[TowerTalk] Unadilla Traps!

[pt2ho@contesting.com]

Dear friends from Towertalk,

I would like to get in touch with someone who has experienced the Unadilla traps. I am moving to another QTH in one year or so and I am trying to find out a solution for 40/80 meters. 

I have been operating on 40 and 80 meters with dipoles on the same mast at my current location with the 80 meters antenna on top and the 40 meters dipole 9 ft below. 

The pratical results and modelling (using EZNEC) show exactly the same, the 40 meters dipole is much more affected by its lower band cousin. If you remove the 40 meters dipole the 80 meters SWR keeps on low and tests on the air do not show much difference, however, the reverse situation (removing the 80 meters dipole) shows a low swr on 40 and better signals reports (at least from dx stations).

At the new qth the setup will be exactly the same. A Mast with
dipoles for 80/40... Do you believe that Unadilla traps will work ok?? Tuning is easy?? I havenīt had good experience with multiband dipoles, however, this solution looks to be something different, for me sounds like having monoband dipoles with a single coax cable.

If the Unadilla literature is right and my goal is 40/80 meters? I would have a dipole for 40 meters and would add the 40M ANT TRAPS (MODEL KW40), right? After that I would add an extra wire for the 80 meters antenna. It looks to be a very pratical solution. Do you agree??

Well, Perhaps someone has experienced this setup...

Please reply directly to me and I will post a summary back to the
reflector if there is any interest on this subject.

Thanks for the bandwidth and 73,

Carlos PT2HO (also PY1CAS)
pt2ho@contesting.com

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