 PM, Mike & Becca Krzystyniak wrote:
> Hi Bob,
>
> As you may know, the original Telrex designs used a double wall tip to
> dampen the low rate oscillations caused by the wind or other (and many used
> the corona tear drop too). The double walls on the element tips of my
> 20M436 were in the neighborhood of 4' - 6'. Put in backwards the element
> tips broke off in just a few months. Double wall toward the boom and none
> failed, ever. And it never rattled in the wind either. Element wig-wag
> became my next foe...
>
> 73's Mike K9MK
>
>
>
> -----Original Message-----
> From: towertalk-bounces@contesting.com
> [mailto:towertalk-bounces@contesting.com] On Behalf Of Robert Chudek - K0RC
> Sent: Wednesday, September 07, 2011 6:16 PM
> To: TowerTalk@contesting.com
> Subject: Re: [TowerTalk] Aluminum tubing slip joints seized - my final
> answer
>
> The issue was a little more "complex" than I first thought.
>
> I discovered there wasn't a simple 4" to 6" of overlap, but about 48"
> instead. It's apparent this antenna was not assembled to manufactures
> specifications. The extra tubing did not add to the mechanical strength.
> It only added unnecessary weight. The excess tubing was at the tip end
> of the tube, not the tower end.
>
> What did work to some extent was inserting another (long) tube from the
> opposite direction and driving the inside tube toward the tip. This was
> only partially successful and I had to resort to the hacksaw. Actually,
> I used a tubing cutter for a clean cut. Then I drove the remaining
> inside piece back toward the tower end. I had to use this method on both
> halves.
>
> Pulling a few pieces from my aluminum pile I was able to reassemble the
> antenna. At the same time I added stiffening to the junctions by adding
> internal sleeves where needed.
>
> The remaining task is to model this (again) and see how to make a 62.5
> foot element resonate at 7.1 MHz. I'm thinking capacity hats somewhere
> out near the ends, like the Cushcraft 2 element 40m yagi.
>
> 73 de Bob - K0RC in MN
> ------------------------------------------------------------------------
>
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