HI Dick
That SWR run actually looks pretty good. I have exactly the same setup here
and my SWR is a little lower than yours--1.5:1 at resonance. You have to
remember that the impedance of that 160 meter inverted L isn't 50 ohms, it's
more like ~30 or so. The only way you could get a 1:1 would be to match the
antenna to the feedline. As long as the transmitter works, I'd not worry
too much about it. I just use the tuner in my rig if I move too far off
resonance.
SWR on a vertical can be misleading. I've seen some with perfect 1:1 SWR
with just a single ground rod, but that just means the antenna has lots of
loss. It was a great dummy load.
You could probably make a matching network of some kind, but you'd have to
switch it out on 80. 73 and GL
Tom W7WHY
I'm helping a friend who has an 80 meter 1/4 wave vertical. At the top, he
has a 160 meter trap then a wire extending horizontally for 160 meters. It
is therefore an inverted L on 160.
The SWR on 80 is good and can be adjusted nicely by changing the length of
the vertical component. 160 meters, however is somewhat of a problem.
The minimum SWR he can achieve on 160 is about 1.7:1. Of course the object
here is to lower the SWR on 160. Here are some readings we took with my
MFJ -269 antenna analyzer in case this helps anyone.
1.770, Rs 16, Xs 0, SWR 3:1
1.800, Rs 27, Xs 15, SWR 2:1
1.825, Rs 45, Xs 26, SWR 1.7:1
1.85, Rs 79, Xs 31, SWR 1.9:1
1.875, Rs 128, Xs 2, SWR 2.5:1
Can anyone point us in the right direction to find a solution?
Thanks,
Dick, W3OA
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