I just built one of these and tested with nano VNA meeting or exceeding the results on TRX bench. As well built as yours is it will have no difficulty with common mode rejection. The wire diameter will not affect the inductance much. I did a through test with VNA to get |S21| and |S11| at several frequencies. K6JCA shows how to calculate the power gain (loss) from those parameters . 1- the power gain is the power dissipated in the balun if it is feeding a 50 Ohm load. The balun dissipates 1/2 Watt at 160 meters and progressively more power to almost 4 Watts on 10 meters assuming 100 Watts in. On 6 meters it would dissipate almost 7 Watts. For higher frequencies fewer turns with larger wire would reduce this power dissipation at the expense of not attenuating common mode at lower frequencies. W5PZT
awesome, thanks for your comment ! I made another video demontrating the attenuation factor and it is quite effective well below 20dB, you can find it in my ham radio playlist ! the balun as been installed on a small compact 2el yagi that cover 40/20/17/15 and it works wonderfully well even at 600W+. 73 !
Hello Claude, thanks for posting this video of your very neat looking common mode choke. I'm also building some common mode chokes of the same design using silver plated copper wire with teflon insulation and Fair-Rite Mix 31 ferrite material. To do the tests I have bought a thing called a NanoVNA on eBay for about US $70 and it arrived recently. Another guy at my HAM radio club bought a NanoVNA and we saw it at our HAM club today. His is a NanoVNA and his unit came with cables and an internal battery. So have a look at eBay and you will find a NanoVNA that is quite affordable. 73, Jamie VK2YCJ
Hi Jamie, yes I am aware of this little device, there is a newer one the nanovna-f with a 4.3 inch screen, I was waiting for more developpement on that latest one before buying one. Also another beautiful device is the MINI1300 but then again, not much documentation. How have you connected everything to test common mode attenuation measurements ? 73 Claude VA2CST
I have a Nanovna, have used it to check my chokes but they are a different design. The screen of the Nanovna is small but you can get the data displayed on a PC.
Aleziss I used the VNA in two port mode, if you Google “g3txq choke” you will see a similar set up. I shorted the “input” wires to the choke and connected them to the RF output of the VNA and shorted the output leads of the choke and connected them to the other port of the VNA. In other words the choke is tested as a two terminal device. The sweep is then done plotting loss between the ports of the VNA.
thank you for your comment ! I am still waiting to measure attenuation with a nanovna and it will confirm that this type of balun is really effective. As you saw, SWR is fine so I am pretty sure the attenuation work as it has been a proven method of doing common mode attenuation.
You have 1:1 balun connected to 50 Ohm dummy load. Why would you expect any SWR other that 1:1? The common-mode choke you have does not change SWR, it suppresses any reflected power going back from the dummy. Have you tested it without balun and saw different results?
@ikatkov I know what I did built is supposed to ATTENUATE (not suppress) common mode current. Now, how can I know what I did build would not change the impedance reading thus impact the SWR readings ?? what does tell me the random ptfe wire I have is the right impedance ? What does tell me the winding with the specific unknown wire I have is the right one ? It's not even the same size as suggested by trxbench, even Peter said that one type of wire he used did NOT work you can see that in one of his previous video... the only way I could at least get the impedance question out of the way was to test if the impedance was not affected by the core and winding and it seems not. The right way to test common mode attenuation would be to use a vector network analyzer or a rf signal generator with a rf spectrum analyzer which I do not have. Do you have a way to test common mode attenuation ? If so tell me right away !!! So how can I test a dipole and see how much common mode attenuation I get by installing the choke or not ? I can't "SEE" any of this ? I don't undestand what you are saying...
The characteristic impedance of a transmission line depends on the geometry of the conductors. The coaxial cable has a certain parallel capacitance an serial inductance per length that gives it it's impedance. If you insert a twisted wire pair as shown here, it will likely have a different characteristic impedance. You could use this to calculate www.allaboutcircuits.com/tools/twisted-pair-impedance-calculator/ . When there is an interruption in a transmission line due to a change in characteristic impedance, you will have reflection and therefore a non-zero SWR.
@@ramorrisey wow... this is adding to the worries I had in regard of the impedance of the wire and how it is winded... So what I've done there might be totally wrong (or not too much since SWR seems quite ok besides 50mhz)... I did it this way to prevent wires being away from each other... the link you sent me requires quite a bit of measurement, lenght of wire, spacing between wires, how many twist, thickness of insulation... this is a bit out of my abilities, I would need a vernier, another tool I do not have... the maths are also quite crunchy, thank god for the online calculator ! So if I understand what you are saying, they "could" be twisted but would need to be identical on both sides, including lenght and twist OR I would need to leave all wires straight without twisting them and I might have better results ? I just wish I had someone who could help me with a VNA... Thanks for your comment !
