The FCC has a set of curves covering 530 to 1700 kHz that simplify the
determination of effective ground conductivity near a transmitting site.
This assumes you have an operating antenna, RF source, field intensity
meter and good maps and/or GPS receiver.
This indirect method does not work so well at VLF frequencies such as 30
kHz, since the losses in the antenna cloud the losses in the earth, even
with a very large antenna and ground system.
Is there a reliable method for determning VLF ground conductivity? The
devices made for 60 Hz AC power systems don't work above about 200 Hz. I
have investigated a number of these "megger" type boxes, and can't get a
custom version made for 20 or 30 kHz.
Grant Bingeman
-- The NEC-List mailing list <nec-list_at_gweep.ca> http://www.gweep.ca/mailman/listinfo.cgi/nec-listReceived on Sat Sep 22 2001 - 01:24:46 EDT
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