Thanks Ward!
-----Original Message-----
From: Ward Silver <hwardsil@gmail.com>
To: antennaware <antennaware@contesting.com>
Sent: Tue, Feb 5, 2019 10:56 AM
Subject: [Antennaware] BOG Signal Levels Near Transmitting Antennas
Yes, it could very well be. Antennas close (electrically) to transmitting
antenna systems are exposed to large fields and could pickup enough voltage
to damage a sensitive input. It's impossible to say how much without
analyzing or measuring the current levels in the radials and knowing how
far away the BOG is and a million other variables. The safest thing to do
is disconnect the BOG output from the receiver (or short it) when you are
transmitting.
On a related note - do not use anti-parallel diodes as an input clamp
because they will generate harmonics from the transmitted signal. This
isn't a problem unless you are trying to listen on another band while
you're transmitting, such as in a SO2R setup. Use a grain-of-wheat lamp or
one of the front-end protectors.
Other non-bypassed diodes connected to long, unshielded wires, like the
rectifiers in a HyGain rotator control box, will also act as harmonic
generators or mix multiple signals together. A 0.01 uF or similar
capacitor across the diodes will bypass the non-linear junctions. Hams
have a LOT of these diodes in their stations.
73, Ward N0AX
= = = = = = = =
Hey Ward, et al,
This is not related to the original topic but you mentioned BOG antennas
and I have a question.Is installing a BOG near the ground system of an
Inverted-L dangerous for a receiver? Separation between them would be about
1/8 wavelength, perhaps less, from the nearest radial.
In my situation, there would be radials and the BOG(s) in the same body of
water. I have no clue how much RF current and voltage would be in there.
Thanks, Joe, K8MP
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