The reason for 2 pairs of parallel conductors is to get close to the right characteristic impedance. At the lower end of the frequency range with relatively short conductors it will cause less of an anomally. TRX bench did test common mode impedance (as I have done with my ones), if you have used the correct core material you should be good to go.
@@g0fvt thanks for the comment. I did use the FT240-43 core as he suggested, a core I already had to make an end fed half wave antenna but decided to build that balun instead. It will be use on a 2 element 40, 20, 15, 12, 10 and 6m beam next year... as it is too cold to play in the tower right now ! As someone else mentionned in this post, twisting of the wires might not be a good idea so I will straighten these instead and keep them together with a shrink tubing.
Hello Barry, thanks for your positive comment, I know that test was not really scientific but you can check my other video where you can see the actual common mode attenuation with a nanovna which is way way better than the actual balun that came with the antenna I use it on. th-cam.com/video/k2DAyvciyow/w-d-xo.html I installed the antenna two weeks ago, a TGM Communication B-246 compact 2el beam that covers 40/20/17/15/10/6m and it works really well. Cut down all RFI I had previously in the shack too !!! You can see the antenna on my QRZ page. 73 de Claude VA2CST
Now that it's much too late for this test, there's the NanoVNA that would have been just right. Starting at around $50, it's an amazing tool. For most uses, though, connector adapters are also needed, which increases the total cost.
hi thank you for your suggestion, I indeed got the nanovna-h model but setting it up for measurements is not done easily and I get uneven results so I can't really test this properly at this time but I know this type of choke balun works really well. I'll have to make some more tests and try to make this work properly with the vna which is quite difficult not having the right adapters as you need to put resistors in the line... those nanovna's arent really precise tools...
thank you for your comment, it works really well, it's been installed on a small compact 2el yagi that covers 40/20/17/15/10/6m. I have made another video where you can see the common mode current attenuation and it is really efficient only with a single core.
The SWR doesn't tell you much about the quality of a balun: what you measure is the reflected power but you don't know how much goes out the other end and how much ends up in losses. Furthermore, the main task of a balun is to offer a balanced port (or vice versa) and this certainly does not prove to you a SWRmeter. A VNA is not mandatory: to get an idea of the losses using a SWRmeter test the balun by holding the balanced port open and then shorting it. In those cases the SWR must be infinite: the power that is not reflected ends up in losses (check a table to convert SWR to dB). Other method: make two identical balun, connect them to each other through the balanced port; with a wattmeter read the exact power of the tx and then read it again with the two baluns in the middle and connected to each other in that way. Divide the difference between the two measurements by two. Finally, to verify that the balanced port is really balanced, I recommend my article on the balun-choke test: you can find the link on my QRZ page (sorry: it's in Italian. I hope Google translate can help you). 73s.
I understand all of what you are saying. My goal with the SWR testing is because I had unkown PTFE wire and I wanted to see if it would have a bad mismatch of impedance. I KNOW this is NOT the goal of a balun. I have another video where I do test the common mode attenuation and it is really efficient and this mode of wiring is well documented for a proper choke. Last thing I would need to check, as you mention, the efficiency of the balanced work such device provide. I will look into it. If you read the video description, you will see where I got all the info from Peter's TRX Bench where he got all the info from Wolfgang DG0SG www.dg0sa.de/ now your turn, all in German. A LOT of information about baluns, chokes and measurements. Family graciouly left Wolfgang website up after he passed away. 73
I would recommend NOT tuning the VFO while the radio is keyed up. I did that with an ICOM IC-706MKIIG once and it smoked the finals. When I called ICOM and told them what happened they said never transmit while tuning the VFO. I had done it on other radios prior to that one and never had a problem. Just wanted to mention it.
thanks for the tip, as you seen though, I was at low power (10-15W) and when I ramped up the power to 100W, I did not move the vfo while transmitting. I too have a 706 and they are old radios with many of their parts being at their age limit, with the combinaison of all of this, it "might" happend but it is the first time I hear final get blown because moving a vfo while on tx. Maybe swr whent too high while you were moving around... I was with a dummy load... anyway, thank you for the tip and comment.
It could be a problem when the PA transitions from one bandpass filter to another, otherwise should not be an issue, anyone that used the earlier ham satellites with linear transponders will be familiar with using VFO while on transmit.
go see the description and go check TRX Lab video, you'll have all the details if you cannot follow and pause the video, Peter explain everything you will need to know.
I was doing short burst at 100W because my dummy load can only accept 15 watts... TRXbench states that it should handle 800-1000w and you can see that my radio does not register any SWR on HF bands at 100W. If you want more, you can stack two cores, it should handle easily 1.5kw
FWIW I have run significantly over 1kW through similar, I did wind one with PVC insulated wire, huge dielectric heating. Teflon insulated wire version did not heat significantly.
