1. Contacts are meaningless without comparison to another antenna and multiple test. 2. Checking SWR at the end of 50 feet of coax is meaningless. Impedance and SWR must be measured at the base of the antenna. Checking at the end does not take into account "transmission line transformation", copper loss and dielectric loss of the coax. 3. Impedance of a 1/4 wave ground mounted vertical should be closer to 30 ohms, not 50 ohms. Therefore, low swr can mean high ground loss or absorption by mast. 4. Some folks believe in running the wire up the center of the mast. That would be a more telling test. I saw the video of that guy sticking a short section of carbon mast through a coil. How is that proving anything? It's too short! Here's a test: Feed that mast and measure the RF current at various points using an inductive coupling to the meter. Run the same test with either a metal mast or wire supported by fiberglass or pvc. If that carbon fiber can be used as a radiator then that proves it's going to absorb RF. Remember, even if you loose 1/2 your power, that's just 3db and one S unit is 6db. That's why contacts are unreliable for this kind of test. Oh....The carbon fiber mast vendors won't like that one! :*)
Thanks but I'll leave the testing to you. It is a lot of work as you know. Some things like this don't really need testing because we already know what will happen. I guess sometimes we just want to see if we can "get by" with bad designs even if we know they aren't optimum. Several times I've accidently transmitted into a dummy load and was heard miles away! I just consider a carbon fiber mast to be a metal mast and treat it that way. They are fine for use as supports but not part of the antenna. 73
This is what the hobby is all about, in the field a lot of theory gets abandoned and contacts become the payoff. As someone said in the other comments there are some many things that effect an antenna. A dummy load will give you a perfect match but it doesn’t radiate so don’t get too hung up on trying to get a perfect 50 ohm and 0 reactance match. Great vid and well produced. 73 Mike
When I was making my QRPGuys 3-band vertical I didn't realize I had wrapped some of the 17-foot vertical around the carbon fiber fishing pole & it considerably lowered the resonate frequency, the problem I had was without winding it on a rigid firm the results weren't very repeatable so it played havoc with tuning the antenna. Then I replaced the carbon fiber pole with the MFJ-1978 telescoping antenna, but I think I got one with a bad crimp at the base be a use in the wind it was toggling about 1 MHz different in resonate frequencies each deployment for the same length. One thing about antennas is we can't get away from the wind! Cheers, Davey - KU9L
Negative reactance means capacitive reactance. It electrically shortens antenna. To counteract that, you will need to add some coil or add length to that antenna, i.e. 17 ft whip. OR cheat by using a wire that has very low velocity factor - inner core of cheap rg-58 (copper in PE insulation - just strip the shielding).
If you look at the smith chart you showed, it had the plot below the axis line. If plots are “below” or “negative numbers”, that is showing capacitive reactance. Numbers that are above the line or are positive are considered inductive reactance. Loading the system with a small coil would introduce inductance to the system, thus counteracting with the capacitive reactance. This has a “balancing” effect to the reactance, making the system resonate. Capacitive? Add inductance. Inductive? Add capacitor! One value balances the other. Your goal for antennas is to have x=zero, or j to be zero.
I used a carbon fiber mast to setup a ZSBKW/G5RV for portable use in my back yard. I set it up as an inverted v and angled the ladder down and away from the the mast. I had heard about the interaction of the fiber mast with the radiating wire. I got good swr's and made some great contacts so their might be some compromise there but it was workable. 73 Brian
I'm fairly sure I made contact with that POTA duo p2p too. Nifty to know about the carbon fiber, seem its not a worry when using the inV of EFHW carbonn fiber fishing poles though.
My feeling is that you've accurately charted most of the important "coupling" or interaction results of close-by objects to radiators. Your findings and others that I'm aware of, show that these are relatively minor for carbon fiber masts. After all, look at the affects surrounding objects, soil, height, etc. have on a dipole. Can't recall in over 65 years around the bands, not having to trim or compensate antennas in some way if I was after a near-perfect match or pure pattern. Even then, there is virtually always that unknown/unmeasurable/questionable factor. (An antenna range would be nice to have) I'm not concerned about my two GigaDude 25 masts, that will be in use soon. Many thanks for all your research, efforts and support of our ham community!!!
