Topband: Dual band shunt-feeding tower on 160/80

[Pete Smith N4ZR]

I have a 97-foot Rohn 25 tower with 2 X C-3Es and an EF-240S on top.  I 
tried initially to find a 50-ohm point on the tower, without success, so 
I then went to an Omega match, using a pair of 300 pF transmitting 
variable capacitors bought from Henry Radio. It proved very easy to 
tune, with reasonable bandwidth, and works fairly well despite low power 
an an inadequate radial system.

You might be able to switch in another match for 80M, but instead I use 
a 4X lazy vee array - See K3LR's article in QST August 1994 - hung off 
the same tower.  It has definite though broad directivity and is just a 
few Db down into Europe, compared to an 80M 4-square.  If anything, I 
believe the tower helps the directivity.

73, Pete N4ZR
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On 8/25/2013 11:43 PM, Jeff Blaine wrote:
> A buddy of mine has a 100’ 25G tower and wants to run it on both 160/80.  I’m thinking a par of shunts will work for that?
>
> If you have done this, I would be interested in your comments on the general implementation.
>
> Thanks!
>
> 73/jeff/ac0c
> www.ac0c.com
> alpha-charlie-zero-charlie
>
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