Ham Radio - The 2-meter twin lead J-pole antenna.

Discussion in 'Amateur Radio News' started by KB7TBT, Oct 20, 2019.

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  1. K5MPH

    K5MPH Ham Member QRZ Page

    On his website he states Class 200 pvc pipe not schedule 40 pvc pipe.the schedule 40 pvc pipe wall are to thick and will cause high swr .......
     
  2. K4FMH

    K4FMH Premium Subscriber QRZ Page

    Thank you! I was writing from memory and had been cutting some 40 PVC. I just checked mine as per Ed’s instructions. It’s 200 PVC. Thanks for helping me not inadvertently spread bad info! 73
     
    K5MPH likes this.
  3. N7MDW

    N7MDW XML Subscriber QRZ Page

    The Ed Fong I just bought (DBJ-1) specified 200 PSI 3/4" pvc. He specifically warns against using sched. 40 as the 200 psi gives much better RF performance.
     
    K4FMH and K5MPH like this.
  4. K4FMH

    K4FMH Premium Subscriber QRZ Page

    Yea, see my reply confessing to bad memory!
     
  5. AG6ZZ

    AG6ZZ Ham Member QRZ Page

    I use an Ed Fong J-Pole; not a copy. He and his grad students use a $40k network analyzer to tune each antenna individually, which no other antenna manufacturer does. I've been to his home. I've seen the network analyzer. He's the real deal, and a really nice fellow. The 200 PVC Ed specifies is only for the J-Poles he sells with the PVC end cap. He also sells a roll-up version, which he tunes for not being stuffed into a PVC pipe. If you have the version with the PVC end cap, you must put it in the 200 PVC pipe for it to be tuned optimally. The PVC affects the tune. Make no mistake, the Ed Fong J-Pole has a very low SWR. Mine measured 1:1 across the 2m band the day I bought it. I forget what it was across the 70cm band (very low, I recall), but I've never tried any commercially manufactured antenna that came close. When I connect my Ed Fong J-Pole on top of a 24' painter's pole to my Elecraft KX3, putting out about 2-1/2 W, I'm heard quite clearly by hams in my community who can't hear me at all when putting out 50W from my car mounted antenna driven by my Yaesu FT-7900. This is on the same frequency at the same location.

    The bottom line is, if you actually do have a well-tuned antenna, and you're not getting acceptable results, move it. In the case of a 2m/70cm antenna, moving it just a few feet can make a noticeable difference.
     
  6. AG6ZZ

    AG6ZZ Ham Member QRZ Page

    Ed Fong also makes a tri-band J-Pole.
     
  7. K6JRW

    K6JRW XML Subscriber QRZ Page

    As K4FMH I have one of Ed Fongs J-Poles..... it works like a charm. I used Schedule 200 PVC recommended and using it primarily for Club/RACES nets here in So. Orange County CA. With hills and canyons I can get into all the VHF/UHF repeaters /simplex frequencies being used for emergency ham comm in our area.
     
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  8. KD8HMH

    KD8HMH Ham Member QRZ Page

    I,have owned 2- of these copper J-Pole antennas dual band 144/450,MHZ, they work great, My first one was on a tower ,back in,Ohio I,painted it white,with a, non- lead paint,I,bought my ,J-Pole from ,KB9VBR,he makes these ,and other antennas also which are made from copper, which is great you put it up on a mast pipe and forget it,.I,had A ,1.1 swr reading on ,2 -Meter at the time I had a,I- com 2200,H 2-Meter, radio eventually I went to R&L Electronics and bought a Mirage amplifier,with 50-in 160 out for transmit,I was able to make a decent contact on the ,east side of Columbus Ohio with no problem,. these J-ploles are worth the money but the ,DB Gain is another thing,they have a, DB Gain of 3 which isn't a lot for this antenna,everything aside ,being constructed from copper ,it will out last a fiber glass antenna ,and probably a, aluminum antenna,.here is the www.site-- www.jpole-antenna.com,and on youtube.com/user/Kb9VBR.73,from KD8HMH
     
  9. W5LZ

    W5LZ Ham Member QRZ Page

    I've never had one of Fong's J-poles, but have made one that I have to say at least gave it a run for it's money. Later changed to a multi-stacked-array type antenna and haven't looked back. If a j-pole ofany type suits you needs it's certainly good enough.
    ... but then, you'll always have that niggling little doubt and think about something 'better'. Right?
     
  10. PA0MHS

    PA0MHS XML Subscriber QRZ Page

    That is most probably due to the radiation pattern of a J-pole, which is almost "flat" when mounted high enough, whereas a car mounted antenna has the centre of the radiation lobe pointing 30 to 40 degrees upwards, so most of your radiated power shoots skyward. This has nothing to do with an antenna being tuned to 1:1 instead of 1:1.5, for example.
     

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