Topband: Shunt Feed Cage

[wb6rse1]

I shunt feed my 54 ft free standing 3 section crank-up tower for 160m and 80m, 
remote relay band switchable omega match. 2:1 SWR bandwidth is around 40+ kc on 
160 and about 20 kc on 80.

3/8” solid gamma rod, 15” from a tower leg attached at about the 22 ft level, 
the top of the bottom section of the tower. These parameters will not change 
nor will the fact that I have no radials since there is no place for them on my 
small city lot. There are two 8 ft ground rods at the tower base.

If I were to put a cage of 2, 3 or 4 wires around the gamma rod, each spaced 3 
inches or so from the rod, could I expect to see a significant improvement in 
bandwidth on 80m? Or I won’t know until I try it?

Tks - Steve WB6RSE
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Topband Reflector Archives - http://www.contesting.com/_topband

Re: Topband: Shunt Feed Cage

[Herbert Schoenbohm]

Steve, Space the cage wire should at least 24 inches under the belief 
that the fatter the structure appears at RF to be the  more bandwidth 
will be obtained. Also consider at a minimum a ground screen of rabbit 
fencing around the base of your tower to reduce your ground loses which 
are probably eating up 50% of your power as presently configured.



Herb, KV4FZ
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I shunt feed my 54 ft free standing 3 section crank-up tower for 160m and 80m, 
remote relay band switchable omega match. 2:1 SWR bandwidth is around 40+ kc on 
160 and about 20 kc on 80.

3/8” solid gamma rod, 15” from a tower leg attached at about the 22 ft level, 
the top of the bottom section of the tower. These parameters will not change 
nor will the fact that I have no radials since there is no place for them on my 
small city lot. There are two 8 ft ground rods at the tower base.

If I were to put a cage of 2, 3 or 4 wires around the gamma rod, each spaced 3 
inches or so from the rod, could I expect to see a significant improvement in 
bandwidth on 80m? Or I won’t know until I try it?

Tks - Steve WB6RSE
_
Topband Reflector Archives - http://www.contesting.com/_topband


_
Topband Reflector Archives - http://www.contesting.com/_topband