Great video. This is the most conclusive evidence I've seen of the impact a carbon fiber pole has on an antenna. When the weather warms, I want to do similar testing on my sloped antennas.
This is very good -- though it's quite obvious that the return loss (SWR) curve changes only when the objects are VERY close, and practically touching. Even a few inches seems to avoid a severe detuning (and presumably decoupling). It's not very clear to me what the likely impact is from a received signal strength perspective, for both incoming and outgoing signals, as long as the conductive materials are not essentially touching.
The return loss, with its sensitivity of conductive (and dielectric really) objects in the near field of the antenna giving us a way to compare materials in an RF sense. The moral of the story is the carbon fiber mast acts a lot like a conductive metal mast. With that knowledge, we can plan our antenna system... for example using the carbon fiber mast like we would use a metal one... perhaps as a support for the center of a dipole.
@@SkyCharter I appreciate the reply, which is both sensible and well thought out. That would be my primary plan (inland and above typical soil), but I am scheming on best possible ways to use my new Pota20 carbon fiber mast at the beach, close to the water line and likely with a seawater ground connection just under the waterline. This would make vertical polarization ideal. It may not be the ideal support, but the appeal is the size/weight. While I'm talking about HF, while your test was VHF, it's very clear that the pole will be very much in the near field.
Thanks for the video - very helpful! I have a SOTABeams Carbon6 which I plan on using for an inverted V random wire end fed antenna, so I’m glad to hear that the mast will work fine in this configuration. Your video was invaluable to ensure that I don’t try to use it in a vertically polarized configuration. Great work! 73, Mark K0EHR
If we use a carbon fiber mast in the usual expected fashion, we attach a vertical antenna at the TOP of the mast. The antenna is far away from the carbon fiber pole. The antenna is NOT lying parallel and/or adjacent to the carbon fiber pole. Could you please repeat the experiment with the antenna attached at the TOP of the carbon fiber pole and see what results you get? That would be the truly relevant test. Thanks for your great work.
So short sections of carbon fiber golf club shafts used as spacers for home built ladder line with insulated wire or folded dipole element separators with insulated wires SHOULD be benign? Or would it add large capacitance? Surely it would not re-radiate HF since only a few inches long and perpendicular, right?
It seems like the two important points from the video regarding the effects are that: 1. The assumption is that the mast material and the antenna are parallel. 2. The mast is in very close proximity to the antenna. So, what happens if the antenna on atop the mast instead of hanging parallel to it?
The parallel test arrangement certainly is to maximally couple mast and radiator... mostly to demonstrate the mast's conductivity and dissuade those who think carbon fiber masts don't conduct at all. For typical center-fed dipole hoisting, the carbon mast should be fine... as would a metal mast.
Very good test. Thank you for doing this experiment and sharing the data. You should send this data to Gigaparts re: their 34 foot carbon fiber multi-section mast product.
Great test but possibly only valid for that style of antenna? A random wire or EFHW in one of the HF bands running straight up the pole would be a good test to run too.
New subscriber here. Thanks for the video. I am new to ham radio and considering what sort of mast to use (mainly for portable use). I wonder how far away the antenna can be from a conductive surface like the carbon fiber pole or a metal tower where it would not de tune the antenna.
Hello, thank you so much for the information and the experience. I have a question for you as an expert, I want to use a mast to used for mounting cellular signal booster antenna weboost , also for mounting some wifi antenna from Ubiquiti. Is the carbon fiber will effect negatively on the performance of the antenna devices? Thank you
I suspect the cellular antenna is designed to mount atop a study mast made of anything conductive or not so the antenna is well away from the mast's effect. It's probably fine, but testing is the ultimate truth.
Great testing method.
Very nicely done.
Great video. This is the most conclusive evidence I've seen of the impact a carbon fiber pole has on an antenna. When the weather warms, I want to do similar testing on my sloped antennas.
That will be interesting. It should work well, but testing is always interesting.
This is very good -- though it's quite obvious that the return loss (SWR) curve changes only when the objects are VERY close, and practically touching. Even a few inches seems to avoid a severe detuning (and presumably decoupling). It's not very clear to me what the likely impact is from a received signal strength perspective, for both incoming and outgoing signals, as long as the conductive materials are not essentially touching.