@Ralph Kluge thank you for your comment, the wire I got was like this : www.ebay.ca/itm/263758650100 but I made an error ordering 16AWG instead of 18AWG... I just noticed also that it is rated at 300V and I think Peter said that for high power, it would be better with 1KV wire... this might not fit the build if you are using really high power... In my case, I will only run 100W...
I you are in the UK, you can order it from CPC: cpc.farnell.com/c/cable-leads-connectors/cable/cable-wire/hook-up-wire?jacket-material=ptfe Also the Farnell group stock it. Just search their cable category and choose PTFE as the jacket material.
I am yet to see a video of one of these working against unwanted noise. I found a video of someone simulating noise being picked up on the coax but what if you have very bad powerline noise and the antenna is picking it up? Then i suppose a 1:1 balun will do nothing to help? Or will it? I have S9 of powerline noise right now and even when i turn off all the power to the house and use a battery. Neighbours are far away, it's defiantly dirty powerline noise, i have driven around with an AM rig in the car and it's this entire hillside and unfortunatly i live 200 yards away from the lines in question!
These are NOT to get rid of electrical noises, they are design to make a unbalanced line connect to a balanced antenna AND ATTENUATE common mode currents. I too have heavy electrical noises from hydro power, probably due to faulty isolator somewhere in the neighborhood and having a balun like this one change absolutely nothing for noise levels. I get +20dB of noise on 40m, usually +15dB on 80m each winter it is the same situation and this year again, I can't make any radio specially during evenings and nights. Beleive me, if you are searching for a solution to get rid of electrical noise, this won't do it. Get yourself a magnetic loop, those are immune to "electrical" noises as they pick up "magnetic" waves. Or if you have two HF antennas, you can get a Timewave ANC4 or a MFJ1026. Those are working ok but it requires two antennas to null electrical noises.
@@Aleziss I have decided that i am going to build an X-phase unit such as the MFJ one. There is a Russian guy selling kits, boards and ready made units but also VK5TM in Australia sells his version of the boards and has a great explanation and instruction if you google him. So do you use the X-Phaser to help with the noise? Funny that yours is from Hydro as our Hydro station is only about 5 miles away or less as the crow flies. Why would hydro be particularly noisy? Perhaps it's a coincidence? I am going to look further into it as nowhere else except this village suffers from it this bad. The entire hillside here is stupidly noisy but not worse than S7 to +9. I am starting to order the parts i need now. You don't necessarily need two full sized HF antennas. The noise is not really band specific, it is across the bands so it will tune in on any antenna. I might try an old TV Yagi as the aux antenna and point it at the power lines for the greatest source of noise. I am also wondering what the possible health implications might be. There is great debate about health concerns of living under power lines but no info that i can find on how this could be an increased hazard if the lines are particularly noisy. The noise is particularly bad around this particular set of power lines on the hillside but i can also hear it from a mile or two away from the lines.
@@Aleziss regarding the choke not stopping noise. I would have thought it might help as it is designed to only let the matched signal pass and not let anything else back down the coax. Anyway thats why i was asking, thanks for clarifying that it does not help. 73's
@@izzzzzz6 well, what I meant by "hydro" is the service provider that is called "hydro quebec", the noise don't come really from hydro power generation method but rather faulty isolators or bad transformer. The difficult task is to find where the noise comes from, it could be right in my backyard or two streets away. I sent a complaint to "hydro quebec", they do have an RF truck with a bunch of antennas, spectrum analysers and they can pin point where a source of noise could come from with directional antennas and doppler... thing is I sent that complaint over 1 year ago and it is still not fixed, S9, S15 even S20 is not rare, usually when it is really cold and dry, noise levels are extremely high to the extent I cannot use the radio on 80, 40 and sometime 20m, impossible to make any contacts. I do have a MFJ1026 but it does requires two antennas. Both antennas should pickup the same signals in order to successfully null noise. If one antenna is less effective and does not pickup what the main antenna is picking up, there won't be good result as you cannot invert and null out the noise level. This is really how it works. You can't have a full dipople as a main antenna and a small antenna as the second antenna, you won't have enough gain to pickup the noise if the second antenna is too small and is not desigh to pick the noise in the same frequency range. Users that have multiple dipoles will have the best results with those noise cancelling units. It is not as simple it looks to be. I have not got good results with the MFJ1026 just for the fact that my second antenna is way less sensitive than my main hf antenna. Good luck with the tv antenna, on my side I did try a vhf yagi as the second antenna but it did not work at all.