So happy to see the masts were delivered. I sure had fun testing and I believe I have more good information / knowledge, to continue testing. It's a blast. Thanks for your support!
Testing methodology - the best way to do testing like this is to setup 2 antennas, as much the same as possible, one with the carbon mast, the other fiberglass! Then use a DUAL receiver/dual watch rig like the 7610 or similar, so that you can see the waterfallS, plus HEAR the signals from the same radio thru headphones, recordings, etc. That is for RX. For TX, you would obviously need to switch antennas during the testing cycle. Obviously from your video it does work to some degree, but how does it compare? That remains to be seen. The other testing would be to use wsjtx, and send out CQ calls over several bands, and then use PSK reporter to see how far out you got overall, and with how strong of signals. That is a great tool for testing antennas. 73
Thanks. I think I'm going to try to get back out tomorrow because I would like to test this. One issue is, I don't have another mast. My thought was to run the test on 10m or 20 with a telescoping vertical and then the same with the cf mast. I would use wspr for the TX. I would only be able to get the antennas 100 ft apart, I think this will be okay though. Finally, I think I'll be able to have my flex remotely monitoring and recording. Thanks for the useful suggestions, and should make for a better part 2. This is the fun in learning and testing!
It will have very little effect, since I doubt that there is any actual conduction between the push-up sections unless you put metal screws into them at the joints. Anything shorter than a quarter wave section of the mast should be pretty much invisible to the antenna.
Capacitance is a natural thing in HAM radio. The most common occurrence is the capacitance coupling of the counterpoise to the ground. That capacitance appearing on the video is a natural thing in building antennas. It could occur between two wires (look at DX Commander). I would be more scared if that mast spawned an HOA than the fact it adds capacitance.
Federal law states HOAs are not allowed to ban/bar any communications such as dishes or antennas. Got the complaint from the HOA against me, then showed them the FCC regulation and my lawyer(sister) and now they are real nice to me so I don't report them and cause them to get fined.
Got that regulation number handy? I know they can't ban people from reasonable sized dishes and TV antennas, but larger ones can be currently as it stands. There was a proposal that is trying to get through that would ban HOA's from saying no, but I never heard it passed this year. Please assist if you can cause I'd love to tell my HOA to hush up, lol
@@HAMRADIODUDE Over-the-Air Reception Devices Rule Over-the-Air Reception Devices Rule (OTARD) - 47 CFR § 1.4000 - has been in effect since October 1996 and prohibits restrictions that impair the installation, maintenance, or use of antennas to receive video programming. Homeowners Associations cannot prohibit or adopt restrictions that: (1) unreasonably delay or prevent installation, maintenance, or use of antennas; (2) unreasonably increase the cost of installation, maintenance, or use of antennas; or (3) preclude reception of an acceptable quality signal
@HAMRADIODUDE I'm literally just getting into the hobby, learning about making my own antennas and such while building a shortwave, and have bought a couple of mobile hand-held UHF/VHF additionally.
@@theodorepollock1273 interesting. The rules specify "No. The rule does not apply to antennas used for AM/FM radio, amateur ("ham") radio (see 47 C.F.R. §97.15), Citizen's Band ("CB") radio or Digital Audio Radio Services ("DARS")." On the FCC website. If you're getting away with it, awesome. Won't fly here though. On the other hand, Congress.gov www.congress.gov › house-bill H.R.466 - 116th Congress (2019-2020): Amateur Radio Parity Act was the bill they attempted to pass, I might still be sitting somewhere, which would allow amateur radio operators rights pertaining to HOA's. Even then, I'm going to have a hard time since I live in an h o way where I don't own the land of the property around me, just the inside of the house
When I put my Ohmeter on my CF mast it measured 100K+ ohms, but wasn't sure if that would interfere. Does it interfere, does it become the radiator too? A UK Ham measured that it was only 0.1dB different than his other fiberglass mast on a vertical antenna configuration. But how does it perform? I will try it this week with my QRPGuys 40-20M 3-band vertical, I am winding toroids this weekend. Cheers es 72, Davey - KU9L ;-)
I went back out yesterday to run a few more tests and collect some information. Today, I am going in with a new clear mind and trying a few things / using wspr. Should be fun. I have a multimeter around here somewhere, I'll see if I can't test mine as well. I think I saw that video (That may be the gentleman who used the spectrum analyzer as well). Cheers.
