[TowerTalk] FW: Tune 160/80 Vertical

[Tom Osborne]

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