When I got my technician license I had a radio but no antenna. I ordered a "slim Jim" that is similar to this, but made of ladder line. Elevated to about 20 feet it worked great. Finally got a copper pipe j pole and stored the slim Jim. But! I have been using it in the shack on my UV5R for about a year, which I use to monitor the local repeater. I can hit that repeater using low power, and the antenna is inside where it is much less likely to get hit by lightening!
You might be interested in Ed Fong's dual band roll-up antenna made from 300 ohm twin lead. There is a good build and review article in the March 2007 QST titled "The DBJ-2: A Portable VHF-UHF Roll-Up J-pole Antenna for Public Service"
I've used one of these in the Boundary Waters ( Minnesota ) in areas where there is no cell phone coverage. Works great with a little elevation. It's a great camping accessory. I built mine in 1992. Love it!
I love the j-pole antenna! I've used them for many years and the never disappoint! BTW, I think the radio Shack HT202 is a great simple to use HT. I've had both the 202 and the 404 and I'm sorry I sold them! I don't use half of the features on my newer HT's (who uses 900 memory channels anyway?)
Hey Kevin, good to see you made it there safely. Pocket J-Pole, got one and have used it on ARES deploy for bike rides or 5K,10K, and marathons in the local area. I usually get placed at the far end from the start line and it has always reached in with no problems. I usually keep it at 5W but have pushed 25W with no apparent problems. Looking for your next video, keep 'em coming.
I have a backpack J pole for camping and a fairly large Comet GP-6 antenna for my solar powered base station but I think I'll make a few of these PVC pipe weatherized J poles for local friends who are getting into amateur radio for personal emergency communications, to save them some money. I love that I can avoid an exposed RF connector by using whatever length of coax is needed for each specific installation, and I can use whatever length of PVC I want to optimize performance versus aesthetics. I have some 1/8" NPT plastic pneumatic vent caps that I can easily use for a vent on the bottom cap of the antennas. Great idea to use those snap in broom handle clips for your temporary mobile RV mounting.
Thanks for the video. I made a dual band version one of these earlier this year...but I couldn't find twin lead, so I used regular wire and 3d printed spacers to make my own twin lead! A j-pole is basically an EFHW on 2M.
I'm just about to build something like this to go with my "new to me" FT818ND. Twin lead isn't easy to find but I might try a satellite "shotgun" twin cable and see how that does. Edit: Just found FM aerial twin lead, 300ohm cable. That looks like a good candidate. Thanks for the video Kevin.
Thank you Kevin. I'm glad you are set up in the desert where the environment agrees with you. I am going to build this J pole and hang it up here in my upstairs ham shack. I also have the old RatShack HTX 202 and it will be brought back to service with that antenna.
The author of the article suggests a ferrite bead on the coax to keep RF off the coax. I actually did this with my build, and found that I could fine-tune the SWR after I found the tap point by moving the bead away from the shorted stub. I built mine from 400 ohm window line because that's what I had on hand.
Really like the broom hanger idea. Probably will build one to keep in my travel trailer. Wonder if a quick coat hanger yagi would reach out and activate the Kingman repeater?
The twin lead J-pole is great for portability since it rolls up into a nice small package for transport. However, see my video on the slim jim made with window line. It's a much higher performance antenna if you're looking for a more permanent installation.
@@loughkb Hi yes I have also seen that one and looks amazing really looking forward to building one. Not working at the moment just to this covid. However as soon as I am back in employment I will be able to get the parts 🤞🏼. Keep up the great work and hope to talk on the air one day. Motters M7TRS 73's
New ham here so super great video, I wll bild one since I have an antennaless Ft-7100 on my radio desk and have only worked HF thus far. I want to get it going and make comparisons as I build bigger and more substantial antennas for it.
If you have a FM Ribbon radio antenna where the feed lead has torn off what about turning that into a J Pole Antenna and connect your coax to the ribbon cable about half way between the bottom and where the feed point was and should be used with a FM Broadcast Receiver, I hope that PVC pipe doesn't melt as it suspect that 144.0mhz might be at a harmonic of resonet frequency of the Chlorine atoms which is 27mhz.
