Good video and solutions can be simple but sometimes hard to figure out. Even loose PL-259/SO-239 (whatever) connectors you may use, where ever the connection/joints occur, can cause RF in the shack from a poor coax shield connection so I cinch down my connectors a bit with plyers - just a bit tighter than finger tight. Also, good ground connections on pretty much every piece of equipment. One way to make a good ground is to connect all ground wires to a metal (aluminum) plate - say 18" square, for example, and lay that on tile of a concrete foundation floor - that makes a capacitor to the floor/Earth then run a good size wire to a water pipe, if you can, or a ground rod close by. Especially ground transmitters and tuners and always use a balun or coax choke (ugly balun) right at the antenna to help prevent radiation from the feed line. Of course, you may have your own solutions that work perfectly well and ferrite chokes can be part of a good solution. Thanks for the video. 73 WA4QGA
My ground is too an 8 ft. Copper rod outside the shack. But it doesn’t prevent common-mode current. There was still a bit of RF on the shield even after the 4:1 combi Balun. The snap-on chokes did the trick. Two made the difference but I ended up snapping a third on, just as insurance.
Thanks for all your videos! Your series on the FTdx10 caused my wallet to bite me haha. I won though and got it installed in the shack last night.....awesome radio! My desk shelves were too small and having the radio to the left and about two feet up wasn't working. So I places it dead center and put my monitor on top of the radio. (covered the speaker but thats why I bought the SP-30 too) And of course when I keyed up the RF caused my monitor to go into the settings menu. Ferrites to the rescue. Doughnut on the coax and the monitor cable solved that for now. I'll dig deeper after I watch all 3Gazillion videos you put out on the radio.
I find a type 31 or 43 1:1 choke on the OCFD feed before the coax enters the shack removes all the stray RF, in case it’s affecting other items of equipment 👍🏻
thanks for your video Doug. that's why I wont run a Ocv there known for rf problems . I was causing the lady across the street her garage door to go up and down and the older gentle men across from me his lamp to turn off and on. got rid of the ocf and problem solved lol. It also helps if one of the legs is Not going across your Roof
I’m fortunate that the only thing I interfere with is my westher monitor station. But it only happens on 30 meters. The chokes eliminated the issues with all the other bands. But, the OCF dipole doesn’t usually outperform my ZS6BKW or my doublet anyway. 73, Doug
Hi Jay! Chokes have gotten expensive, that’s for sure. I use the Palomar chokes. You can buy a box of them for $50 from HRO. I use Mix 31 for HF applications. www.hamradio.com/detail.cfm?pid=H0-016457 73, Doug
Those are from Palomar Engineers, but I purchased them from Ham Radio Outlet. HRO had a better price than ordering directly from Palomar Engineers. They make different sizes for different size coax. I think they might also have a combo box. Be sure to order the proper mix for your frequency range. 73, de N4HNH
Ladder line is designed to work as a balanced line. If it has any conductors nearby (wiring, pipes, steel siding, other antennas) it will become unbalanced and become a radiating system. Your attempt to attenuate the rf radiation from this feedline in the shack cannot work. The ferrite will only further unbalance the feedline. The best thing with balanced feedline is to send it out the wall, away from any interfering objects, right from the back of the tuner. This is how it was used years ago. And with tube equipment, it was far less vulnerable to interference from local RF. I proved it by all the lip burns I got using my Heathkit gear and a shiny D-104 microphone. A layman's way of analyzing your situation. Forgive me if I don't understand what is happening in your shack. You will fight RF constantly with that configuration. The best one can do to keep RF away is to feed with coax and convert to balanced line with a remote tuner or transformer once outside in free space. Always enjoy your videos. Thanks and 73... Mike
Hi Mike! The balanced line goes straight to the back of the tuner. The 4:1 balun is inside the tuner. I would rather choke the RF in the shack than drill another hole in my house to take coax out to a balun/tuner outside. That is a much more expensive solution than chokes. But the doublet is not the problem. Those chokes help it achieve a 2:1 or less SWR from 14 through 18.168 MHz with the tuner in bypass mode. I used a similar method, plus coiling the coax, to expand the resonance of the OCF dipole such that it stays under a 2:1 SWR from 3.5 to 4 MHz. If you watch the video again closely, you will notice that I did not blame the doublet for RF feedback. It’s the OCF dipole, with RF riding the shield back to the shack. But that only happens on bands that aren’t harmonically resonant. And I mostly use the ZS6BKW and doublet. They are consistently my best antennas.