@@izzzzzz6 I am not sure you understand the balun correctly... the balun is used to take the unbalanced output of the radio coaxial and transform it into a balanced feed like a dipole, two equal side of wires that resonate at a particular frenquency. Any unbalancing on a dipole (for whatever reason like ice, a bird sitting on one side of the antenna, tree brannches closer to one side of the dipole than the other, and so on) will result on RF coming back on the outside of the coaxial cable, the skin effect, which is also called common mode currents. What comes back on the outside of a coaxial cable is generated by an improper balance antenna and come back as RF transmitted by your transceiver. The common mode choke will block those current on the outside of the coaxial cable at the antenna where the choke should be installed. Now receiving electrical noises from electrical arcking due to faulty isolator, faulty transformer, faulty splice and so on, is picked up by the antenna itself, just as if it was a radio transmition from another station thus come in the center of the coaxial and not from the outside of the coaxial like common mode currents. Does that makes sense ?
possible, still got 20dB+ of attenuation when I tested that choke with the nanovna, it does the job ok for my need... I think mix 52 is better for higher frequencies but to the detriment of lower frequency, the antenna I currently use run from 7 to 50 so no need for me to go below 7MHz so I might try one day with another core... but I paid 5$ for a single FT240-43 and now they are 15$ a piece... I should have bought much more back then, same goes with the other mix, price have sky rocketted over 2 years only since there is a lot of demand for those cores
@@on2mvh937 yeah specially in my antenna, it is only a dipole for 6m so not much efficiency but there is a "big gun" station in my province that run a 6el 6m on a telescopic tower and he makes many contacts every day so I guess we are too cheap for 6m hihi !
Yes... two things- you will certainly need a vna or specan to see what the common mode measures. It should be greater than -20db down or as Peter would say “it’s not doing its job” checking the SWR is only secondary to the CMC measurement. I am also surprised you used the same colored wire? Would have made me crazy! I used the same colors that Peter used, Orange/Blue PTFE. My CM 1:1 Balun checks out great. I do have a VNA and a specan - where r u located?
Hello David, thanks for your comment, I am located in Quebec Canada. As for the color, I did not mind too much, I agree it would have been easier to sort everything out for sure but at the time, I had hard time finding the right wire as per Peter description, the only color I could get back then was white ! I have a nanovna but I can't make this work properly. I am not even able to measure a coax lenght and see it's resonance. The nanovna gives me crazy SWR on a coax lenght that has a 50ohm terminaison even though my MFJ and radio SWR reading sais otherwhise. I am not mastering this properly or I have a defective nanovna unfortunately...
Aleziss Dear Alexiss, I understand. I was able to purchase the blue and orange PTFE. Online. It’s been a while. First, make sure that you are using non inductive resistor load when checking SWR. But without checking the CMC first, it’s really a waste of time. As Peter mentions many times, the first job of the “Baloon!” (Peter) is the CMC then SWR. But you must have the equipment to do so. Do you have any friends close by who would have a VNA? I have a HP8711A RF Analyzer and a specAn but we’re not close. I am in Cleveland. I also bought one of those small $ 50 nanoVna. But it died within a week. So it’s in the junk box. Good luck to you.
@@davideisenberger6197 It seems I don't have the "GAIN" on the second connector on the nanovna, I am not sure why. The only measurement I found was "LOGMAG" but I am not sure it is the right measurement. I found the "GAIN" measurement on the external software (nanovna saver) but there are big difference in reading between the nanovna and what the program read... I don't have the right adapters for the nanovna so I have to order those parts too... probably from china which will take months to arrive...
@@davideisenberger6197 Hi David, I made a follow up video using a nanovna and it seems to be working pretty well while measuring the attenuation. You can see the results here : th-cam.com/video/k2DAyvciyow/w-d-xo.html of course this is far from having high precision measuring equipement but I think it gives a rough idea of the performance. Thanks for all the previous comments !
look, I am experimenting, the only thing I can test at the moment is if thiw will cause an imbalance in the inductance or capacitance and change SWR. At this poing, it seems not to influance anything, it does not add any SWR and that was my test. If you have something to say so we can learn, please go ahead...
I just built one of these and tested with nano VNA meeting or exceeding the results on TRX bench. As well built as yours is it will have no difficulty with common mode rejection. The wire diameter will not affect the inductance much. I did a through test with VNA to get |S21| and |S11| at several frequencies. K6JCA shows how to calculate the power gain (loss) from those parameters . 1- the power gain is the power dissipated in the balun if it is feeding a 50 Ohm load. The balun dissipates 1/2 Watt at 160 meters and progressively more power to almost 4 Watts on 10 meters assuming 100 Watts in. On 6 meters it would dissipate almost 7 Watts. For higher frequencies fewer turns with larger wire would reduce this power dissipation at the expense of not attenuating common mode at lower frequencies. W5PZT
awesome, thanks for your comment ! I made another video demontrating the attenuation factor and it is quite effective well below 20dB, you can find it in my ham radio playlist ! the balun as been installed on a small compact 2el yagi that cover 40/20/17/15 and it works wonderfully well even at 600W+. 73 !