there is an easier test.... support the wire antenna on a fibreglass pole. Measure the SWR... leave the fibreglass supported antenna up and just bring the carbon fibre pole up next to it. Re-measure the SWR. If there is no change the carbon fibre isn't part of the antenna & you are "good to go". If the SWR changes the carbon fibre is acting as a parasitic element & it is best avoided. I wouldn't mind guessing that not all "carbon fibre" supports react the same way so always worth checking. One thing to watch for... if the carbon fibre isn't properly conductive it could be lossy, in which case it can actually widen bandwidths & IMPROVE SWR in certain circumstances (one of the best SWR's is actually found on a dummy load).
The question isn’t “is there a difference@ the question is “is there a material difference that would cause me not to use a carbon fiber mast”. So far, the answer is no.
1. Contacts are meaningless without comparison to another antenna and multiple test.
2. Checking SWR at the end of 50 feet of coax is meaningless. Impedance and SWR must be measured at the base of the antenna. Checking at the end does not take into account "transmission line transformation", copper loss and dielectric loss of the coax.
3. Impedance of a 1/4 wave ground mounted vertical should be closer to 30 ohms, not 50 ohms. Therefore, low swr can mean high ground loss or absorption by mast.
4. Some folks believe in running the wire up the center of the mast. That would be a more telling test.
I saw the video of that guy sticking a short section of carbon mast through a coil. How is that proving anything? It's too short!
Here's a test: Feed that mast and measure the RF current at various points using an inductive coupling to the meter. Run the same test with either a metal mast or wire supported by fiberglass or pvc. If that carbon fiber can be used as a radiator then that proves it's going to absorb RF.
Remember, even if you loose 1/2 your power, that's just 3db and one S unit is 6db. That's why contacts are unreliable for this kind of test.
Oh....The carbon fiber mast vendors won't like that one! :*)
You seem to have a decent following and knowledge...Would you like me to loan you one to conduct tests?
Thanks but I'll leave the testing to you. It is a lot of work as you know.
Some things like this don't really need testing because we already know what will happen. I guess sometimes we just want to see if we can "get by" with bad designs even if we know they aren't optimum. Several times I've accidently transmitted into a dummy load and was heard miles away!
I just consider a carbon fiber mast to be a metal mast and treat it that way. They are fine for use as supports but not part of the antenna. 73
I enjoy your conversational manner on these videos. I tell my wife you’re the humblest ham radio UA-camr. Keep up the good work.
This is what the hobby is all about, in the field a lot of theory gets abandoned and contacts become the payoff. As someone said in the other comments there are some many things that effect an antenna. A dummy load will give you a perfect match but it doesn’t radiate so don’t get too hung up on trying to get a perfect 50 ohm and 0 reactance match. Great vid and well produced. 73 Mike
When I was making my QRPGuys 3-band vertical I didn't realize I had wrapped some of the 17-foot vertical around the carbon fiber fishing pole & it considerably lowered the resonate frequency, the problem I had was without winding it on a rigid firm the results weren't very repeatable so it played havoc with tuning the antenna. Then I replaced the carbon fiber pole with the MFJ-1978 telescoping antenna, but I think I got one with a bad crimp at the base be a use in the wind it was toggling about 1 MHz different in resonate frequencies each deployment for the same length. One thing about antennas is we can't get away from the wind! Cheers, Davey - KU9L
Thanks for the info, it's something to be aware of!
Negative reactance means capacitive reactance. It electrically shortens antenna. To counteract that, you will need to add some coil or add length to that antenna, i.e. 17 ft whip. OR cheat by using a wire that has very low velocity factor - inner core of cheap rg-58 (copper in PE insulation - just strip the shielding).
Thank you for this. It's good information and I think you made it easy and straight to the point to understand
If you look at the smith chart you showed, it had the plot below the axis line. If plots are “below” or “negative numbers”, that is showing capacitive reactance. Numbers that are above the line or are positive are considered inductive reactance.
