----- Original Message -----
From: "va3pl @ cuic.ca" <va3pl@cuic.ca>
To: <towertalk@contesting.com>
Sent: Wednesday, October 05, 2005 2:45 PM
Subject: [TowerTalk] Interaction between antennas
>I am installing my WARC Cushcraft A3WS + 30M kit 8 feet above my
>Mosley
> CL36.
> Should I turn it 90 deg in relation to Mosley or the seperation of 8
> feet is
> sufficient to heve both booms parallel which is prefered by me.
> Andy - VA3PL
It's almost impossible to predict such interactions. The most
sensitive indicator that interaction is occurring is degradation of
the f/b ratio on one or more bands. Measure the f/b of the CL36 before
you put up the a3. Then put the a3 up, booms aligned. Remeasure the
CL36 and measure the a3 vs. its specification. If f/b is degraded, try
rotating the boom 90 degrees. If f/b is still degraded, you will need
some different antennas.
It's easy to measure f/b:
1. Have a local ham friend 500 meters or more away transmit a carrier.
2. Turn the back of the beam toward your friend.
3. Note the s-meter reading.
4. Turn the beam toward your friend.
5. Crank in attenuators until the s-meter returns to the original
reading.
6. Reads the f/b ratio from the attenuator setting.
Dave Hachadorian, K6LL
Yuma, AZ
.
_______________________________________________
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather
Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions
and ask for Sherman, W2FLA.
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