Could someone out there explain if J pole antennas are worth the money I see them for online? Do they receive signals well when tuned to specific frequencies. Are they worth the money or there is better antennas for the same money?
J Pole antennas
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prcguy
Member
My personal opinion is to avoid them. A J-pole is a half wave end fed but its 3/4 wavelength long due to the 1/4 wave matching section. They are known to couple RF to the mast and feedline and they are pricey for the performance since a 1/2 wave center fed dipole that costs less than $1 to make will work about the same without the problems.
Thanks for that info prcguy. I saw a thread that had people raving about them. There can’t be much to them. I saw one made with copper tubing.
nd5y
Member
A lot of that is people who don't know much about antennas and/or who have never used anything else.
Ever notice how you never see J-poles (or Slim-Jims) in commercial or public safety use?
Ever notice how the major non-amateur antenna manufacturers like Commscope, Comprod, dbSpectra, Sinclair, Telewave, etc. don't make or sell J-poles (or Slim-Jims)?
prcguy
Member
If you take 10 people and give them instructions on making a 1/4 wave ground plane, the will usually all come out working about the same. If you take the same 10 people and have them make J-poles you will get at least 5 different levels of performance.
I have built a few, they work, but hard to get adjusted for match and without radials or counterpoise, you get stray RF on the feed and mast if long enough.
Companies that make them are overpriced, but a few hams make and sell them for acceptable price.
You can still make your own (knowing the math and what you are doing) cheaper yet.
My 6 meter J-pole I scrapped but only had $38 invested.
Get your hands on ARRLs antenna book, in there you can find better designs that give more bang for the buck.
73s
Companies that make them are overpriced, but a few hams make and sell them for acceptable price.
You can still make your own (knowing the math and what you are doing) cheaper yet.
My 6 meter J-pole I scrapped but only had $38 invested.
Get your hands on ARRLs antenna book, in there you can find better designs that give more bang for the buck.
73s
It’s funny you mentioned ARRL. I do have that book that I bought off a ham operator selling out and going south. Good advice, I’ll dig it out. I do however, enjoy reading all of your inputs associated with your years of experience!
I have used a cooper j-pole for years very happy with them
I have never been disappointed when following the advice of prcguy over others that post on this forum, or share information elsewhere. That is because I research his input/advice and learn even more along the way.
My experience with copper cactus j-poles has been very good. I had 2 meter, 222 MHz, and 440 MHz versions, all home built. I also have 2 portables made of TV twin lead that I used in simulated emergency events with good results.
Yes, those antenna makers sell great quality inventory along with a hefty price tag. I'm only listening, so at least I don't have to have the beefier antennas. Transmitting is a whole different ball game bringing high wattage rigs into play.
techman210
Member
And when you get to Ringo Rangers-
“keep moving, nothing to see here“
The more ridiculous the name, the worse the antenna.
“keep moving, nothing to see here“
The more ridiculous the name, the worse the antenna.
prcguy
Member
I would appreciate you researching my advice and letting me know if its good before I post it!
I have built a few but I build them for RX and they never let me down. I pick up signals 80 miles away with some distortion. I have one for air band and another for public safety. You can build one for about 20 bucks if you have all the tools. PRCGUY knows what’s up too.
I'm too lazy. Also, you correct the rare error when it occurs.
I own the KB9VBR Slim Jim, which is basically two j-poles on top of each other, and I love it. I use it for receive only in an apartment and works great. YMMV
N6JPA
A Ham Radio Operator With too much frequency.
A J-POLE Antenna is fine for a radio transceiver (amateur radio) and it is mounted in a clearing like a roof top. For a scanner radio unless you are doing long distance monitoring a simple 19 inch antenna with four radials will do fine for monitoring local systems. If you are monitoring simulcast trunked radio systems then you need a Uniden SDS-100 or SDS-200 radio scanner. YMMV. IMHO.
paulears
Member
When I got my licence all the older locals had slim Jim’s, because the inventor was a member of the early morning net that was a bit er, cliquey. He told everyone how wonderful they are, and easy to make. In fairness, our county is very flat and the lower radiation angle means they actually work better than a dipole here. He lived twenty miles away, had one on his bungalow, and could easily work all the net members. That distance on a dipole was just a bit too far.
I actually got a commercial UHF J-pole from Romania to see, and it actually works pretty well, but is tight on bandwidth.
Most marine antennas are based on dipoles, I wonder if they’d benefit from the J-pole?
bizarrly, ebay UK has one on sale, but for a band not used in the UK?
I actually got a commercial UHF J-pole from Romania to see, and it actually works pretty well, but is tight on bandwidth.
Most marine antennas are based on dipoles, I wonder if they’d benefit from the J-pole?
bizarrly, ebay UK has one on sale, but for a band not used in the UK?
SIRIO CX-395 (395-410MHz) 3/4 WAVE J-POLE ANTENNA | eBay
: CX 395: 646 mm - Weight (approx.). : 450 gr - Mounting mast: Ø 35-42 mm. ELECTRICAL DATA: - Type: 3/4λ coaxial J-pole - Frequency range @ SWR ≤1.5: CX 395: 395-410 MHz - Impedance: 50Ω - Radiation (H-plane): 360° omnidirectional - Radiation (E-plane): beamwidth @ -3 dB = 60° - Polarization...
www.ebay.co.uk
Since this question is in the General Scanning Forum it’s appropriate to note that J-poles are not appropriate for General Scanning. Their bandwidth is too narrow. That’s fine for something in a narrow bandwidth range e.g. railroad listening. But for General Scanning with a scanner radio wouldn’t you prefer an antenna that works well across a very broad range of bands and frequencies that your radio is capable of receiving? That’s NOT a J-pole, and there are many less complicated and simpler antennas that work well to receive nearly everything a scanner is capable of receiving.
What would be a single antenna good quality and good receiving antenna for 150mhz through470Mhz?
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