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[TowerTalk] Repeater / VHF Stack - Mast help needed

To: <towertalk@contesting.com>
Subject: [TowerTalk] Repeater / VHF Stack - Mast help needed
From: kd4rwn@bellsouth.net (kd4rwn@bellsouth.net)
Date: Wed, 3 Oct 2001 00:04:58 -0400
Hey All,

        My club Is planning an upgrade to one of our VHF towers that 
holds our 2M repeater antenna - This setup is on a large flat roof-
top.

Current Setup: 40ft Rohn 25' -Guyed at the 30ft. Top section is a 
sleeve top. A Hustler 2M repeater antenna is clamped onto the 
sleeve top itself - No mast.

Proposed setup: 30ft of Rohn 25' -Top section again sleeve top.
guyed right at the top. A mast and rotor are now being added. The 
antennas are as follows:

2M repeater Antenna 15' Ft Tall - 25 lbs - Approx 1.5 sq ft windload
440 Beam -Horizontal - 19L - 15' Boom
220 Beam Horizontal - 11L - 9' Boom
6M Beam - Horizontal - 3L - 6' Boom

Total Winload of the system is about 4.5 Ft or so. A few 
concerns/questions came up.

What Mast to use for this? .12 - .25 wall Steel and Molly come to 
mind. To accommodate the antennas - we're planning about 10ft of 
mast above the Sleeve top - with the repeater antenna on top. The 
problem there is now the mast/antenna combo is almost as tall as 
the tower itself. Weight would be another concern. Would the tower 
be too top heavy? We thought shrinking the tower from 40 to 30 ft 
would help matters overall. Safety factor of the system is important 
here. We're in Fl and get some good winds in the summer - Being 
on the roof 80' ft above the ground dosent help matters.

Any and all help in this would be appreciated....

73

Ulysses Rodriguez - KD4RWN
President - University Of Central Florida ARC (K4UCF)
Member: ARRL, FCG, WWYC # 77
kd4rwn@arrl.net





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