Yo Kevin!: As usual GREAT video! At 1st I thought the broom holders were metal and would affect pattern/swr, but later in the video saw they were plastic. Gonna send an e-mail for update on how I'm doing.. 73's! Motor on guy! de seeker/Jeff WA7LFP
Found the problem. Had to reboot the modem. Re-booted router to be safe too. There are several DIY QST articles available; here are three, Jim Reynante, KD6GLF September 1994 pages 61 to 62, and Edison Fong, WB6QIN, February 2003 "The DBJ-1: A VHF=UHF Dual-Band J-Pole" pages 38 to 40 and March 2007 DBJ-2: "The DBJ-2: "A Portable VHF=UHF Roll-Up Dual-Band J-pole Antenna for Public Service" pages 38 to 40. KB8AMZ
I just passed my Technician license test yesterday and I need a 2 meter antenna for my Yaesu FT-4VR mono band 2 meter HT I got for free for passing the test. I am now waiting for my license and name appearing on the database. I have to go out on the deck to be able to hear the repeater and I want to be able to do this from the inside of my QTH. I wonder if you can make a J pole out of speaker zip cord. What kinda db gain do ya get on that antenna?
good to have you back in my home state kevin i'm gonna have to look into this gem build one myself. i hang on 145.410mhz & 447.725mhz i hope to catch you on air make contact hf 40 an 20mtrs 73' K7SCE
Great video, as always Kevin. One question though. The wire above the gap in your j-pole is not electrically connected to anything. Does it form part of the radiating section of the antenna? If so, then how? Thanks, David M7DKS
@@loughkb you are right, I saw the flat cable and thought of a slimjim without hesitation hehe. I wonder if leaving that 1/4 lambda strip would interfere with the radiation pattern..
Hi Kevin, I built a similar one a few years ago which was dual band 2m and 70cm. I tuned it with a spectrum analyser and got two bang on dips in the SWR. I then put it into a PVC pipe as you have done and found it shifted the centre frequencies. I had to retune the tap points for use in the pipe. I made the pipe about 30cm longer than the antenna and wrapped a sprip of red insulation tape where the antenna ended so that I could ensure the mounting hardware didn't go above the red tape and interfere. Fantastic antenna.
Its not visible in the photo, but I have a line drawn on the pipe where the antenna starts. I didn't see any shift in the tuning when I put it in the pipe. I wonder if the material is different than what yours was made of?
Kevin, I bought the Ed Fong dual version, recorded the swr in small MHz increments on both bands, then added a 3/4 in pvc tee for the so239 and a 9 in sch 40 full wall tube at the bottom of tee for mounting. Compared swr to previous record..works great up to about 15 - 20 watts before noticing a sharp rise near upper 2m at 1.75:1 and high near the low end of 70cm 2.0:1 but drops quickly as frequency rises or power in 70cm is below 10 watts. All useable. Copper jpole works like a charm..at 25 foot elevation and 50 watts from sw Warren to Flint brought up the 7.100 2m repeater with 7,7 report on that Kenwood you now have. 73, kb8qlz
Thumbs up! Always meaning to make a J-pole or Slim-Jim with this type of feeder. A thought, would a VHF and UHF version work okay though a diplexer with the appropriate wavelength separation distance into a dual band radio?
@@Jimwill01 I'm thinking a jpole cut for VHF plus another cut for UHF. Then, coax from each aerial into a diplexer and the output into a dual band radio :-)
@@loughkb The one I just made - 300 ohm twinlead inside of 1/2" PVC - was 'cut' for just a hair under 150 MHz. Once I put it inside the pipe, it tuned up perfectly on 146 MHz. I suspect the PVC also broadens the bandwidth somewhat, though I haven't done any comparisons to confirm that.
Having just purchased a 220 radio, I was wondering what the dimensions for a 220 Mhz Slim Jim would be? I am using a 1/4 wave ground plane I made, and while it transmits marginally, the reception however barely breaks squelch.
There's a few online calculators available. Search for slim jim calculator. Note, the slim jims are usually built with window line, not twinlead like this J-pole. (the slim jim is a different antenna than this one. I also have video on slim jims.)
Did the antenna change much when put into a pipe? I'd assume some kind of retuning would be required due to probable centeg frequency drop due to plastic.
Hello Michael, I have several, from magnetic loops to wire antennas. Presently I'm using an end fed half wave cut for 80 meters. It works really well through 20. I also have a 17 ft vertical end fed with a 9:1 and counterpoise wire. It's non-resonant, but gets me out on all bands from 14Mhz up through 6 meters pretty well with a tuner.
@@loughkb That would be do-able, it could be hanging from a horizontal pole poked out of the window. It would be easier to hang something from such an arrangement than to have it holding something propped up. But upside down would still be OK?
@@otakop67 Scanning other build pages and estimates are 10-20 is max. But I haven't found anyone that did any testing. Heat would be the concern though, at the bottom of the J. I don't have an I/R thermometer, but someone with one could test it. Pump in 10 watts and see if it warms. No, go up to 15, etc.
