[TowerTalk] Making an 80 meter vertical from Rohn 25

[Art]

>    5. Re: Making an 80 meter vertical from Rohn 25
>   
This is exactly my 80M 1/4 wave vertical. Mine is fed at 15 ft AGL as a 
ground plane. The 15 ft attachment point is insulated from the R25. I 
use an aluminum tube out the top of the R25 to resonate the ant where I 
like it (the CW end of the band). It works extremely well and is easy to 
adjust with the Al pipe. Mine has 18 elevated radials. An excellent 
solution.

If you're feeling ambitious you can use it on 160 as a 1/8 wave. The 
feed Z is high on 160. I resolved this issue (first in EZNEC) by 
attaching a pair of drooping wires at the top of the R25 where the Al 
pipe starts. In my situation these wires are about 25 ft long. The two 
wires reduced the feed Z to a point the active antenna coupler was 
happy. 160 is similarly extremely effective. I'm working plenty of DX on 
both bands.

According to EZNEC the drooping wires had almost no effect on the 
radiation pattern. The two wires are isolated on 80M by homebrew traps 
made from toroids resonated by short (about 1 foot) lengths of RG213.

I tune the antenna on 80 as it should be and take what I get on 160.

73 Art K6XT
>
>   
>> I'm wanting to put up a full sized 80 meter vertical made from Rohn 25 in  
>> my pasture. 
>> Marty Haley AB5GU  
>>
>>