Topband: Aluminum Lattice Tower

Art k6xt at arrl.net
Tue Jan 1 06:21:03 EST 2008


Bob
My setup is somewhat similar to your plans and very effective. It is a 
1/4 wave GP on 80 with radials at 15 ft instead of a ground radial 
vertical.

At about 55 ft up the GP I have a pair of more or less horizontal wires 
(vee style) to resonate the ant on 160. About 2/3 up the GP. The wires 
are fed via  traps which isolate them from the GP on 80. The traps are a 
couple toroids resonated with short hunks (about 1 ft) of open ended 
RG213 used as capacitors.

This setup is now 2 yrs old, has been very effective. I'm working on my 
best 160 year ever with around 15 new ones logged, and a new record for 
my section in the ARRL 160 test low power. As you can imagine, low power 
contesting on 160 is masochism but fun.

This is the ultimate in flexibility. Two long wavelength bands, no 
switches. EZNEC reports no effect of the horiz wires on 80 with the 
traps. Operationally it seems true, and there was no change in 80 feed 
R+jX as a result of adding the wires/traps measured with an Autek VA1. I 
could have used more horiz wires, but liked the EZNEC graphs best with two.

Best DX with your new ant.

73 Art

AD5VJ Bob wrote:
I now have an Aluminum Lattice Tower. It measures 12" across, has 8' 
sections and assembles to approx 67' tall.

I am wanting to make a vertical for 80 out of it and have about three 
wires attached to the top in order to make a top loaded
vertical for 160.

I have one section to put in the ground and then a solid very strong 
fiber glass rod (1 1/2" diameter) to mate the top section to
the section in the ground. Then run radials from the section in the 
ground and make a matching network.
[snip]


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