Kevin, I've been building several Slim Jims for HF frequencies (20m to 10m freq.) I copied the online calculators and ended up modifying some of the equations to fit my personal experiences. To me, the feed points seem to be a little off. The InterWeb calculators typically show a higher number (in feed point inches/or mm) than the final tweak.
Thanks for the kind words on my webpage. I'm glad it was useful. 73, Craig WB3GCK
It's very well done. I'm sure it has been helpful to viewers of this video as well. Thanks for producing it.
I built one years ago for my 2 meter handheld. Massive improvement over a ducky.
When I got my technician license I had a radio but no antenna. I ordered a "slim Jim" that is similar to this, but made of ladder line. Elevated to about 20 feet it worked great. Finally got a copper pipe j pole and stored the slim Jim. But! I have been using it in the shack on my UV5R for about a year, which I use to monitor the local repeater. I can hit that repeater using low power, and the antenna is inside where it is much less likely to get hit by lightening!
You might be interested in Ed Fong's dual band roll-up antenna made from 300 ohm twin lead. There is a good build and review article in the March 2007 QST titled "The DBJ-2: A Portable VHF-UHF Roll-Up
J-pole Antenna for Public Service"
I've used one of these in the Boundary Waters ( Minnesota ) in areas where there is no cell phone coverage. Works great with a little elevation. It's a great camping accessory.
I built mine in 1992. Love it!
I love the j-pole antenna! I've used them for many years and the never disappoint! BTW, I think the radio Shack HT202 is a great simple to use HT. I've had both the 202 and the 404 and I'm sorry I sold them! I don't use half of the features on my newer HT's (who uses 900 memory channels anyway?)
Good one Kevin, this will actually suit me right now as we have just moved so will build this. 73
Hi ! I've watched lots of vids for the 2m ladder line jpole & this is far the best I've seen so thanky 73
Hey Kevin, good to see you made it there safely. Pocket J-Pole, got one and have used it on ARES deploy for bike rides or 5K,10K, and marathons in the local area. I usually get placed at the far end from the start line and it has always reached in with no problems. I usually keep it at 5W but have pushed 25W with no apparent problems. Looking for your next video, keep 'em coming.
I have a backpack J pole for camping and a fairly large Comet GP-6 antenna for my solar powered base station but I think I'll make a few of these PVC pipe weatherized J poles for local friends who are getting into amateur radio for personal emergency communications, to save them some money. I love that I can avoid an exposed RF connector by using whatever length of coax is needed for each specific installation, and I can use whatever length of PVC I want to optimize performance versus aesthetics. I have some 1/8" NPT plastic pneumatic vent caps that I can easily use for a vent on the bottom cap of the antennas.
Great idea to use those snap in broom handle clips for your temporary mobile RV mounting.
Thanks for the video. I made a dual band version one of these earlier this year...but I couldn't find twin lead, so I used regular wire and 3d printed spacers to make my own twin lead! A j-pole is basically an EFHW on 2M.
Good video. These J-poles are handy for their portability. Thank you. This explained a tuning problem I had with a J-pole. N0QFT
I'm just about to build something like this to go with my "new to me" FT818ND. Twin lead isn't easy to find but I might try a satellite "shotgun" twin cable and see how that does.
Edit: Just found FM aerial twin lead, 300ohm cable. That looks like a good candidate. Thanks for the video Kevin.
This is an excellent project for new hams. Thanks for sharing.
Thank you Kevin. I'm glad you are set up in the desert where the environment agrees with you. I am going to build this J pole and hang it up here in my upstairs ham shack. I also have the old RatShack HTX 202 and it will be brought back to service with that antenna.
Great project.....I think will try one of these for a GMRS emergency portable antenna as well.
The author of the article suggests a ferrite bead on the coax to keep RF off the coax. I actually did this with my build, and found that I could fine-tune the SWR after I found the tap point by moving the bead away from the shorted stub. I built mine from 400 ohm window line because that's what I had on hand.
Really like the broom hanger idea. Probably will build one to keep in my travel trailer. Wonder if a quick coat hanger yagi would reach out and activate the Kingman repeater?
Great work Kevin. I plan on making one after I buy a NanoVNA.
Great chat with Callum on his stream.
Motters M7TRS 73's
The twin lead J-pole is great for portability since it rolls up into a nice small package for transport. However, see my video on the slim jim made with window line. It's a much higher performance antenna if you're looking for a more permanent installation.