@N4HNH Radio hello. Should I put the RF Choke on the Mic Cord Close to the Mic, Or Should I Put the RF Choke on Mic Cord were the Mic Cord Plug's into the Radio. Thank You.
Sorry, I don’t get into winding chokes. There are plenty of channels dedicated to that. Check out Dave Castler, KE0OG, and Jim Heath, W6LG. My main focus is operating techniques. Dave and Jim get into more detail with feed-line, chokes, antennas, etc. I have covered the use of chokes and locating the root cause of local RFI ad nauseam. I guess you somehow missed those videos.
There are 3 license levels in the USA. The first is Technician Class. The Technician Class license allows you to use FM repeaters, plus you can use SSB at up to 200W power output between 28.3 and 28.5 MHz. The exam has 35 questions. The next license level is General Class and the highest level is Extra Class. The General and Extra Class licenses allow expanded operating privileges on other HF bands, at up to 1,500 watts. You can study for the exams at: hamstudy.org/ You can contact the ARRL to find out where to take the exam. Or contact a local ham radio club. 73, de N4HNH
@@n4hnhradio Thanks Doug - distortion sounding like you are off frequency or white noise? Also, is it possible to get so much that it permanently damages your equipment?
It can cause damage if the amount is enough. I blew up the CAT port on my FTdx5000 because there were no RF chokes on the cable from RT Systems. The latest cables I’ve seen from them have chokes. The sound of RF in your audio could be described as sounding garbled or even robotic.
I bought a box of various sizes from Palomar Engineering. Get Mix 31. Avoid MFJ. They are garbage. I bought a bag of MFJ chokes and several of them were broken. They don’t seem to perform as well as the Palomar chokes.
Good video and solutions can be simple but sometimes hard to figure out. Even loose PL-259/SO-239 (whatever) connectors you may use, where ever the connection/joints occur, can cause RF in the shack from a poor coax shield connection so I cinch down my connectors a bit with plyers - just a bit tighter than finger tight. Also, good ground connections on pretty much every piece of equipment. One way to make a good ground is to connect all ground wires to a metal (aluminum) plate - say 18" square, for example, and lay that on tile of a concrete foundation floor - that makes a capacitor to the floor/Earth then run a good size wire to a water pipe, if you can, or a ground rod close by. Especially ground transmitters and tuners and always use a balun or coax choke (ugly balun) right at the antenna to help prevent radiation from the feed line. Of course, you may have your own solutions that work perfectly well and ferrite chokes can be part of a good solution. Thanks for the video. 73 WA4QGA
My ground is too an 8 ft. Copper rod outside the shack. But it doesn’t prevent common-mode current. There was still a bit of RF on the shield even after the 4:1 combi Balun. The snap-on chokes did the trick. Two made the difference but I ended up snapping a third on, just as insurance.
Thanks for all your videos! Your series on the FTdx10 caused my wallet to bite me haha. I won though and got it installed in the shack last night.....awesome radio! My desk shelves were too small and having the radio to the left and about two feet up wasn't working. So I places it dead center and put my monitor on top of the radio. (covered the speaker but thats why I bought the SP-30 too) And of course when I keyed up the RF caused my monitor to go into the settings menu. Ferrites to the rescue. Doughnut on the coax and the monitor cable solved that for now. I'll dig deeper after I watch all 3Gazillion videos you put out on the radio.
I can relate. I had to rearrange my shack to fit the FTdx10. Maybe you saw this video?
th-cam.com/video/puourYBqBbo/w-d-xo.html
73, de N4HNH
I find a type 31 or 43 1:1 choke on the OCFD feed before the coax enters the shack removes all the stray RF, in case it’s affecting other items of equipment 👍🏻
I have chokes outside on the coax. But at 1kW the RF still gets into the shack.
73, de N4HNH
thanks for your video Doug. that's why I wont run a Ocv there known for rf problems . I was causing the lady across the street her garage door to go up and down and the older gentle men across from me his lamp to turn off and on. got rid of the ocf and problem solved lol. It also helps if one of the legs is Not going across your Roof
I’m fortunate that the only thing I interfere with is my westher monitor station. But it only happens on 30 meters. The chokes eliminated the issues with all the other bands. But, the OCF dipole doesn’t usually outperform my ZS6BKW or my doublet anyway.
