OK, here is what I want to do:
I have a 33' (10m) vertical with the base about 10' (3.3m) above ground.
It has four 8' (2.4m) radials which are connected to the feedpoint
through a coil which resonates the system on 7 MHz. It works as well or
better than any vertical that I've used on 40m -- low SWR and good
results. It's fed through a relatively short (20', 6m) length of RG-213.
I would like to use it on 80m and 30m as well. My first try was to
simply use the KAT100 to tune it. It tunes fine on both bands (1:1 at
the rig), but results are fair-to-poor on 30 and poor-to-worthless on 80.
On 30m, the coax losses are reasonable (the SWR on the coax is about 8
to 1, but it's very short). I suspect the problem is that the radial
ground system is very poor on this band (on the other hand, the long
vertical radiator should provide a slight amount of gain). So I may try
paralleling a set of radials tuned for 30m. They will also be short,
but resonated with a coil or stub. Does this sound like a good
analysis/solution?
On 80m, it's more complicated. The ground system is terrible, the
radiation resistance of the vertical very low, and the SWR and losses on
the coax very high. No wonder it's a dummy load! I guess the way to
deal with it is to add more tuned radials in parallel and a switchable
base network, but I would like to avoid any more control wires that have
to go through my lightning suppression panel (I can't pass DC through
the coax, either). Does anyone have any suggestions?
--
73,
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco
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