"Larry D" wrote in message
...
I want to construct a 5/8 wave ground plane for 24 MHz.
I am OK with the dimensions, but I can't get a grip on what
the impedance at the feedpoint will be. Even the ARRL
antenna book hasn't been much help.

Can anyone tell me the impedance I can expect to see,
also any tips on matching it? Thanks!

Larry DiGioia N8KU
N8KU at longwire.com

Larry, its been a while since I built one but I usually wind an 1/8 to
3/16wl of wire on my matching coil and feed this in series with as one would
a base loaded antenna then start triming the coil for lowest SWR. I have one
I built like that now on 10M SWR is about 1.5:1 . Cant say for sure but
think the feed point impedance is above 50 or about 75 ohms at resonance.
Have built these using the same technique for 6 and 2 . Seems like the
impedance on these can vary quite a bit depending on the materials you build
the antenna from. Thicker materials seems to give a lower impedance and a
better match to 50 ohms. Ive never really gone into what was going on with
the antenna that much and may be all wrong but right or wrong my way of
doing it seems to get the job done for me. Perhaps some of the gurus around
here would like to provide some more insight.