Re: LF: Re: Noise cancelling by using optic transmission of RX signals

[Andy Talbot <andy.g4jnt@googlemail.com>]

In which case, mounting it on top of a 20m high steel framed building
is like having a 20m whip????

Or does the size of the plane under the active element matter.   Our
works one has an antenna platform of a few metres square of metal grid
which itself is a few metres above the roof of the actual building
(erected to keep antennas above air conditioning plant and safety
walls)

Andy
www.g4jnt.com

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2009/12/19  <jrusgrove@comcast.net>:
>> I think the role of the ground with active whips is often neglected - the
>> output of the whip preamp is the voltage differential between the whip
>> element and the circuit ground, so the ground connection is just as much
>> part of the antenna as the whip element itself is.
>
> That's an important point that is often overlooked or ignored. A mini whip
> mounted up at 5 meters is a 5 meter antenna. You can easily prove this by
> mounting it at ground zero on top of a ground screen. Been there, done that.
>
> Jay W1VD  WD2XNS  WE2XGR
>
>