[NLRS] Dual Band Radio to Seperate Yagi's

[KB0NLY]

Thanks for confirming my suspicions.  Its not a problem to run a diplexer, I 
just wanted to hear it from others.  I don't know how the Cushcraft dual 
band beam works either, but both sides of the harness that go to the driven 
elements from the tee are the same length.  Then again I don't know how well 
that antenna works in the real world!

I will just put a diplexer in a waterproof box up on the tower.

73,

Scott


----- Original Message ----- 
From: <jcplatt1 at mmm.com>
To: <nlrs at mailman.qth.net>
Sent: Thursday, September 11, 2008 11:21 AM
Subject: Re: [NLRS] Dual Band Radio to Seperate Yagi's


>
>
> Hi Scott.  If I understand your question correctly, your radio has one RF
> port where both 2m and 432 come from.   Your current vertical is probably 
> a
> dual band vertical, so this works just fine.  Now you wish to also be able
> to run separate 2m and 432 beams.
>
> You cannot simply "T" the 2m and 432 antennas together and drive them from
> the one RF port on your radio - this may work for just 2m as the 432
> antenna will not be "seen" as too much of a load on 144 MHz, but this will
> definitely not work on 432 as the 144 antenna is 3/4 wavelength on 432 and
> will load nearly as good as the 432 antenna on 432 .... 432 will be
> "screwy".   This is the same physics as to why a 40m dipole also works on
> 15m.   Yes, you will need a diplexer somewhere along the way to isolate 
> the
> two single band antennas from each other.   The diplexer could be up close
> to the two antennas so that you only need one long run of coax from the
> radio to the two beams.
>
> I'm not sure how the CC dual band antenna gets away with this other than
> you can do it but the pattern will be screwy on 432 .... 2m will probably
> work OK.
>
> 73, Jon
> W0ZQ
>
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