73, Doug
@@n4hnhradio the chokes work great wade N5bwp a big patron of yours and dear friend of mine got me some for Christmas I use them on everything
Hi Jay! Chokes have gotten expensive, that’s for sure. I use the Palomar chokes. You can buy a box of them for $50 from HRO. I use Mix 31 for HF applications.
www.hamradio.com/detail.cfm?pid=H0-016457
73, Doug
Sir, just came across your video, wondering where you got those or can order those chokes at? Any particular ones ?
thanks
Those are from Palomar Engineers, but I purchased them from Ham Radio Outlet. HRO had a better price than ordering directly from Palomar Engineers. They make different sizes for different size coax. I think they might also have a combo box. Be sure to order the proper mix for your frequency range.
73, de N4HNH
Ladder line is designed to work as a balanced line. If it has any conductors nearby (wiring, pipes, steel siding, other antennas) it will become unbalanced and become a radiating system. Your attempt to attenuate the rf radiation from this feedline in the shack cannot work. The ferrite will only further unbalance the feedline. The best thing with balanced feedline is to send it out the wall, away from any interfering objects, right from the back of the tuner. This is how it was used years ago. And with tube equipment, it was far less vulnerable to interference from local RF. I proved it by all the lip burns I got using my Heathkit gear and a shiny D-104 microphone.
A layman's way of analyzing your situation. Forgive me if I don't understand what is happening in your shack. You will fight RF constantly with that configuration. The best one can do to keep RF away is to feed with coax and convert to balanced line with a remote tuner or transformer once outside in free space.
Always enjoy your videos. Thanks and 73... Mike
Hi Mike! The balanced line goes straight to the back of the tuner. The 4:1 balun is inside the tuner. I would rather choke the RF in the shack than drill another hole in my house to take coax out to a balun/tuner outside. That is a much more expensive solution than chokes. But the doublet is not the problem. Those chokes help it achieve a 2:1 or less SWR from 14 through 18.168 MHz with the tuner in bypass mode.
I used a similar method, plus coiling the coax, to expand the resonance of the OCF dipole such that it stays under a 2:1 SWR from 3.5 to 4 MHz.
If you watch the video again closely, you will notice that I did not blame the doublet for RF feedback. It’s the OCF dipole, with RF riding the shield back to the shack. But that only happens on bands that aren’t harmonically resonant. And I mostly use the ZS6BKW and doublet. They are consistently my best antennas.
@N4HNH Radio hello. Should I put the RF Choke on the Mic Cord Close to the Mic, Or Should I Put the RF Choke on Mic Cord were the Mic Cord Plug's into the Radio. Thank You.
It usually works best to install the RF choke(s) on the radio end of the mic cable. However, sometimes, you might need them on both ends.
73, de N4HNH
Good video but a more extensive video on lowering RF in the shack would be more helpful. Constructing a rf PVC choke or alternatives would be great.
Sorry, I don’t get into winding chokes. There are plenty of channels dedicated to that. Check out Dave Castler, KE0OG, and Jim Heath, W6LG. My main focus is operating techniques. Dave and Jim get into more detail with feed-line, chokes, antennas, etc.
I have covered the use of chokes and locating the root cause of local RFI ad nauseam. I guess you somehow missed those videos.
Here's some feedback... thanks for these, you continue to fill in my knowledge voids. 73 de KD2TJU
Thank you Todd!
WHAT MUST I DO TO CHANGE FROM CB RADIO TO HAM,S
There are 3 license levels in the USA. The first is Technician Class. The Technician Class license allows you to use FM repeaters, plus you can use SSB at up to 200W power output between 28.3 and 28.5 MHz. The exam has 35 questions.
The next license level is General Class and the highest level is Extra Class. The General and Extra Class licenses allow expanded operating privileges on other HF bands, at up to 1,500 watts.
You can study for the exams at: hamstudy.org/
You can contact the ARRL to find out where to take the exam. Or contact a local ham radio club.
73, de N4HNH
What does rf sound like?
It will manifest as distortion in your transmit audio.
@@n4hnhradio Thanks Doug - distortion sounding like you are off frequency or white noise? Also, is it possible to get so much that it permanently damages your equipment?
It can cause damage if the amount is enough. I blew up the CAT port on my FTdx5000 because there were no RF chokes on the cable from RT Systems. The latest cables I’ve seen from them have chokes. The sound of RF in your audio could be described as sounding garbled or even robotic.
Thanks Doug! I need to add some chokes!
I bought a box of various sizes from Palomar Engineering. Get Mix 31. Avoid MFJ. They are garbage. I bought a bag of MFJ chokes and several of them were broken. They don’t seem to perform as well as the Palomar chokes.