I had a couple of Hy-Gain monobanders and they also shed element tips.
The 7/16 tips have a very thin wall, around .030 if I remember correctly
and mate to a much larger swedged section creating a break point. There
are much stronger element taper schedules in the ARRL antenna book.
John KK9A
To: towertalk@contesting.com
Subject: Re: [TowerTalk] [Bulk] Re: [Bulk] Re: Rotator Choice for Larger
Yagi
From: Bob K6UJ <k6uj@pacbell.net>
Date: Wed, 4 May 2016 11:44:33 -0700
List-post: <towertalk@contesting.com">mailto:towertalk@contesting.com>
I remember the rope dampers Grant. I had the same issue and resolved it
with the poly rope. I went out to my back yard and found element sections
stuck in the ground like they were
shot like an arrow.
Bob
K6UJ
On 5/4/16 11:30 AM, Grant Saviers wrote:
Which reminds me of the rope dampers in my prior TH7DX. Apparently, the
elements w/o traps were falling off due to coupling of element mechanical
resonances. HyGain/Telex came up with a clever fix by putting a 2 ft
length of polypro rope into the tips of those elements to dampen the
vibrations. A nasty property of aluminum is that it has no fatigue limit
like steel. If a certain stress level is not exceeded, steel won't fail in
fatigue. There is no such threshold in aluminum. A small stress over many
cycles and aluminum will fatigue fracture.
Grant KZ1W
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|