Hello Claude, thanks for posting this video of your very neat looking common mode choke. I'm also building some common mode chokes of the same design using silver plated copper wire with teflon insulation and Fair-Rite Mix 31 ferrite material. To do the tests I have bought a thing called a NanoVNA on eBay for about US $70 and it arrived recently. Another guy at my HAM radio club bought a NanoVNA and we saw it at our HAM club today. His is a NanoVNA and his unit came with cables and an internal battery. So have a look at eBay and you will find a NanoVNA that is quite affordable. 73, Jamie VK2YCJ
Hi Jamie, yes I am aware of this little device, there is a newer one the nanovna-f with a 4.3 inch screen, I was waiting for more developpement on that latest one before buying one. Also another beautiful device is the MINI1300 but then again, not much documentation.
How have you connected everything to test common mode attenuation measurements ?
73 Claude VA2CST
@@Aleziss Hello Claude, I haven't tested the chokes with the VNA yet
I have a Nanovna, have used it to check my chokes but they are a different design. The screen of the Nanovna is small but you can get the data displayed on a PC.
@@g0fvt how did you setup your nanovna (connection whise) to test your chokes ?
Aleziss I used the VNA in two port mode, if you Google “g3txq choke” you will see a similar set up. I shorted the “input” wires to the choke and connected them to the RF output of the VNA and shorted the output leads of the choke and connected them to the other port of the VNA. In other words the choke is tested as a two terminal device. The sweep is then done plotting loss between the ports of the VNA.
A remarkable result, very impressive.
thank you for your comment ! I am still waiting to measure attenuation with a nanovna and it will confirm that this type of balun is really effective. As you saw, SWR is fine so I am pretty sure the attenuation work as it has been a proven method of doing common mode attenuation.
if you want to see the attenuation with a nanovna you can check my video here th-cam.com/video/k2DAyvciyow/w-d-xo.html thanks !
You have 1:1 balun connected to 50 Ohm dummy load. Why would you expect any SWR other that 1:1? The common-mode choke you have does not change SWR, it suppresses any reflected power going back from the dummy. Have you tested it without balun and saw different results?
@ikatkov I know what I did built is supposed to ATTENUATE (not suppress) common mode current. Now, how can I know what I did build would not change the impedance reading thus impact the SWR readings ?? what does tell me the random ptfe wire I have is the right impedance ? What does tell me the winding with the specific unknown wire I have is the right one ? It's not even the same size as suggested by trxbench, even Peter said that one type of wire he used did NOT work you can see that in one of his previous video... the only way I could at least get the impedance question out of the way was to test if the impedance was not affected by the core and winding and it seems not.
The right way to test common mode attenuation would be to use a vector network analyzer or a rf signal generator with a rf spectrum analyzer which I do not have. Do you have a way to test common mode attenuation ? If so tell me right away !!!
So how can I test a dipole and see how much common mode attenuation I get by installing the choke or not ? I can't "SEE" any of this ? I don't undestand what you are saying...
The characteristic impedance of a transmission line depends on the geometry of the conductors. The coaxial cable has a certain parallel capacitance an serial inductance per length that gives it it's impedance. If you insert a twisted wire pair as shown here, it will likely have a different characteristic impedance. You could use this to calculate www.allaboutcircuits.com/tools/twisted-pair-impedance-calculator/ . When there is an interruption in a transmission line due to a change in characteristic impedance, you will have reflection and therefore a non-zero SWR.
@@ramorrisey wow... this is adding to the worries I had in regard of the impedance of the wire and how it is winded...
So what I've done there might be totally wrong (or not too much since SWR seems quite ok besides 50mhz)... I did it this way to prevent wires being away from each other... the link you sent me requires quite a bit of measurement, lenght of wire, spacing between wires, how many twist, thickness of insulation... this is a bit out of my abilities, I would need a vernier, another tool I do not have... the maths are also quite crunchy, thank god for the online calculator !
So if I understand what you are saying, they "could" be twisted but would need to be identical on both sides, including lenght and twist OR I would need to leave all wires straight without twisting them and I might have better results ?
I just wish I had someone who could help me with a VNA...
Thanks for your comment !
The reason for 2 pairs of parallel conductors is to get close to the right characteristic impedance. At the lower end of the frequency range with relatively short conductors it will cause less of an anomally. TRX bench did test common mode impedance (as I have done with my ones), if you have used the correct core material you should be good to go.
@@g0fvt thanks for the comment. I did use the FT240-43 core as he suggested, a core I already had to make an end fed half wave antenna but decided to build that balun instead. It will be use on a 2 element 40, 20, 15, 12, 10 and 6m beam next year... as it is too cold to play in the tower right now ! As someone else mentionned in this post, twisting of the wires might not be a good idea so I will straighten these instead and keep them together with a shrink tubing.
