So far I only have one tower up so all my antennas are nailed to the one
mast. I am experimenting with an SO2R installation that I have hung
together.
My antennas are a C31XR at about 22 metres with three seperate feedlines, an
XM240 at about 27 metres and Inverted Vees for 160 and 80 metres at about 22
metres.
Obviously I have interaction between these antennas but overall things seem
to work.
My question concerns the C31XR. Does anyone have experience of using this
antenna with 3 feeders in an SO2R or M/S set-up?
In my installation I have adjusted the hairpin matches (I had to add one for
10 metres) and I now have SWR close to 1:1 at a selected point on each of
the 3 bands. Until, that is..........I put any sort of load across the open
feeder to the 20 metre yagi when I am transmitting on 15 metres. For
example, when I put a 10 metre stub across the 20m feed line the 15 metre
SWR jumps up to about 3:1. Not good.
So far I have cobbled a fix for this by putting a 15 metre parrallel tuned
circuit in the 20 metre feed line on the antenna side of the stub which is
on the output of the six pack just behind the Alpha. I made the tuned
circuit very high C and low L so it didn't screw me up too much on 20
metres. It sort of works but I wonder if anyone else has experience of this
and has a more elegant solution?
Any and all words of wisdom appreciated!
Thanks
Bob 5B4AGN
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