Loading the system with a small coil would introduce inductance to the system, thus counteracting with the capacitive reactance. This has a “balancing” effect to the reactance, making the system resonate. Capacitive? Add inductance. Inductive? Add capacitor! One value balances the other.
Your goal for antennas is to have x=zero, or j to be zero.
It's always fun experimenting and trying things with antennas.
I used a carbon fiber mast to setup a ZSBKW/G5RV for portable use in my back yard. I set it up as an inverted v and angled the ladder down and away from the the mast. I had heard about the interaction of the fiber mast with the radiating wire. I got good swr's and made some great contacts so their might be some compromise there but it was workable. 73 Brian
I'm fairly sure I made contact with that POTA duo p2p too. Nifty to know about the carbon fiber, seem its not a worry when using the inV of EFHW carbonn fiber fishing poles though.
You can buy a carbon fiber pole at any window cleaning supply store up to 60 feet.
Cool
Love my dude spike! patiently waiting to order my GigaDude mast.
I have a 33’ DX Engineering carbon fiber and I have no real issues.
Glad to read that, I have the same one arriving here today.
Not only is it still usable, you can use the mast itself as an antenna!
My feeling is that you've accurately charted most of the important "coupling" or interaction results of close-by objects to radiators. Your findings and others that I'm aware of, show that these are relatively minor for carbon fiber masts. After all, look at the affects surrounding objects, soil, height, etc. have on a dipole. Can't recall in over 65 years around the bands, not having to trim or compensate antennas in some way if I was after a near-perfect match or pure pattern. Even then, there is virtually always that unknown/unmeasurable/questionable factor. (An antenna range would be nice to have) I'm not concerned about my two GigaDude 25 masts, that will be in use soon. Many thanks for all your research, efforts and support of our ham community!!!
So happy to see the masts were delivered. I sure had fun testing and I believe I have more good information / knowledge, to continue testing. It's a blast. Thanks for your support!
Testing methodology - the best way to do testing like this is to setup 2 antennas, as much the same as possible, one with the carbon mast, the other fiberglass! Then use a DUAL receiver/dual watch rig like the 7610 or similar, so that you can see the waterfallS, plus HEAR the signals from the same radio thru headphones, recordings, etc. That is for RX.
For TX, you would obviously need to switch antennas during the testing cycle.
Obviously from your video it does work to some degree, but how does it compare? That remains to be seen.
The other testing would be to use wsjtx, and send out CQ calls over several bands, and then use PSK reporter to see how far out you got overall, and with how strong of signals. That is a great tool for testing antennas.
73
Thanks. I think I'm going to try to get back out tomorrow because I would like to test this. One issue is, I don't have another mast. My thought was to run the test on 10m or 20 with a telescoping vertical and then the same with the cf mast. I would use wspr for the TX. I would only be able to get the antennas 100 ft apart, I think this will be okay though. Finally, I think I'll be able to have my flex remotely monitoring and recording. Thanks for the useful suggestions, and should make for a better part 2. This is the fun in learning and testing!
If carbon fibre is RF conductive try connecting straight onto the carbon fibre with a clamp .
It will have very little effect, since I doubt that there is any actual conduction between the push-up sections unless you put metal screws into them at the joints. Anything shorter than a quarter wave section of the mast should be pretty much invisible to the antenna.
That's my pal, damn it!
"Da HAM Radio Dude just rules" that's all da Florida I am saying ...over over. 💯👍🙋♂
I sure hope not. I paid like $80 for my Japanese fishing pole antenna mast. Lol
Capacitance is a natural thing in HAM radio. The most common occurrence is the capacitance coupling of the counterpoise to the ground. That capacitance appearing on the video is a natural thing in building antennas. It could occur between two wires (look at DX Commander). I would be more scared if that mast spawned an HOA than the fact it adds capacitance.
Good test!
Federal law states HOAs are not allowed to ban/bar any communications such as dishes or antennas. Got the complaint from the HOA against me, then showed them the FCC regulation and my lawyer(sister) and now they are real nice to me so I don't report them and cause them to get fined.
Got that regulation number handy? I know they can't ban people from reasonable sized dishes and TV antennas, but larger ones can be currently as it stands. There was a proposal that is trying to get through that would ban HOA's from saying no, but I never heard it passed this year. Please assist if you can cause I'd love to tell my HOA to hush up, lol
Which federal law is that?.
