Gerard Jendraszkiewicz <jend@uchicago.edu> wrote:
Hello All,
Is there some way to see if a radial is still intact ? I have buried radials
and over time I think some have been broken. Any way to check ?
Thanks
Jerry, KE9I
= = =
Jerry,
I worked at 50 KW WTIC-AM in Hartford, CT (1963-80) before coming down to
Washington to work at VOA. We were experiencing problems that we thought to
be related to our ground system, so it was decided to check the radials,
using our trusty Potomac Instruments field intensity meter. The flip up
metal cover of this battery operated instrument is actually the shield for
the loop inside of it. As in all so called magnetic loop antennas, there is
a small air gap at the top of the shield. In order to check each radial of
with the 50 KW transmitter on the air, we had to desensitize the loop. We
simply shorted the gap at the top of the metal case with a small sheet metal
screw. This resulted in a much less sensitive FIM. On the unit's meter, we
were able to read the signal strength of the radial while walking with the
FIM right above it, a few inches above the ground.
The 120 old WTIC radials were made of 2" wide thick copper strap buried
below the surface. As we walked each good radial, the meter reading would
remain fairly constant if we stayed on track. It was very easy to follow
each radial from where it left the ground screen near the tower base to its
end. However, we found that a significant number of radials had completely
disappeared. It was apparent that over the years, the acidic Connecticut
soil on the top of WTIC's Avon Mountain QTH had completely disolved many of
the copper radials. An entire new burried ground radial system was
installed using insulated copper wire. This made for a much more stable
system, not affected by weather changing ground conductivity.
I would imagine that if you could construct a simple shielded loop, using a
diode detector and a voltmeter, you could walk the radials of your system
using a continuous source of key down low power 160M RF. Hopefully you
won't find that the earth has eaten your radial system like it did at WTIC.
73 de Rich - K1HTV
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