Oh when it comes to air wound chokes it's absolutely specific as they're very narrow banded. 5 turns of RG213 on a 4.25" former gives you a RF choke that gives you 8k Ohms choking between roughly 25.5MHz-28MHz. If you increase the number of turns by just two, making it 7 turns that detunes the RF choke by 6MHz so your 8k Ohms choking is now between 19MHz-21MHz.
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Oh when it comes to air wound chokes it's absolutely specific as they're very narrow banded. 5 turns of RG213 on a 4.25" former gives you a RF choke that gives you 8k Ohms choking between roughly 25.5MHz-28MHz. If you increase the number of turns by just two, making it 7 turns that detunes the RF choke by 6MHz so your 8k Ohms choking is now between 19MHz-21MHz.
Okay update... it rained like an absolute bitch this morning. I turned on my radio and keyed up with high power and guess what? SWR is almost flat near ch20. This tells me it is indeed a ground thing going on since the soil is moist. Definitely installing a few ground rods asap to see if that does the same as the moist ground. I was getting my previous results from dry soil on hot days so there must be something to that.
An update of sorts:
Just installed a 6' ground rod at the tower base using the watering method, went down in under 10 minutes with a 4lb sledge hammer, so thumbs up for the watering the hole method.
However after strapping it to the tower and coming inside, SWR is the same as before at 1.08 or so on ch20, and 1.15 at channel edges. If I remove that wire attached to the tower though the SWR goes back up some, so the wire is definitely doing something odd that even a ground rod isn't replacing or helping with, but at least now I will feel a little more comfortable when storms come through.
It's unfortunate that reading one of the replies here suggests my 20' tower with the now ground rod installed is somehow a bad length. SWR looks great and my added wire gimmick seems to help. I certainly am not experiencing bad CMC that I can tell. I really don't want to go down to 10' of tower, nor do I want to add more length since it's already a PITA to get it up on that 20' worth with my limited tooling. I have a bad feeling that if I were to mess with things further by adding height it might just make things worse, or as they say.. if it's not broke.. ?
Makes me wonder what other peoples experiences are with EFHW 11m antennas mounted around 20', no CMC choke, non-isolated, and soil grounded?
Just installed a 6' ground rod at the tower base using the watering method, went down in under 10 minutes with a 4lb sledge hammer, so thumbs up for the watering the hole method.
However after strapping it to the tower and coming inside, SWR is the same as before at 1.08 or so on ch20, and 1.15 at channel edges. If I remove that wire attached to the tower though the SWR goes back up some, so the wire is definitely doing something odd that even a ground rod isn't replacing or helping with, but at least now I will feel a little more comfortable when storms come through.
It's unfortunate that reading one of the replies here suggests my 20' tower with the now ground rod installed is somehow a bad length. SWR looks great and my added wire gimmick seems to help. I certainly am not experiencing bad CMC that I can tell. I really don't want to go down to 10' of tower, nor do I want to add more length since it's already a PITA to get it up on that 20' worth with my limited tooling. I have a bad feeling that if I were to mess with things further by adding height it might just make things worse, or as they say.. if it's not broke.. ?
Makes me wonder what other peoples experiences are with EFHW 11m antennas mounted around 20', no CMC choke, non-isolated, and soil grounded?
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Darklife, below is a link to some threads on this forum about EFHW antennas, including your threads. May not be a one that gives an answer to your questions, but you might find something interesting.
https://www.worldwidedx.com/search/67673346/?q=EFHW+antennas&o=date&c[node]=79
https://www.worldwidedx.com/search/67673346/?q=EFHW+antennas&o=date&c[node]=79
I can't believe this, I think my POS dirt cheap SWR meter I've relied on for years might be faulty. I tuned up the whole antenna almost a foot short because that was what showed best SWR, then little weird things like this post popped out of the strange occurrences I was experiencing. I didn't think I could rely on my built-in Anytone 5555n SWR meter as it was a bit off from my old meter.... until I tested my trusty old homemade tandem match SWR meter. Found the tandem was giving me the exact same readings as the radios built-in meter, but that cheap dollar CB shop meter wasn't showing the same.
Ugh back out to retune the antenna again. Now I feel like a dunce.
Ugh back out to retune the antenna again. Now I feel like a dunce.
Darklife it happens. All part of the wonderful hobby.
I was building an 15 meter vertical, my 12 year old son in the shack checking vswr.
No matter where I adjusted the antenna my son said I had a 1:1 match.
After about 30 minutes of scratching my head and thinking I might have found the silver bullet for an all band no trap vertical I decided to walk in the shack and see what was really happening.
My son had turned the coax switch to dummy load position and I had great vswr no matter what frequency I was on.
I ordered an antenna analyzer the next day.
I was building an 15 meter vertical, my 12 year old son in the shack checking vswr.
No matter where I adjusted the antenna my son said I had a 1:1 match.
After about 30 minutes of scratching my head and thinking I might have found the silver bullet for an all band no trap vertical I decided to walk in the shack and see what was really happening.
My son had turned the coax switch to dummy load position and I had great vswr no matter what frequency I was on.
I ordered an antenna analyzer the next day.
Before I got an antenna analyzer I would tape the PTT button closed on my radio and lay the microphone next to the scanner and press the VOX switch. Then I would take the handheld out to the yard and program in some obscure frequency into it and the scanner. I could then place my SWR meter at the feedpoint and remotely trigger the TX from the yard using the HT. It was crude but it worked. Just make sure you don't have the coax disconnected when the phone rings.
