Arrow Antenna, J-Pole

[KC4RAF]

Bought the above mentioned antenna (model: OSJ 146/440) last week and finally got it up in the air this afternoon. I know there are some that don't like the J-Poles, so this is for those that do or are undecided.
It is built with all solid aluminum rods and mounting bracket. The bracket is angle aluminum and has all SS hardware.
I set the height to ~ 28 feet, put the analyzer on it and liked what I saw.
At this time, all I checked was the VSWR; which came out to:
144.0Mhz to 148.0Mhz at <1.2:1.
The bandwidth came in at:
140.3Mhz to 156.6Mhz at 1.5:1

At a later date I will change out the RG-8 for some new cable since I've had this coax for ~20 years.
The antenna came from GigaParts at a price of $54.00 excluding tax, shipping/handling.

Was able to hit all the repeaters in a 35-40 mile range, made several contacts that were ~25 miles simplex.
And gave it a rest, (the XYL calling supper time and then trip to town). Plan to see what I can do with it tomorrow.
BTW, this antenna is 2 meter and 70 cm. My analyzer doesn't do UHF darn it
For those that are curious or wanting a little more info, hope this helped you.

 

[insanity213]

I have the same antenna and its excellent on 2 meter. On 70cm its about as sensitive on receive as a quarter wave ground plane. Be careful TXing on 70cm. I had bad swr problems until I put a choke at the feed point. Maybe that's just my specimen but if I were you I'd get an swr meter or analyzer to verify your installation.

Sent from my Pixel XL using Tapatalk

 

[KC4RAF]

Thanks for the feedback 213. Yeah it works great on the 2 meter band; haven't tried the 70 cm yet, will a little later today.
The instruction sheet that came with mine recommended that I place a choke at the base of the antenna for 70 transmission. The choke they posted should be 4-6 turns, and approximately 4-6 inches in diameter. I built mine at 5 turns and about 5 inch dia.
My analyzer only goes up to the 2 meter range, and it tested beautifully with less 1.2:1. You just can't ask for a better reading. But I would have been satisfied if it had been 1.5:1 or a little higher.
Glad to see that you are happy with your J-Pole.
73

 

[bharvey2]

I use the same model although I built mine from the plans on their website. It's about 20ft in the air and fed with about 45ft of LMR400. I wasn't expecting much from it but I was pleasantly surprised. I have hills to the east of me so that direction has trouble but I can hit most repeaters and operate simplex within a 40-50 mile radius.

 

[KC4RAF]

That's what I did bharvey2, Built one about a year ago and really liked the reports back to me and the performance of the antenna overall. But that one was only for 2 meters, so I decided to get the Arrow that was dual band. And I am very happy with it.
Thanks for your feedback sir, much appreciate it.
73

 

[kg5umh]

I also built my own. On 2m I ended up with 1.1:1 and on UHF 1.5:1. Using it with an HT now and the antenna is attached to my fence, so only about 8 feet AGL. I can hit the local repeaters fine and do about 10 miles UHF simplex.
Do plan to move to the top of the house. That will put it about 22 AGL so I should talk and hear better.

I did find plans to make the SWR adjustable on these antennas, but it looks like a lathe or a very steady hand with a drill would be required.

 

[bharvey2]

That's what I did bharvey2, Built one about a year ago and really liked the reports back to me and the performance of the antenna overall. But that one was only for 2 meters, so I decided to get the Arrow that was dual band. And I am very happy with it.
Thanks for your feedback sir, much appreciate it.
73

You're quite welcome. J-Poles are far from perfect antennas and they can be finicky. I don't think you'd ever see one in a commercial or repeater environment. That said, if you're aware of their shortcomings and deal with them accordingly,they can work okay. As I said, I've used them for for 2m and 70cm simplex contacts and was really happy with the performance; best on 2m but still okay on 70cm. I was home on this past field day but still made many distant simplex contacts.

 

[SCPD]

Hey Guys, I was reading your comments on the J-Pole antennas and the "not in favor of" phrase is sort'a me.
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There is, as far as I am concerned, nothing wrong with the design. If they are built sturdy they'll preform well and last a long time. As an engineer, I have some reservations- not their design, but directed towards those that construct them.
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As pointed out, you'll not see them in commercial settings- they are "amateur antennas." And though J-Poles have a solid engineering basis, unfortunately those that try to construct them often are, for a polite'r term; Not good at carrying out their design. That, plus there are commercial designs that preform much better (but here comes the $$ factor.)
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"Mickey Mouse" construction-- is that too harsh a term?
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If a proper design is MM'd by enuff people, any antenna will get a bad reputation.... And I fear J-Poles fit that category. Personally, I have run some tests with this design* and have arrived at my own (secret ) gain figures. When trying to compare them to any published numbers on J-Poles, the range is all over the place. I know what the theoretical is supposed to be, but the hard actual numbers are quite different.
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The very last thing I want to do is come in here and disparage this antenna. Mechanically- I have reservations- but properly construct'd, weather proofed, mounted and tuned etc. they are fine for ham use.
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As one who 'plays' in this stuff everyday, I can't help utilizing this opportunity to direct this into a scientific, educational realm-- try them (J-Poles) out against, side-by-side, other antennas. Prove or disprove the neigh-sayers with your own numbers.... you might be surprised (pleased) by the results...
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Cheers!
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......................CF
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*I have access to quite an antenna test range(s), -- every once and awhile I'll model'd some designs based on the J-Pole.