You did a good job. I hope it fits your needs. Sure is a lot better than buying a balun.
Barry, KU3X
Hello Barry, thanks for your positive comment, I know that test was not really scientific but you can check my other video where you can see the actual common mode attenuation with a nanovna which is way way better than the actual balun that came with the antenna I use it on. th-cam.com/video/k2DAyvciyow/w-d-xo.html
I installed the antenna two weeks ago, a TGM Communication B-246 compact 2el beam that covers 40/20/17/15/10/6m and it works really well. Cut down all RFI I had previously in the shack too !!! You can see the antenna on my QRZ page.
73 de Claude VA2CST
Good results
Now that it's much too late for this test, there's the NanoVNA that would have been just right. Starting at around $50, it's an amazing tool. For most uses, though, connector adapters are also needed, which increases the total cost.
hi thank you for your suggestion, I indeed got the nanovna-h model but setting it up for measurements is not done easily and I get uneven results so I can't really test this properly at this time but I know this type of choke balun works really well. I'll have to make some more tests and try to make this work properly with the vna which is quite difficult not having the right adapters as you need to put resistors in the line... those nanovna's arent really precise tools...
by the way here is the NanoVNA attenuation test and it is excellent ! th-cam.com/video/k2DAyvciyow/w-d-xo.html
Well done.
thank you for your comment, it works really well, it's been installed on a small compact 2el yagi that covers 40/20/17/15/10/6m. I have made another video where you can see the common mode current attenuation and it is really efficient only with a single core.
The SWR doesn't tell you much about the quality of a balun: what you measure is the reflected power but you don't know how much goes out the other end and how much ends up in losses. Furthermore, the main task of a balun is to offer a balanced port (or vice versa) and this certainly does not prove to you a SWRmeter.
A VNA is not mandatory: to get an idea of the losses using a SWRmeter test the balun by holding the balanced port open and then shorting it. In those cases the SWR must be infinite: the power that is not reflected ends up in losses (check a table to convert SWR to dB).
Other method: make two identical balun, connect them to each other through the balanced port; with a wattmeter read the exact power of the tx and then read it again with the two baluns in the middle and connected to each other in that way. Divide the difference between the two measurements by two.
Finally, to verify that the balanced port is really balanced, I recommend my article on the balun-choke test: you can find the link on my QRZ page (sorry: it's in Italian. I hope Google translate can help you). 73s.
I understand all of what you are saying. My goal with the SWR testing is because I had unkown PTFE wire and I wanted to see if it would have a bad mismatch of impedance. I KNOW this is NOT the goal of a balun.
I have another video where I do test the common mode attenuation and it is really efficient and this mode of wiring is well documented for a proper choke.
Last thing I would need to check, as you mention, the efficiency of the balanced work such device provide. I will look into it.
If you read the video description, you will see where I got all the info from Peter's TRX Bench where he got all the info from Wolfgang DG0SG www.dg0sa.de/ now your turn, all in German. A LOT of information about baluns, chokes and measurements. Family graciouly left Wolfgang website up after he passed away.
73
I would recommend NOT tuning the VFO while the radio is keyed up. I did that with an ICOM IC-706MKIIG once and it smoked the finals. When I called ICOM and told them what happened they said never transmit while tuning the VFO. I had done it on other radios prior to that one and never had a problem. Just wanted to mention it.
thanks for the tip, as you seen though, I was at low power (10-15W) and when I ramped up the power to 100W, I did not move the vfo while transmitting. I too have a 706 and they are old radios with many of their parts being at their age limit, with the combinaison of all of this, it "might" happend but it is the first time I hear final get blown because moving a vfo while on tx. Maybe swr whent too high while you were moving around... I was with a dummy load... anyway, thank you for the tip and comment.
It could be a problem when the PA transitions from one bandpass filter to another, otherwise should not be an issue, anyone that used the earlier ham satellites with linear transponders will be familiar with using VFO while on transmit.
@@g0fvt I still use the linear transponder to this day !
Agree @g0fvt I tune mine up and down all the time, I think this guy had other issues lol
how much power one ft240-43 can withstand in this configuration
about 800W no problem, you can stack two if you need over 1.5kW
very hard to see the wiring with all white wire ...do you have a schematic? ....otherwise nice tutoral
go see the description and go check TRX Lab video, you'll have all the details if you cannot follow and pause the video, Peter explain everything you will need to know.
actually the design comes from DG0SA you can find here www.wolfgang-wippermann.de/balun1zu1gross.pdf pretty simple to build with PTFE wire.
Hi nice demo, can you share the link for the wire?
thank you for your appreciation. PTFE wire was similar to this one www.ebay.ca/itm/263758650100
What max. power are you using it? Can it handle 1kW with max swr 1:3?