@@loughkb Hi yes I have also seen that one and looks amazing really looking forward to building one. Not working at the moment just to this covid. However as soon as I am back in employment I will be able to get the parts 🤞🏼. Keep up the great work and hope to talk on the air one day.
Motters M7TRS 73's
New ham here so super great video, I wll bild one since I have an antennaless Ft-7100 on my radio desk and have only worked HF thus far. I want to get it going and make comparisons as I build bigger and more substantial antennas for it.
Thanks for the video. Foam 300 ohm twin lead is really tough to cut through without cutting the wire.
Using a sharp knife, gently shave the insulation away, a tiny bit at a time. Whittle your way through it.
Hey 14 thumbs up in three minutes. Pretty good pal!
“Meow”from D.theC. 👍🏻
Thanks Kevin! I just posted a link to this on our ham club mail list. 73
Thank you for the informative video sir! 73 de AC6GM!
Nice job Kevin, I enjoy your videos very much. 73
If you have a FM Ribbon radio antenna where the feed lead has torn off what about turning that into a J Pole Antenna and connect your coax to the ribbon cable about half way between the bottom and where the feed point was and should be used with a FM Broadcast Receiver, I hope that PVC pipe doesn't melt as it suspect that 144.0mhz might be at a harmonic of resonet frequency of the Chlorine atoms which is 27mhz.
Love the intro music! Keep up the great video's and safe travels!
Yo Kevin!:
As usual GREAT video! At 1st I thought the broom holders were metal and would affect pattern/swr, but later in the video saw they were plastic. Gonna send an e-mail for update on how I'm doing..
73's! Motor on guy!
de seeker/Jeff WA7LFP
The broom holders are metal. But the actuall antenna starts above the roof line and well above them.
Found the problem. Had to reboot the modem. Re-booted router to be safe too. There are several DIY QST articles available; here are three, Jim Reynante, KD6GLF September 1994 pages 61 to 62, and Edison Fong, WB6QIN, February 2003 "The DBJ-1: A VHF=UHF Dual-Band J-Pole" pages 38 to 40 and March 2007 DBJ-2: "The DBJ-2: "A Portable VHF=UHF Roll-Up Dual-Band J-pole Antenna for Public Service" pages 38 to 40. KB8AMZ
I just passed my Technician license test yesterday and I need a 2 meter antenna for my Yaesu FT-4VR mono band 2 meter HT I got for free for passing the test. I am now waiting for my license and name appearing on the database. I have to go out on the deck to be able to hear the repeater and I want to be able to do this from the inside of my QTH. I wonder if you can make a J pole out of speaker zip cord. What kinda db gain do ya get on that antenna?
Good one Kev, gotta knock one up soon 👍🏼
good to have you back in my home state kevin i'm gonna have to look into this gem build one myself.
i hang on 145.410mhz & 447.725mhz i hope to catch you on air make contact
hf 40 an 20mtrs
73' K7SCE
Great video, as always Kevin. One question though. The wire above the gap in your j-pole is not electrically connected to anything. Does it form part of the radiating section of the antenna? If so, then how? Thanks, David M7DKS
Actually, both ends of the line should be shorted and soldered
No, the antenna with the top shorted would be a slim jim and I think the dimensions are a little different.
As far as I can tell from many articles I've read, it is not an active part of the antenna. Just left there for convenience.
@@loughkb you are right, I saw the flat cable and thought of a slimjim without hesitation hehe. I wonder if leaving that 1/4 lambda strip would interfere with the radiation pattern..
Hi Kevin, I built a similar one a few years ago which was dual band 2m and 70cm. I tuned it with a spectrum analyser and got two bang on dips in the SWR. I then put it into a PVC pipe as you have done and found it shifted the centre frequencies. I had to retune the tap points for use in the pipe. I made the pipe about 30cm longer than the antenna and wrapped a sprip of red insulation tape where the antenna ended so that I could ensure the mounting hardware didn't go above the red tape and interfere. Fantastic antenna.
Its not visible in the photo, but I have a line drawn on the pipe where the antenna starts.
I didn't see any shift in the tuning when I put it in the pipe. I wonder if the material is different than what yours was made of?
Kevin,
I bought the Ed Fong dual version, recorded the swr in small MHz increments on both bands, then added a 3/4 in pvc tee for the so239 and a 9 in sch 40 full wall tube at the bottom of tee for mounting. Compared swr to previous record..works great up to about 15 - 20 watts before noticing a sharp rise near upper 2m at 1.75:1 and high near the low end of 70cm 2.0:1 but drops quickly as frequency rises or power in 70cm is below 10 watts. All useable. Copper jpole works like a charm..at 25 foot elevation and 50 watts from sw Warren to Flint brought up the 7.100 2m repeater with 7,7 report on that Kenwood you now have.