 

[majoco]

Well said. I made my "Slim Jim" from the original article by Frank Judd in a "Practical Wireless" back in the 80's - it's a piece of 32mm waste pipe with solid aluminium elements either side and after a bit of experiment where I made the connections, it has now worked well for nearly thirty years. No need for chokes or ferrites on the coax, it's been variously mounted on wooden fence posts, TV antenna masts etc. and never put a foot wrong apart from the odd bit of annual maintenance.

What I find strange is that most of the J-pole designs I see are made from copper pipe which has an extension out of the lower part which gets hose-clipped to the mast, metal or otherwise. No - this is wrong. Here's a pic of proper j-poles - no lower extension. The original J-pole was designed to be towed behind a Zeppelin airship, hence no ground connection. The arm of the "J" is a matching stub to a half-wave vertical element, there is no need for a bit hanging out the bottom.

You can't complain if your J-pole doesn't work right if you don't build it right! The original artilcle for a "Slim Jim" is here...

"Out of Thin Air" by F.C.Judd, G2BCX, plus lots of qualifications, Assoc IPRE, A.Inst.E, FISTC, etc, etc...

AFAIK there has not been a proper design for a 2m/70cm J-pole, 2m - yes, 70cm - yes, but combined - no!

https://en.wikipedia.org/wiki/J-pole_antenna

 

[AK9R]

What I find strange is that most of the J-pole designs I see are made from copper pipe which has an extension out of the lower part which gets hose-clipped to the mast, metal or otherwise. No - this is wrong.

The extension is only for mechanically mounting a copper J-pole to a mast. I don't think it has anything to do with the antenna's performance.

Several years ago, we had trouble locally with a couple of 2m repeater jammers. One of the old farts on the repeater used to boast about how he had a big beam antenna and whenever the jammer appeared on frequency, the OF would key up and tell the listening audience that he was "swingin' the beam" to find the jammer. Of course, a single azimuth-only data point was all but useless to locate the interference. One of the smarter guys on the repeater used to mock the OF by talking about "swingin' his J-pole".

 

[lmrtek]

Always nice to hear an antenna works as advertised

Sounds like a keeper!

 

[bharvey2]

CF and majoco, I couldn't agree more. Adhering to design specs is a must and failing to do so is most likely the cause of user trouble with the J-Pole. It isn't very forgiving of "ad-lib" engineering.

 

[majoco]

The extension is only for mechanically mounting a copper J-pole to a mast. I don't think it has anything to do with the antenna's performance.

Like I said previously and bharvey2 agrees, any departure from the original is liable to compromise the performance and insults the intelligence of the designer. The adding of another copper pipe at the bottom of the J pole "only for mechanical mounting" adds another 1/4 wave (more or less) stub to the antenna. How can you say that this will not affect the performance?

 

[KC4RAF]

You guys are right about any deviation from the original design. When I built my first J, I found that you HAD to follow the specs.
Even the fact that the mast sticks up above the mounting bracket can cause problems.
I will say that Arrow did a really good job in their building of this J. All solid parts and stainless steel hardware added quality to it also.

 

[lmrtek]

The best commercially made j pole type antenna design i recall was the Butternut super trombone antenna

It was built strong and had great gain

Its a shame Butternut quit making them

 

[wb6uqa]

6 meter j pole

There is a company selling a 6-meter pole. It is big.

 

[prcguy]

The Butternut super trombone is not a J-pole type, it appears to be a stub colinear or something else.
prcguy

The best commercially made j pole type antenna design i recall was the Butternut super trombone antenna

It was built strong and had great gain

Its a shame Butternut quit making them

 

[Golay]

Go long

There is a company selling a 6-meter pole. It is big.

About 10 years ago now, there was a guy selling homemade 10 meter J-poles at the Findlay Ohio swap.
Seems everyone that thought about buying one passed on it thinking "So how am I gonna get it home?".

 

[bharvey2]

Like I said previously and bharvey2 agrees, any departure from the original is liable to compromise the performance and insults the intelligence of the designer. The adding of another copper pipe at the bottom of the J pole "only for mechanical mounting" adds another 1/4 wave (more or less) stub to the antenna. How can you say that this will not affect the performance?

I've never understood how this could be justified either. Soldering on that lower mounting stub and then clamping it to a metal mast? Seem's you'd really hose yourself doing so. That's what I liked about the Arrow design assuming a non conductive mast is used.

 

[bharvey2]

About 10 years ago now, there was a guy selling homemade 10 meter J-poles at the Findlay Ohio swap.
Seems everyone that thought about buying one passed on it thinking "So how am I gonna get it home?".

I've seen designs for those too. Boy are they long. I guess if they were manufactured a bit longer than needed you could drag it home and hope you don't wear too much off the end