I saw Michael, KB9VBR mention your coil on his video, and decided to check into it. How well does your coil perform with the 25-foot whip in a typical POTA Performer type setup?
Hi Chris! I haven't tried it (no 25 ft whip). Based on other reports, it works fine so long as follow the directions by using an appropriate length radial and reduce the windings to 10 turns.
I re-wound the coil this week with 18 turns (17 turns and 2 half turns, slightly smaller 14AWG .0591) and finally got the 40m band under 2.0:1 by adding 49 inches to the elevated radial (you were right)!
40M, SWR 1.9, 7.00 mHz
40M, SWR 1.6, 7.20 mHz
I can live with these results.
Now it’s on to Field trials on 40m to see how the contacts go.
Thanks for hanging in there Bob! I tested with a 17' Chameleon whip.
I've noticed quite a bit of variance depending on quality of ground and radials. It sounds like you found the "dip" at 17 turns, but the dip wasn't as low as you'd hoped. I understand. This might be a good time to experiment with extra ground radials, or trying a different location with different soil.
Did you test this with your whip? The best I could get with the original design was 2.2 to one. I took off a winding and it went to 2.5 then I went the other way to 18 windings and it went to 3.0 so I’m a little lost. Not sure how many iterations of this process will need to do, but I will keep trying..
I built this and it had 10.5µH of inductance. With my CHA SS17 whip fully extended it had the lowest SWR at 6.645 MHz. I needed to collapse two sections to get it resonant on the 40m band. I backed out one full turn of the winding to get 8.9µH. I need to test this with my whip but I'm surprised with this result. I would have expected needing more inductance with a 17' whip.
Your induction measurement is close to my own. I've had to tuck in more of the whip than I wanted to on occasion as well. Not every time, but it does happen. I usually attribute it to the quality of my ground plane and the [less than ideal] grounding qualities of the surface I mount the antenna on.
Gary,
I saw Michael, KB9VBR mention your coil on his video, and decided to check into it. How well does your coil perform with the 25-foot whip in a typical POTA Performer type setup?
73,
Chris, NS8Q
Hi Chris! I haven't tried it (no 25 ft whip). Based on other reports, it works fine so long as follow the directions by using an appropriate length radial and reduce the windings to 10 turns.
Thanks, Gary!
I re-wound the coil this week with 18 turns (17 turns and 2 half turns, slightly smaller 14AWG .0591) and finally got the 40m band under 2.0:1 by adding 49 inches to the elevated radial (you were right)!
40M, SWR 1.9, 7.00 mHz
40M, SWR 1.6, 7.20 mHz
I can live with these results.
Now it’s on to Field trials on 40m to see how the contacts go.
73s
Bob, WB0WIF
Thanks for hanging in there Bob! I tested with a 17' Chameleon whip.
I've noticed quite a bit of variance depending on quality of ground and radials. It sounds like you found the "dip" at 17 turns, but the dip wasn't as low as you'd hoped. I understand. This might be a good time to experiment with extra ground radials, or trying a different location with different soil.
Did you test this with your whip? The best I could get with the original design was 2.2 to one. I took off a winding and it went to 2.5 then I went the other way to 18 windings and it went to 3.0 so I’m a little lost. Not sure how many iterations of this process will need to do, but I will keep trying..
I built this and it had 10.5µH of inductance. With my CHA SS17 whip fully extended it had the lowest SWR at 6.645 MHz. I needed to collapse two sections to get it resonant on the 40m band. I backed out one full turn of the winding to get 8.9µH. I need to test this with my whip but I'm surprised with this result. I would have expected needing more inductance with a 17' whip.
Which type of Loctite would you suggest for this project?
Sorry for the late reply. I'm sure anything will work, but I use the red 271.
Thanks for sharing Pete.
Your induction measurement is close to my own. I've had to tuck in more of the whip than I wanted to on occasion as well. Not every time, but it does happen. I usually attribute it to the quality of my ground plane and the [less than ideal] grounding qualities of the surface I mount the antenna on.