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[TowerTalk] what is the experience with F12 dual-band ants and N radios?

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Subject: [TowerTalk] what is the experience with F12 dual-band ants and N radios?
From: (Guy Olinger, K2AV)
Date: Tue, 21 Dec 1999 17:16:58 -0500
Would not be 1500 watts into the blocking filter. That would mean that
no energy was radiated and all your transmitted power was being
channeled (somehow) into the other band's elements.

You would have to model it to see what the power actually was. I would
imagine something quite a bit less than 1500 but more than 100, as a
wild guess.

I might worry about toasting the bandpass filter.

If this is a 15/20 antenna, I would put a 20 meter open-ended
quarterwave stub & tee connector on the 15 meter line right at the
shack side of the balun. Vice versa on the 20 meter line.

With the bandpass at the shack, that might do it.

On a C31XR set for separate feeds, one would need two stubs on each
feedline, except a halfwave shorted stub for twenty would notch both
20 and 10 for the 15 meter feedline.

The idea in these would be to use the stubs to knock it down a bit,
and clean it up with the bandpass filters.

On Tue, 21 Dec 1999 09:55:07 -0800, you wrote:

>Both the Force 12 catalog and recent posts suggest that the multiple
>feedline multi-band antennas can be used simultaneously by different
>operating positions as long as appropriate filters are in place. Clarifying
>example: a 10/15 dual band antenna with two feedlines, being used
>simultaneously by different M/M ops, both running the legal limit.
>Have you tried this?  And did it toast any receivers? Or is overload a
>Seems kind of marginal to me.  1500W - 40db = .15W 
>150 mW directly into the antenna terminals seems a lot. I'd be interested in
>hearing how this as worked out for anyone who has tried it.
>73, Dave N6NZ

--.  .-..
73, Guy

Guy Olinger, K2AV
Apex, NC, USA

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