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1/4 Wave GP Help
- Thread starter Riverman
- Start date
If it has only 1 radial it behaves more like a dipole. For a dipole close to the ground there will be potentially significant ground and nearby objects interaction. Also, while a 1/4 wave GP may be tunable with a 102" long vertical, that is, in my experience too short for a dipole on 11m.
My advice is to add at least two or three more radials and lower the ends equally to get the impedance right and the antenna should tune.
Someone else may have a different take on this.
My advice is to add at least two or three more radials and lower the ends equally to get the impedance right and the antenna should tune.
Someone else may have a different take on this.
I’ve had good success with antennas using only one radial, but in hindsight, my past ones were all much higher.
Good catch. And thanks, Homer.
Hold on. Got a fly in the ointment.
I kept thinking even with it being low and perhaps a few inches off on length, the SWR shouldn’t be that high (5.2). So I removed the 102” steel whip and the SWR didn’t change at all. I’m thinking I have a bad stud mount. And that the antenna I’m measuring is the coax, metal tripod and wire radial.
Any thoughts?
I kept thinking even with it being low and perhaps a few inches off on length, the SWR shouldn’t be that high (5.2). So I removed the 102” steel whip and the SWR didn’t change at all.
I’m thinking I have a bad stud mount. And that the antenna I’m measuring is the coax, metal tripod and wire radial. Any thoughts?
Check the setup for continuity with an ohms meter. Homer is right if it checks OK.
Try lowering the radial angle and secure it with a wood or plastic peg about an 1" above ground. You could raise the antenna a bit higher if you need more radial angle down to see a better match.
Not a good idea if pets or humans can get into the wire however.
Try lowering the radial angle and secure it with a wood or plastic peg about an 1" above ground. You could raise the antenna a bit higher if you need more radial angle down to see a better match.
Not a good idea if pets or humans can get into the wire however.
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Checked continuity yesterday and is fine. Reinstalled the whip. Left radial as is (16.5’) 3’ above ground. Too tall for dog, no kids. Drove to Love’s truck stop and bought a new stud mount. Returned, installed it and SWR dropped from 5.2 to 3.2! Shortened the radial to 8.5’ and SWR dropped to 1.16! Happy days are hear again!
Well, now, you never told us you had a 20m 1/4 wave GP laying on its side with a too short single radial pointing up...
In that case we'd have told you to cut that 20m horizontal (somewhat) radiator to ~8.5' and resonate the vertical radial as your 11m dipole/GP.
In that case we'd have told you to cut that 20m horizontal (somewhat) radiator to ~8.5' and resonate the vertical radial as your 11m dipole/GP.
Well, now, you never told us you had a 20m 1/4 wave GP laying on its side with a too short single radial pointing up...
In that case we'd have told you to cut that 20m horizontal (somewhat) radiator to ~8.5' and resonate the vertical radial as your 11m dipole/GP.
A small detail overlooked.
Sorry for the confusion. 1 steel whip and 1 wire. It’s this antenna without the Chameleon matching unit and with the radial shortened to 102”.
Hey man, you're reading my mind. That was fast work. That coil probably got you closer to were Homer first suggested...as the possible fix he suggested.
You might be able to get the match near perfect if you raise the antenna a bit to allow for some more radial angle, even with only 1 radial, slanted down at the correct angle. You can also play with the length of each element from 102"/108" inches too.
The slanted down radial is what helps improve the match the most in this case. You may have to go higher to keep the radial above the ground a little however.
You might be able to get the match near perfect if you raise the antenna a bit to allow for some more radial angle, even with only 1 radial, slanted down at the correct angle. You can also play with the length of each element from 102"/108" inches too.
The slanted down radial is what helps improve the match the most in this case. You may have to go higher to keep the radial above the ground a little however.
I plan to raise it. As is on Ch 20, SWR is 1.2:1, R= 52.7, X= -5.2.
Not bad.
Not bad.