73, kb8qlz
Thumbs up! Always meaning to make a J-pole or Slim-Jim with this type of feeder.
A thought, would a VHF and UHF version work okay though a diplexer with the appropriate wavelength separation distance into a dual band radio?
You might be able to build a 6 meter j pole. But the lower frequency bands would require too much length to be practical, IMO.
@@Jimwill01
I'm thinking a jpole cut for VHF plus another cut for UHF. Then, coax from each aerial into a diplexer and the output into a dual band radio :-)
This design is reported to work on uhf as well. I've checked it and the SWR was fine with mine.
I saw quite a bit of detuning when enclosing my twinlead inside of PVC.
Yep, you just have to look at how far it detunes, and detune the antenna the other way so that when you put it in the PVC it's on
@@loughkb The one I just made - 300 ohm twinlead inside of 1/2" PVC - was 'cut' for just a hair under 150 MHz. Once I put it inside the pipe, it tuned up perfectly on 146 MHz. I suspect the PVC also broadens the bandwidth somewhat, though I haven't done any comparisons to confirm that.
hey Kevin, how do i calculate all the measurements so that i can have it working on 156.8Mhz marine VHF please?
There are several online J-pole calculators. Here you go.
www.hamuniverse.com/jpole.html
@@loughkb thankyou Kevin
I throw these up in 40 ft trees. They kick ass man. Way better than average jpole.
Having just purchased a 220 radio, I was wondering what the dimensions for a 220 Mhz Slim Jim would be? I am using a 1/4 wave ground plane I made, and while it transmits marginally, the reception however barely breaks squelch.
There's a few online calculators available. Search for slim jim calculator. Note, the slim jims are usually built with window line, not twinlead like this J-pole. (the slim jim is a different antenna than this one. I also have video on slim jims.)
Did the antenna change much when put into a pipe? I'd assume some kind of retuning would be required due to probable centeg frequency drop due to plastic.
No change at all.
@@loughkb That's a real supprise! Most other antenna types seem to change quite a bit. I need to try that out too!
Great video.... What type of HF antenna do you utilize?
Michael VA6XMB
Hello Michael, I have several, from magnetic loops to wire antennas. Presently I'm using an end fed half wave cut for 80 meters. It works really well through 20. I also have a 17 ft vertical end fed with a 9:1 and counterpoise wire. It's non-resonant, but gets me out on all bands from 14Mhz up through 6 meters pretty well with a tuner.
Anyone have a link for the non-foam filled? I can't any thats not. Thanks!
Would it matter if you hung the aerial upside down? From the window of a tall building for example, so the feed is at the top.
It would need to be away from the wall a bit.
@@loughkb That would be do-able, it could be hanging from a horizontal pole poked out of the window. It would be easier to hang something from such an arrangement than to have it holding something propped up. But upside down would still be OK?
@@xanataph It should work the same hanging down as mounted upright. So much better than a Rubber ducky that's for sure.
good stuff
Thanks Kevin. Would using Wireman 450 Ohm ladder line use the same dimensions to get the same results ?
No. But there are J-pole online calculators out there. I think you can punch in the electrical characteristics and it will spit out dimensions.
Any idea how many transmit watts can this antenna safely handle?
5 for certain. I've run 12 in the past with no issue.
@@loughkb Thanks for the fast reply! I've been looking for something like this to handle 25-50 watts for SOTA. Any thoughts?
@@otakop67 Scanning other build pages and estimates are 10-20 is max. But I haven't found anyone that did any testing. Heat would be the concern though, at the bottom of the J.
I don't have an I/R thermometer, but someone with one could test it. Pump in 10 watts and see if it warms. No, go up to 15, etc.
Enclosing the antenna inside the PVC will screw up your SWR. It is really hard to adjust for the velocity factor.
I saw almost no change. *almost*
Looks interesting! :D
Do you need a balun?
No. It provides a near 50 ohm impedance as is.
Thanks I like it
I'm curious if the swr changed with close proximity to the camper ?
No. But the actual antenna starts about 1 inch above the roof line. Just coax down the rest of the pipe.
Checkout android app Radio Garden..world broadcast
Kevin,
I've been building several Slim Jims for HF frequencies (20m to 10m freq.) I copied the online calculators and ended up modifying some of the equations to fit my personal experiences. To me, the feed points seem to be a little off. The InterWeb calculators typically show a higher number (in feed point inches/or mm) than the final tweak.