@@HAMRADIODUDE Over-the-Air Reception Devices Rule
Over-the-Air Reception Devices Rule (OTARD) - 47 CFR § 1.4000 - has been in effect since October 1996 and prohibits restrictions that impair the installation, maintenance, or use of antennas to receive video programming.
Homeowners Associations cannot prohibit or adopt restrictions that: (1) unreasonably delay or prevent installation, maintenance, or use of antennas; (2) unreasonably increase the cost of installation, maintenance, or use of antennas; or (3) preclude reception of an acceptable quality signal
@HAMRADIODUDE I'm literally just getting into the hobby, learning about making my own antennas and such while building a shortwave, and have bought a couple of mobile hand-held UHF/VHF additionally.
@@theodorepollock1273 interesting. The rules specify "No. The rule does not apply to antennas used for AM/FM radio, amateur ("ham") radio (see 47 C.F.R. §97.15), Citizen's Band ("CB") radio or Digital Audio Radio Services ("DARS")." On the FCC website. If you're getting away with it, awesome. Won't fly here though. On the other hand, Congress.gov
www.congress.gov › house-bill
H.R.466 - 116th Congress (2019-2020): Amateur Radio Parity Act was the bill they attempted to pass, I might still be sitting somewhere, which would allow amateur radio operators rights pertaining to HOA's. Even then, I'm going to have a hard time since I live in an h o way where I don't own the land of the property around me, just the inside of the house
DR-8 is the reel, the black wire is called WD-1 wire
Thank you!
@@HAMRADIODUDE good video, looked like fun.
When I put my Ohmeter on my CF mast it measured 100K+ ohms, but wasn't sure if that would interfere. Does it interfere, does it become the radiator too? A UK Ham measured that it was only 0.1dB different than his other fiberglass mast on a vertical antenna configuration. But how does it perform? I will try it this week with my QRPGuys 40-20M 3-band vertical, I am winding toroids this weekend. Cheers es 72, Davey - KU9L ;-)
I went back out yesterday to run a few more tests and collect some information. Today, I am going in with a new clear mind and trying a few things / using wspr. Should be fun. I have a multimeter around here somewhere, I'll see if I can't test mine as well. I think I saw that video (That may be the gentleman who used the spectrum analyzer as well). Cheers.
What did ya'll find from the follow-ups? :)
Where did you get the jp12 thread adapter?
www.aliexpress.com/item/1005005037034161.html
there is an easier test.... support the wire antenna on a fibreglass pole. Measure the SWR... leave the fibreglass supported antenna up and just bring the carbon fibre pole up next to it. Re-measure the SWR. If there is no change the carbon fibre isn't part of the antenna & you are "good to go". If the SWR changes the carbon fibre is acting as a parasitic element & it is best avoided. I wouldn't mind guessing that not all "carbon fibre" supports react the same way so always worth checking.
One thing to watch for... if the carbon fibre isn't properly conductive it could be lossy, in which case it can actually widen bandwidths & IMPROVE SWR in certain circumstances (one of the best SWR's is actually found on a dummy load).
Oh wow. This would be a lot easier. Thank You!
Great job. Don't sweat the complainers. As esteemed poet T. Swift once noted, "Haters gonna hate hate hate hate hate...." 🤣 K7KS
T Swift, - a Modern Day Hemingway
The question isn’t “is there a difference@ the question is “is there a material difference that would cause me not to use a carbon fiber mast”. So far, the answer is no.
I would say screw the Smith Chart....you made several contacts so its fine!!!!
Hope that jug of H2O was ....POTAble
😂😂😂😂🤣🤣🤣.. You win
tune the antenna to the mast
It won't. even those it's conductive, It's not conductive like a piece of copper or anything. Cheers/
Mine must be a fluke then@@HAMRADIODUDE
you dont understand never mind@@HAMRADIODUDE
Fiberglass masts work. Aluminum masts work. Carbon Fiber shouldn't be a peoblem.
They're too dern pricey.
Hey Dude a teaspoon of honey every morning with help your hayfeaver.
Thank You!
locally sourced honey*