Reply To: Counterpoise and RF Grounding a mobile antenna

Nashua Area Radio Society Topics In All Forums Elmering Forum Counterpoise and RF Grounding a mobile antenna Reply To: Counterpoise and RF Grounding a mobile antenna


Jay Cohen

Fred – I actually came across that article in my research!  The ‘relative’ question is how elevated is elevated?  Meaning, if I hang three 1/4 wave counterpoises  angled down from the antenna who’s as high up (6 or 7 feet for the bottom antenna connection) as I can get it on the stand I have and terminate them about a foot from the ground, which makes the downward angle around 30 degrees of slope gives me between 40 and 50 ohms of impedance which ‘should’ give me a decent swr.

But, and there’s always a but, if the impedance numbers are only true if the antenna is at least 1/4 wave above the earth, I still might be better off with the 4-8 ground radials at 33.5′.

The other school of thought though is do I extend the ‘whip’ on top of this 1/4 wave antenna by about 33.5 feet and call it a day…  A 1/2 wave antenna technically shouldn’t need radials, and with the automated screwdriver adjustment of the atas120a, that should be easy to tune at 40M, 20M and potentially 10M as well.  I do happen to have a pretty tall oak tree on that side of the house…  Hmmmm.  2M and 70cm work perfectly already, so no big deal there.

Does the club ‘rent’ SWR meters for those, who like me, are still in the ‘tinkering’ process?




Jay, KU1DU

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