Severe overload problems in the K9AY array from the transmitter will also
cause overheating/burning up the 2 watt terminating resistors in the relay
box at the antenna. I've seen arrays that are only a few feet from the
transmit wires.
Jim - KR9U
-----Original Message-----
From: Topband [mailto:topband-bounces@contesting.com] On Behalf Of K4SAV
Sent: Friday, October 11, 2019 10:25 AM
To: topband@contesting.com
Subject: Re: Topband: Protecting an Array Solutions K9AY Loop from
Transmitted RF
It's likely you won't need any protection from the transmitter (lightning
protection may be another story). To verify this you can either use an
oscilloscope on the output of the K9AY or just build a diode / cap detector
and use a voltmeter.. Then ramp up the power to see how much voltage is
picked up. I was surprised when I did this.
None of my receiving antennas picked up enough signal to worry about.
Check the pickup on all frequencies you operate. The gain of a K9AY is much
higher on higher frequencies even though the pattern is very poor
on higher frequencies. It's likely that on higher frequencies there
will be more voltage across the K9AY terminating resistor than at the output
of the antenna.
Simulation shows no problem at 60 ft separation on any frequency but check
it to be sure.
If you decide to use a limiter, make sure there are no AM stations close
enough to forward bias the limiter (even by the smallest amount). If that
happens all kinds of intermod products will show up on receive.
Jerry, K4SAV
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