I was doing short burst at 100W because my dummy load can only accept 15 watts... TRXbench states that it should handle 800-1000w and you can see that my radio does not register any SWR on HF bands at 100W. If you want more, you can stack two cores, it should handle easily 1.5kw
FWIW I have run significantly over 1kW through similar, I did wind one with PVC insulated wire, huge dielectric heating. Teflon insulated wire version did not heat significantly.
do you have a link for the teflon wire please? gr8 vid btw
@Ralph Kluge thank you for your comment, the wire I got was like this : www.ebay.ca/itm/263758650100 but I made an error ordering 16AWG instead of 18AWG... I just noticed also that it is rated at 300V and I think Peter said that for high power, it would be better with 1KV wire... this might not fit the build if you are using really high power... In my case, I will only run 100W...
I you are in the UK, you can order it from CPC: cpc.farnell.com/c/cable-leads-connectors/cable/cable-wire/hook-up-wire?jacket-material=ptfe
Also the Farnell group stock it. Just search their cable category and choose PTFE as the jacket material.
I am yet to see a video of one of these working against unwanted noise. I found a video of someone simulating noise being picked up on the coax but what if you have very bad powerline noise and the antenna is picking it up? Then i suppose a 1:1 balun will do nothing to help? Or will it? I have S9 of powerline noise right now and even when i turn off all the power to the house and use a battery. Neighbours are far away, it's defiantly dirty powerline noise, i have driven around with an AM rig in the car and it's this entire hillside and unfortunatly i live 200 yards away from the lines in question!
These are NOT to get rid of electrical noises, they are design to make a unbalanced line connect to a balanced antenna AND ATTENUATE common mode currents. I too have heavy electrical noises from hydro power, probably due to faulty isolator somewhere in the neighborhood and having a balun like this one change absolutely nothing for noise levels.
I get +20dB of noise on 40m, usually +15dB on 80m each winter it is the same situation and this year again, I can't make any radio specially during evenings and nights. Beleive me, if you are searching for a solution to get rid of electrical noise, this won't do it.
Get yourself a magnetic loop, those are immune to "electrical" noises as they pick up "magnetic" waves. Or if you have two HF antennas, you can get a Timewave ANC4 or a MFJ1026. Those are working ok but it requires two antennas to null electrical noises.
@@Aleziss I have decided that i am going to build an X-phase unit such as the MFJ one.
There is a Russian guy selling kits, boards and ready made units but also VK5TM in Australia sells his version of the boards and has a great explanation and instruction if you google him.
So do you use the X-Phaser to help with the noise?
Funny that yours is from Hydro as our Hydro station is only about 5 miles away or less as the crow flies. Why would hydro be particularly noisy? Perhaps it's a coincidence? I am going to look further into it as nowhere else except this village suffers from it this bad. The entire hillside here is stupidly noisy but not worse than S7 to +9. I am starting to order the parts i need now.
You don't necessarily need two full sized HF antennas. The noise is not really band specific, it is across the bands so it will tune in on any antenna. I might try an old TV Yagi as the aux antenna and point it at the power lines for the greatest source of noise.
I am also wondering what the possible health implications might be. There is great debate about health concerns of living under power lines but no info that i can find on how this could be an increased hazard if the lines are particularly noisy. The noise is particularly bad around this particular set of power lines on the hillside but i can also hear it from a mile or two away from the lines.
@@Aleziss regarding the choke not stopping noise. I would have thought it might help as it is designed to only let the matched signal pass and not let anything else back down the coax. Anyway thats why i was asking, thanks for clarifying that it does not help. 73's
@@izzzzzz6 well, what I meant by "hydro" is the service provider that is called "hydro quebec", the noise don't come really from hydro power generation method but rather faulty isolators or bad transformer. The difficult task is to find where the noise comes from, it could be right in my backyard or two streets away. I sent a complaint to "hydro quebec", they do have an RF truck with a bunch of antennas, spectrum analysers and they can pin point where a source of noise could come from with directional antennas and doppler... thing is I sent that complaint over 1 year ago and it is still not fixed, S9, S15 even S20 is not rare, usually when it is really cold and dry, noise levels are extremely high to the extent I cannot use the radio on 80, 40 and sometime 20m, impossible to make any contacts.
I do have a MFJ1026 but it does requires two antennas. Both antennas should pickup the same signals in order to successfully null noise. If one antenna is less effective and does not pickup what the main antenna is picking up, there won't be good result as you cannot invert and null out the noise level. This is really how it works. You can't have a full dipople as a main antenna and a small antenna as the second antenna, you won't have enough gain to pickup the noise if the second antenna is too small and is not desigh to pick the noise in the same frequency range.
Users that have multiple dipoles will have the best results with those noise cancelling units. It is not as simple it looks to be. I have not got good results with the MFJ1026 just for the fact that my second antenna is way less sensitive than my main hf antenna.
