Here is a step by step build of the Open Stub J-Pole Antenna. Instructions can be found on NT1K.com or you can purchase these antennas at arrowantennas.com
A tip for making measuring and marking metal easier: take some blue painters tape and put tape down in the area you will be marking the metal. Now you can use a ball point pen to mark where you are going to drill. When done drilling you can remove tape.
Thanks for the specs on the antenna, I have made 3 of them now and they work great! I do find threading the rods to be the most difficult part. Something I do a little different is to cut the threads before cutting the rod to length, that way if I mess up the threads I just cut them off and start again without wasting the stock. Thanks for the video!
hoshnasi I bought them from Grainger. Luckily I have one pretty close. Home Depot Pro carries them up to 4 feet. Unfortunately that is a little too short for the longest element.
I used my Dowl-It jig (www.dowl-it.com/2) as a die clamp and chaser. I chucked the rod into my cordless drill and it cut the threads extremely straight.
Nice I legit just made 2 of of these and one 220 version. I'm lucky enough that I work in a machine shop so I chucked up the aluminum bar stock in the CNC lathes and cut the threads. Swr on 2m is flat under 1.13 and 70cm 1.3 or less The 220mhz ver is 1.2 I don't know how well the radiation pattern is on these kinds of antennas but they seem to work okay.
like it good job, sounds like u have worked in fabrication shop same as I was life time of work there... gr8 job keep it up injoying them. I'm jest starting into ham later man!!!
Can you adjust the SWR by threading the non-driven elements father up the aluminum so you could slide those up and down though the angled piece of aluminum?
@ 9:00 into the video. You'll see that the SO-239 comes with a plastic shoulder washer that insulates the "ground" with the center conductor. Confirmed with multi-meter. There is no dead-short.
Great video I’m going to make one out of 1/2 Cooper just a thought though when measuring the element wouldn’t you measure the length plus the thread as that’s going to be beneath the bracket 🤔 so in effect the element would be slightly short
I think this is all about the velocity factor of various metals. BTW some length correction would probably be needed for copper construction, as I assume there would be a slight difference. It seems to me, the thread length is probably already calculated in the overall element lengths.
Hello. How will the characteristics change if my aluminum corner turned out to be mirrored: the power cable on the right. All elements are of the correct length.
I like the Design, I was trying to look at the design plans on your website but they are to small and distort when I try to enlarge to read. The Link is no longer active. Do you know any way to view them so I can get a better look at them? thanks in advance
What about grounding (earthing) this antenna when it has been put up? I sometimes read a J-Pole does not need to be grounded while other people say the opposite. Can you tell me which is true in case of this antenna, please? Looks really lovely BTW. Thanks and 73.
Since your answers were ~ 50/50, I would say that only personal experimentation will give you the answer you seek. I'm betting though, their observations were probably related more to the fact they either had an "air choke"or not at the feed point, as this can wildly affect SWR / responsiveness at times on many DIY antennas. Adding the air choke, plus grounding can usually solve a lot of problems. Observe which one works better (with / without a ground), and mount accordingly.
Good work on the video. One question: The measured lengths of the reflectors have been functionally shortened by 'one nuts' worth of length. Should the measured and cut length be longer by that 'one nut' length that is lost below the aluminum angle?
The video goes alongside a blog article. The "element" dimensions are taken from the angle. So if you are using different nuts, you would have to change dimensions. If anything, cut long and adjust as needed. The antenna is wide banded (on VHF at least) and is very forgiving.
Great video. You have inspired me to purchase all of the materials to build one. Just curious... why not use 3/8"-24 on all three elements? Also, where did you find the PEM nuts?
** UPDATE 08/05/19 ** I've built 4 of these for mountain top relays (dual Baofeng set ups) and can attest that they work beautifully and are very forgiving. If you see these on eBay, buy them!
jbail or anyone, can you give details of the SO-239 connector being used? I can't seem to find one like this anywhere. It looks to be specific to this application. Any info?
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A tip for making measuring and marking metal easier: take some blue painters tape and put tape down in the area you will be marking the metal. Now you can use a ball point pen to mark where you are going to drill. When done drilling you can remove tape.
Thanks for the specs on the antenna, I have made 3 of them now and they work great! I do find threading the rods to be the most difficult part. Something I do a little different is to cut the threads before cutting the rod to length, that way if I mess up the threads I just cut them off and start again without wasting the stock. Thanks for the video!
Mike K Where do you go to buy the rods?
hoshnasi I bought them from Grainger. Luckily I have one pretty close. Home Depot Pro carries them up to 4 feet. Unfortunately that is a little too short for the longest element.
Mike K Thanks for the quick reply. I was concerned about pre-cut lengths.
I suppose you could always use a long threaded nut in the middle and make it a 2 piece.