Try ground tower with another ground. Mine down same thing. Need 10 foot ground rod
I'm giving up on this for the time being until I either get an antenna analyzer or try a coax choke.
I have absolutely no idea why two different SWR meters are showing different readings for different frequencies on the same length of 80' coax. One showing the SWR is lower on low channels, the other showing it's low on high channels.
Both meters test perfectly fine into a dummy load so that leads me to think maybe one of the meters (probably the cheapy one) is being effected by coax common mode current even after the long coax run.
I just went with an SWR reading somewhere between the two meters and what my radios built in meter was happy with, which seems to work okay for now.
Really I shouldn't freak out over this, everything is below 1.5:1 for CB, but I know it can be better and eventually peaked for midband once these mysteries are solved.
The ladder or wire hanging off the tower still has a slight improvement in lowering "swers" for some bizarre reason
I have absolutely no idea why two different SWR meters are showing different readings for different frequencies on the same length of 80' coax. One showing the SWR is lower on low channels, the other showing it's low on high channels.
Both meters test perfectly fine into a dummy load so that leads me to think maybe one of the meters (probably the cheapy one) is being effected by coax common mode current even after the long coax run.
I just went with an SWR reading somewhere between the two meters and what my radios built in meter was happy with, which seems to work okay for now.
Really I shouldn't freak out over this, everything is below 1.5:1 for CB, but I know it can be better and eventually peaked for midband once these mysteries are solved.
The ladder or wire hanging off the tower still has a slight improvement in lowering "swers" for some bizarre reason
if vswr ia 1.5:1 trying to get it lower will make no difference on the receive end.
The A99 clone may just be the best you get on 11 meter freq for vswr.
I wouldn't sweat it, just get on the air and make some contacts and yes it may be CMC,
install your A99 copy using a top stick of chain link fence available at lowes or home depot..
run the coax up inside the pipe and it will act as a shield or sleeve balun per say.
you also get some more height on the antenna.
The A99 clone may just be the best you get on 11 meter freq for vswr.
I wouldn't sweat it, just get on the air and make some contacts and yes it may be CMC,
install your A99 copy using a top stick of chain link fence available at lowes or home depot..
run the coax up inside the pipe and it will act as a shield or sleeve balun per say.
you also get some more height on the antenna.
Okay I have been at my wits end with this antenna. I am sure it has been my install, but things definitely didn't go as planned.
I want to make it clear right now that the adjustment for this antenna and the Antron 99-A and other antennas have a major flaw. Tower height, coax length, and grounding.
I can't believe the hell I went through in the last week trying to narrow down these things. I installed a 6' ground rod, all seemed fine and didn't change things, until I realized I had two SWR meters reading different measurements at different frequencies.
This is where hell begins with antennas and I got real pissed. First I thought it was one of my SWR meters malfunctioning, but then I tested my radios built in SWR meter, it was also giving a completely different value than the other two. This was over about a 80' run of coax up 20' of tower.
I learned something valuable that I hope is heard loud and clear when it comes to these end fed antennas, DO NOT USE a wavelength of pole or tower to mount to. You really want a half-wave of height or multiple. I made a mistake and went for 20' (2' of which buried in ground), close to 18' and I could not get this damn antenna to work right. I added some coax and pushed it up 25-30 feet, it works now, the original instructions work! Height makes it work better.
Why this is remains a mystery to me given it's out in the open. All I know is I am happy the antennas element length is correct to instructions now, rather than having to shorten it by almost 6+ inches. I also coiled some coax at the base of the antenna, helped some with RFI.
I will spare everyone with the hell I went through trying to make coiled chokes and such. It's been a full day of fuckery. Just glad it works!
Thank you all for the help. If it weren't for the info in this thread I would still be lost. I'll return the favor with my knowledge when threads come up I can answer
I want to make it clear right now that the adjustment for this antenna and the Antron 99-A and other antennas have a major flaw. Tower height, coax length, and grounding.
I can't believe the hell I went through in the last week trying to narrow down these things. I installed a 6' ground rod, all seemed fine and didn't change things, until I realized I had two SWR meters reading different measurements at different frequencies.
This is where hell begins with antennas and I got real pissed. First I thought it was one of my SWR meters malfunctioning, but then I tested my radios built in SWR meter, it was also giving a completely different value than the other two. This was over about a 80' run of coax up 20' of tower.
I learned something valuable that I hope is heard loud and clear when it comes to these end fed antennas, DO NOT USE a wavelength of pole or tower to mount to. You really want a half-wave of height or multiple. I made a mistake and went for 20' (2' of which buried in ground), close to 18' and I could not get this damn antenna to work right. I added some coax and pushed it up 25-30 feet, it works now, the original instructions work! Height makes it work better.
Why this is remains a mystery to me given it's out in the open. All I know is I am happy the antennas element length is correct to instructions now, rather than having to shorten it by almost 6+ inches. I also coiled some coax at the base of the antenna, helped some with RFI.
I will spare everyone with the hell I went through trying to make coiled chokes and such. It's been a full day of fuckery. Just glad it works!
Thank you all for the help. If it weren't for the info in this thread I would still be lost. I'll return the favor with my knowledge when threads come up I can answer
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