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[TowerTalk] More antenna work

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Subject: [TowerTalk] More antenna work
From: "Roger (K8RI)" <>
Date: Sun, 21 Oct 2007 23:44:23 -0400
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I knew finding one of the boom trusses for my 7L 6-meter yagi on
the concrete apron in front of the shop this afternoon was not a good sign.
Then I noticed the 50, 144 and 440 antennas were windmilling and the
tri-bander was not. That the tri-bander wasn't was a good sign as it's
temporarily setting on the 45G top plate. However the only way the others
could windmill would be if the through bolts holding the mast togeter
have sheared.(or fallen out) So the only thing stopping the rotation are the
LMR 400 Ultraflex rotator loops.

We've had some very strong winds over the last week with one day of severe
weather where we were under a tornado watch for nearly 12 hours.

At any rate it looks like the 6-meter yagi is going to have to come down
for maintenance as are the 144 and 440 arrays.
I'm getting started on the 50 or 60 foot,  rotating, fold over pole (I asked 
about on TT about a month or so back) to go on the back (West) end of the 
shop. I decided it wouldn't take all that much more to make the thing a 
rotating pole.
 So the 6-meter yagi may go there as it really doesn't need to be at 115 
feet. OTOH I do want the 144/440 arrays as high as I can get them. Actually 
50 feet should be good for the tribander as well. Then I could put a 3 or 4 
L 40 up on top of the 45G.

I said 50 or 60 feet and that depends on the price of steel. Going from 50 
to 60 feet doubles the cost (or
a bit more) of the pole and adds almost 30% more weight to the pole and to
the base/raising fixture. It also requires more concrete.

A 40 meter yagi might be just a bit much as I'm just getting back to 
climbing. I did make it "up there" last week which aint bad considering I 
needed help to stand April 4th.  I'm still a ways from the old "stay up 
there all afternoon" though. <:-))

This leaves me back to using the AV-640 on 6 until I get the rotating pole 
finished, installed and running. Hopefully I can get the base in before the 
ground freezes and the pole up before the snow gets too deep to haul nearly
400# of steel through the yard to the back of the shop.  I still haven't 
figured out how to get the congcrete back there.

Roger (K8RI) 


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