Good luck with the tv antenna, on my side I did try a vhf yagi as the second antenna but it did not work at all.
@@izzzzzz6 I am not sure you understand the balun correctly... the balun is used to take the unbalanced output of the radio coaxial and transform it into a balanced feed like a dipole, two equal side of wires that resonate at a particular frenquency. Any unbalancing on a dipole (for whatever reason like ice, a bird sitting on one side of the antenna, tree brannches closer to one side of the dipole than the other, and so on) will result on RF coming back on the outside of the coaxial cable, the skin effect, which is also called common mode currents. What comes back on the outside of a coaxial cable is generated by an improper balance antenna and come back as RF transmitted by your transceiver. The common mode choke will block those current on the outside of the coaxial cable at the antenna where the choke should be installed.
Now receiving electrical noises from electrical arcking due to faulty isolator, faulty transformer, faulty splice and so on, is picked up by the antenna itself, just as if it was a radio transmition from another station thus come in the center of the coaxial and not from the outside of the coaxial like common mode currents. Does that makes sense ?
Drop of power on 6m is due to the specific torroid choice
possible, still got 20dB+ of attenuation when I tested that choke with the nanovna, it does the job ok for my need... I think mix 52 is better for higher frequencies but to the detriment of lower frequency, the antenna I currently use run from 7 to 50 so no need for me to go below 7MHz so I might try one day with another core... but I paid 5$ for a single FT240-43 and now they are 15$ a piece... I should have bought much more back then, same goes with the other mix, price have sky rocketted over 2 years only since there is a lot of demand for those cores
@@Aleziss as we are not able to use the 6m band a lot anyhow😁
@@on2mvh937 yeah specially in my antenna, it is only a dipole for 6m so not much efficiency but there is a "big gun" station in my province that run a 6el 6m on a telescopic tower and he makes many contacts every day so I guess we are too cheap for 6m hihi !
Yes... two things- you will certainly need a vna or specan to see what the common mode measures. It should be greater than -20db down or as Peter would say “it’s not doing its job” checking the SWR is only secondary to the CMC measurement. I am also surprised you used the same colored wire? Would have made me crazy! I used the same colors that Peter used, Orange/Blue PTFE. My CM 1:1 Balun checks out great. I do have a VNA and a specan - where r u located?
Hello David, thanks for your comment, I am located in Quebec Canada. As for the color, I did not mind too much, I agree it would have been easier to sort everything out for sure but at the time, I had hard time finding the right wire as per Peter description, the only color I could get back then was white ! I have a nanovna but I can't make this work properly. I am not even able to measure a coax lenght and see it's resonance. The nanovna gives me crazy SWR on a coax lenght that has a 50ohm terminaison even though my MFJ and radio SWR reading sais otherwhise. I am not mastering this properly or I have a defective nanovna unfortunately...
Aleziss Dear Alexiss, I understand. I was able to purchase the blue and orange PTFE. Online. It’s been a while. First, make sure that you are using non inductive resistor load when checking SWR. But without checking the CMC first, it’s really a waste of time. As Peter mentions many times, the first job of the “Baloon!” (Peter) is the CMC then SWR. But you must have the equipment to do so. Do you have any friends close by who would have a VNA? I have a HP8711A RF Analyzer and a specAn but we’re not close. I am in Cleveland. I also bought one of those small $ 50 nanoVna. But it died within a week. So it’s in the junk box. Good luck to you.
@@davideisenberger6197 It seems I don't have the "GAIN" on the second connector on the nanovna, I am not sure why. The only measurement I found was "LOGMAG" but I am not sure it is the right measurement. I found the "GAIN" measurement on the external software (nanovna saver) but there are big difference in reading between the nanovna and what the program read... I don't have the right adapters for the nanovna so I have to order those parts too... probably from china which will take months to arrive...
@@davideisenberger6197 Hi David, I made a follow up video using a nanovna and it seems to be working pretty well while measuring the attenuation. You can see the results here : th-cam.com/video/k2DAyvciyow/w-d-xo.html of course this is far from having high precision measuring equipement but I think it gives a rough idea of the performance. Thanks for all the previous comments !
Is it wound round a magnet
no it is wound around a 2.4 inch ferrite core mix 43
What kind of common mode suppression are you getting?
I'm getting around -26 to -21dB from 1.8 to 54MHz
actually a lot better when I tested it with a nanovna you can see my test here th-cam.com/video/k2DAyvciyow/w-d-xo.html thanks !
So, checking for reflection with a purely resistive load? Any one see any issues with this?
look, I am experimenting, the only thing I can test at the moment is if thiw will cause an imbalance in the inductance or capacitance and change SWR. At this poing, it seems not to influance anything, it does not add any SWR and that was my test. If you have something to say so we can learn, please go ahead...