I used my Dowl-It jig (www.dowl-it.com/2) as a die clamp and chaser. I chucked the rod into my cordless drill and it cut the threads extremely straight.
Hello, very nice job, congratulations from FRANCE
Nice I legit just made 2 of of these and one 220 version.
I'm lucky enough that I work in a machine shop so I chucked up the aluminum bar stock in the CNC lathes and cut the threads.
Swr on 2m is flat under 1.13 and 70cm 1.3 or less
The 220mhz ver is 1.2
I don't know how well the radiation pattern is on these kinds of antennas but they seem to work okay.
I Have built similar version of this antenna like (70 of them) the threads on the 3/8 24 need to to be sealed with silicon sealer.
Good video.
You have made plenty of them so I would ask, how do you like them compared to the 14ga romex inside a thin-wall pvc tube j-pole dyi design? Thanks
Use a lock washer on the underside .
like it good job, sounds like u have worked in fabrication shop same as I was life time of work there... gr8 job keep it up injoying them. I'm jest starting into ham later man!!!
Can you adjust the SWR by threading the non-driven elements father up the aluminum so you could slide those up and down though the angled piece of aluminum?
where did you get that SO239? it is different from those being sold, was it fabricated only
You just made a dead short Recheck it on the SO239 !!!
@ 9:00 into the video. You'll see that the SO-239 comes with a plastic shoulder washer that insulates the "ground" with the center conductor. Confirmed with multi-meter. There is no dead-short.
@@nt1k RR did not know that I never used that kind Thanks for the Info.
Great video I’m going to make one out of 1/2 Cooper just a thought though when measuring the element wouldn’t you measure the length plus the thread as that’s going to be beneath the bracket 🤔 so in effect the element would be slightly short
I think this is all about the velocity factor of various metals. BTW some length correction would probably be needed for copper construction, as I assume there would be a slight difference. It seems to me, the thread length is probably already calculated in the overall element lengths.
I know this is an old video, but could you use Brass rod? I have a good source for 3/8 inch thick brass rod stock.
Is there a calculator to make the elements for difference bands. Thanks
Hello. How will the characteristics change if my aluminum corner turned out to be mirrored: the power cable on the right. All elements are of the correct length.
So does it work ?
I like the Design, I was trying to look at the design plans on your website but they are to small and distort when I try to enlarge to read. The Link is no longer active. Do you know any way to view them so I can get a better look at them? thanks in advance
Will using a larger vise impact the SWR?😄
I can't get my die started to save my life
why not to shows the swr after finishing to assembly ??? this is important .
Can the longer driven element be cut into thirds and coupling nuts used to make it more portable? If so, would that impact the SWR?
Yes, no.
What about grounding (earthing) this antenna when it has been put up? I sometimes read a J-Pole does not need to be grounded while other people say the opposite.
Can you tell me which is true in case of this antenna, please?
Looks really lovely BTW.
Thanks and 73.
Since your answers were ~ 50/50, I would say that only personal experimentation will give you the answer you seek. I'm betting though, their observations were probably related more to the fact they either had an "air choke"or not at the feed point, as this can wildly affect SWR / responsiveness at times on many DIY antennas. Adding the air choke, plus grounding can usually solve a lot of problems. Observe which one works better (with / without a ground), and mount accordingly.
Does this perform half wave in both bands?
What is the SWR on this antenna ?
Good work on the video. One question: The measured lengths of the reflectors have been functionally shortened by 'one nuts' worth of length. Should the measured and cut length be longer by that 'one nut' length that is lost below the aluminum angle?
The video goes alongside a blog article. The "element" dimensions are taken from the angle. So if you are using different nuts, you would have to change dimensions. If anything, cut long and adjust as needed. The antenna is wide banded (on VHF at least) and is very forgiving.
very-Like!
Hell, what size of tap do you use in threading elements. TiA
3/8-24" thread die
Great video. You have inspired me to purchase all of the materials to build one. Just curious... why not use 3/8"-24 on all three elements? Also, where did you find the PEM nuts?
** UPDATE 08/05/19 ** I've built 4 of these for mountain top relays (dual Baofeng set ups) and can attest that they work beautifully and are very forgiving. If you see these on eBay, buy them!
jbail or anyone, can you give details of the SO-239 connector being used? I can't seem to find one like this anywhere. It looks to be specific to this application. Any info?
It's commonly used with CB operators. It's known as a SO-239 to threaded adapter. SO-239 to 3/8
Any good truck stop that sell CB' S will carry them.
Funny how all north american vehicles have all metric parts 🤔
Not Harley.
Good video! You might like the videos on my channel, I'm also planning some antenna videos. 73s de VU3TTL
Waste of time to many talk.there a lot nice vdeo rather than