The tests were using faraday cloth as the ground radial. I will be testing it with the Pota Performer in the next few days and this will perhaps assist those using elevated radials.
I received my 40 meter coil with 10 windings for my Chameleon SS-25. Thank you for the quick shipping and great packaging.
With the SS-25 fully extended it was resonant at about 6.8 MHZ. I removed two windings for a total of 8 windings remaining and the coil now is perfect. At 7.10 MHZ the SWR is 1.4. From 7.2 through 7.30 MHZ the SWR is 1.5 with the SS-25 fully extended.
I removed the coil windings at a half of winding per test. Removing two full windings worked best for me. I tested it with two different soil types, one clay soil near Hollister, Ca and one test in more rocky soil in the gold country just north-east of Sacramento.
I like the small format of the coil and being able to use the fully extender SS-25. In the past I used my Wolf River Coils 1000. This is more compact.
I just ordered a 40 meter coil. Your site says that if I notify you, I can change this order to a 10 wrap coil to adapt to the Chameleon SS-25. Please send me a 10 wrap coil. Thank you. This is Jack Kirk Sr, W6KRK
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.
The tests were using faraday cloth as the ground radial. I will be testing it with the Pota Performer in the next few days and this will perhaps assist those using elevated radials.
Gary,
I received my 40 meter coil with 10 windings for my Chameleon SS-25. Thank you for the quick shipping and great packaging.
With the SS-25 fully extended it was resonant at about 6.8 MHZ. I removed two windings for a total of 8 windings remaining and the coil now is perfect. At 7.10 MHZ the SWR is 1.4. From 7.2 through 7.30 MHZ the SWR is 1.5 with the SS-25 fully extended.
I removed the coil windings at a half of winding per test. Removing two full windings worked best for me. I tested it with two different soil types, one clay soil near Hollister, Ca and one test in more rocky soil in the gold country just north-east of Sacramento.
I like the small format of the coil and being able to use the fully extender SS-25. In the past I used my Wolf River Coils 1000. This is more compact.
Hope this helps.
Jack
Gary,
I just ordered a 40 meter coil. Your site says that if I notify you, I can change this order to a 10 wrap coil to adapt to the Chameleon SS-25. Please send me a 10 wrap coil. Thank you. This is Jack Kirk Sr, W6KRK
Nice "Contact" movie quote by John Hurt. Love it!! K7KS
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.