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Old February 10th 07, 06:37 PM posted to rec.radio.amateur.antenna
Jerry Martes Jerry Martes is offline
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First recorded activity by RadioBanter: Jul 2006
Posts: 173
Default Antenna Pattern Distortion due to 2 antenna placed in near vicinity


"Rohit" wrote in message
oups.com...
Because i need 180 deg coverage i have to use both antennas together.
The 3dB beamwidth of 90deg of both antennas give me 180deg coverage.
And i expect the gain to be 3dB down at 90deg but instead i am getting
gain less by 10 to 15 dB. Is there any way i can get less ripple at
the overlap?



Hi Rohit

I think this "pattern merging" will become clear to you when you consider
the fact that the signals from each element has equal amplitude at Crossover
(90 degrees). Therefore the signal at that direction will add to twice the
value of either, ir subtract to zero, depending on their phase. That is a
heck of a big difference from In Phase to Out of Phase.

I'd suggest that you include more info about your ultimate goal. There
are some very well informed guys reading this news group who might be
willing to help you.

Jerry