The return loss, with its sensitivity of conductive (and dielectric really) objects in the near field of the antenna giving us a way to compare materials in an RF sense. The moral of the story is the carbon fiber mast acts a lot like a conductive metal mast. With that knowledge, we can plan our antenna system... for example using the carbon fiber mast like we would use a metal one... perhaps as a support for the center of a dipole.
@@SkyCharter I appreciate the reply, which is both sensible and well thought out. That would be my primary plan (inland and above typical soil), but I am scheming on best possible ways to use my new Pota20 carbon fiber mast at the beach, close to the water line and likely with a seawater ground connection just under the waterline. This would make vertical polarization ideal. It may not be the ideal support, but the appeal is the size/weight.
While I'm talking about HF, while your test was VHF, it's very clear that the pole will be very much in the near field.
Awesome video! Experiments like this are needed!
More to come!
Thanks for the video - very helpful! I have a SOTABeams Carbon6 which I plan on using for an inverted V random wire end fed antenna, so I’m glad to hear that the mast will work fine in this configuration. Your video was invaluable to ensure that I don’t try to use it in a vertically polarized configuration. Great work! 73, Mark K0EHR
Glad it helped
Very cool Alan - seems definitive! Thanks for sharing.
Who's Alan?
@@SkyCharter Sorry typo ... YOU ... John
Thanks for taking the time to test this. Learned this long ago but I never have tested it.
Nice test! I wonder what effect carbon fiber would have HF frequencies ?
If we use a carbon fiber mast in the usual expected fashion, we attach a vertical antenna at the TOP of the mast. The antenna is far away from the carbon fiber pole. The antenna is NOT lying parallel and/or adjacent to the carbon fiber pole. Could you please repeat the experiment with the antenna attached at the TOP of the carbon fiber pole and see what results you get? That would be the truly relevant test. Thanks for your great work.
Can a carbon fiber pole be used to mount the MLA-30 antenna?
Useful content. So is your conclusion your final antler?
So short sections of carbon fiber golf club shafts used as spacers for home built ladder line with insulated wire or folded dipole element separators with insulated wires SHOULD be benign? Or would it add large capacitance? Surely it would not re-radiate HF since only a few inches long and perpendicular, right?
Damn, I really need to get that wooden walking stick. It significantly improves the antenna and acts like a Q muliplier.
It seems like the two important points from the video regarding the effects are that:
1. The assumption is that the mast material and the antenna are parallel.
2. The mast is in very close proximity to the antenna.
So, what happens if the antenna on atop the mast instead of hanging parallel to it?
The parallel test arrangement certainly is to maximally couple mast and radiator... mostly to demonstrate the mast's conductivity and dissuade those who think carbon fiber masts don't conduct at all. For typical center-fed dipole hoisting, the carbon mast should be fine... as would a metal mast.
Very good test. Thank you for doing this experiment and sharing the data. You should send this data to Gigaparts re: their 34 foot carbon fiber multi-section mast product.
Thanks for the comment. I'll let others share this where they think appropriate... but I get your point.
I suspect Gigaparts didn't test their mast at a distance of two inches from a Slim Jim. There are other use cases for those masts.
Great test but possibly only valid for that style of antenna? A random wire or EFHW in one of the HF bands running straight up the pole would be a good test to run too.
Good idea.
New subscriber here. Thanks for the video. I am new to ham radio and considering what sort of mast to use (mainly for portable use). I wonder how far away the antenna can be from a conductive surface like the carbon fiber pole or a metal tower where it would not de tune the antenna.
Hello, thank you so much for the information and the experience.
I have a question for you as an expert, I want to use a mast to used for mounting cellular signal booster antenna weboost , also for mounting some wifi antenna from Ubiquiti.
Is the carbon fiber will effect negatively on the performance of the antenna devices?
Thank you
I suspect the cellular antenna is designed to mount atop a study mast made of anything conductive or not so the antenna is well away from the mast's effect. It's probably fine, but testing is the ultimate truth.
Maybe you should've worn insulating gloves when conducting your tests
Perhaps. At wavelengths like this, however, the same effect should be visible.
@@SkyCharter Were those antlers from a carbon fiber whitetail, or...?
Junk science.... at its worst.... waste of our time... What happens when a ham operator thinks he knows all about testing antennas...
Please explain your qualifications to make this assessment.
The experiment seemed valid to me....how can you argue with these VNA findings?