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Old January 22nd 05, 11:53 PM
W9DMK
 
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On 21 Jan 2005 20:20:18 -0800, "kernelkole"
wrote:

Of the solutions presented in the ARRL Antenna Book for 2nd storey
grounding...ha, ha! There are no solutions!

But that doesn't help me.

I live in an apartment - a set of rooms in a 100+ year old building, so
you'd THINK they'd have copper/metal plumbing; but, no. It's been
pvc'd. So no cold water pipe.

The ARRL cautions, and I concur, against dropping a long bit o' wire
from the window to the ground - many issues, including having the
ground wire function as a resonator, or, RF burns from touching th
radio. Don't want those.

There's the MFJ "artificial" ground, but I don't see how that would
work with the ATAS 100 I have - like having an antenna tuner for an
antenna tuner.


The only aspect of this that has not yet been presented adequately is
the artificial ground. I neither subscribe to nor recommend this, but
you should at least be aware of how it is intended to work.

The "artificial ground" has one end connected to your shack ground (in
your case the chassis of the transmitter or tuner will do nicely.

The other terminal of the "artificial ground" connects to a length of
wire that is just sufficient to connect to an earth rod driven into
the soil beneath the shack. The "artificial tuner" internals consist
of a series resonant circuit - a capacitor and a multiple tapped
inductor and an RF current detector. The "artificial ground" is tuned
for a maximum of RF current when your rig is transmitting. The
artificial ground with its length of wire from the rig chassis to the
earth rod makes up a series resonant circuit that is electrically an
integer multiple of a half wave. That presents the lowest possible RF
impedance between the chassis and the earth rod (as indicated by the
maximum of RF current in the artificial ground).

The effect of this will be to make the chassis of the rig "cool". It
will have no effect on the antenna tuner, but it will reduce the flow
of RF current through other devices in the shack via power cords.


Bob, W9DMK, Dahlgren, VA
Replace "nobody" with my callsign for e-mail
http://www.qsl.net/w9dmk
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