[TowerTalk] Unique Short Radial Challenge - N5OT Question
Mark Beckwith
n5ot at n5ot.com
Sun Oct 21 20:37:07 EDT 2007
> Radials under the K9AY loop???
Careful now, you're talking to someone who doesn't get a lot of RF
hocus-pocus. All I know is K9AY says "a ground rod is usually sufficient"
but I'm pretty sure he doesn't elaborate too much on what to do when a
ground rod is not sufficient.
I don't know if my ground rod is insufficient, but I do know that with a 470
ohm fixed resistor (not the 390 ohm resistor Gary recommends as optimum for
160), I get fair results in the F/B department but might like to try for
better results. I'm "measuring" 10db or so F/B but not convinced of my
measurements either - it could actually be better than that. That's how
much the S meter changes when I reverse the antenna, pointed at a signal in
line with the loop (local BC station on 1400 kHz).
Also, I suspect my ground rod may not be sufficient because I have bedrock
about 14 inches down so that's all the ground rod I have under this antenna
at the moment and if "improving the ground" were as easy as, say, laying 8
radials on the ground out to the circumference of the loop (about 17 feet) I
would try that and see if it helped, since it's so easy before attempting
the more obvious approach of fine-tuning the termination resistance.
Mark, N5OT
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