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[TowerTalk] shunt feeding tower on 160

Subject: [TowerTalk] shunt feeding tower on 160
Date: Sun, 11 Nov 2012 18:59:41 +0000 (UTC)
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Good afternoon. I have 118 feet of Rohn 45G which, at the moment, has no 
antennas on it. It is guyed in 3 places using Philly and sits on 1.5 cubic feet 
of concrete with a pier pin at the base. The tower is grounded (three 5/8" 8 
foot rods per leg, spaced at 20, 40 and 60 feet from the tower in a line and 
all connected with #2 copper) and I have layed out 33 130' radials (#14 
stranded copper, insulated) as the ground screen. If you disconnect the ground 
rods (not the radials) the tower has a resistance of 37 ohms at 1.830 and an 
SWR of 2 (according to my MFJ 259B). I would prefer, however, for lightning 
protection, to leave the ground connections in place and use a gamma wire and 
capac itor to match the tower for use on 160. I have tried, using a wire 
running from near the top of the tower, and with spacing from the tower varying 
from about 28 down to 14 or so inches, to find the 50 ohm tap point for the 
tower. This seems to occur, interestingly enough, at about 3 feet off th
 e ground. Since this seems a bit odd I consulted local antenna guru, N4KG, and 
he too thinks the tap point should be significantly higher, at least 30-40 feet 
if not more. I don't have much experience with this to draw on so I would like 
to ask the group for ideas or input. This also seems to vary quite a bit from 
articles I have read on the subject in the ARRL antenna book and in Low Band 
DXing, although virtually all of those articles concern towers with some sort 
of top loading provided by yagis. Thank you in advance for your advice, Steve, 

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