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The j-pole antenna is fixed...

Discussion in 'Amateur Radio News' started by KX4O, Jul 9, 2020.

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  1. K7JEM

    K7JEM Ham Member QRZ Page

    I had a pocket J-pole I built back in 1980, out of home grade twin-lead. That antenna worked great, had about 10dB of gain over an IC-2AT rubber duck antenna. Worked well for years.

    I built a J-pole variant about 10 years ago, and it worked well, too. It consisted of a QW coaxial stub instead of the usual open wire stub. The stub was around 12" long for 2M, shorted at the bottom, and fed about 1.25" up from the bottom with coax. The antenna was around 39" of wire attached to the top center of the stub. I hung the antenna from the inside 9' ceiling for testing, and it worked very well, at least as good as any other HW antenna. That antenna would be easy to build and mount inside a 3/4" PVC pipe, with a ferrite placed at the feed point.
    K8XG likes this.
  2. W1YW

    W1YW Ham Member QRZ Page



    Thanks Erika:)

    Stay well:)

    Chip W1YW
    K8XG and K0DD like this.
  3. N0TZU

    N0TZU Platinum Subscriber Platinum Subscriber QRZ Page

    I also made one of those roll up j-poles, with the thin translucent TV twin lead, back in the early 90’s. I still have it and it works well - that is, much better than a rubber duck.
  4. KE4IKY

    KE4IKY Ham Member QRZ Page

    In the defense of the "I've seen parts of this before" The shorting stub to reflect an open is discussed in
    Nov 2004 - QST (Pg. 61)Experiment #22--Stubs, is a source,

    as well as (Module 18 page 2-21 or so).

    It's a little more complicated, but on radars the quarter wave stub has been used for many years.

    It is a novel use in this J-pole instance.

    K8XG, W1YW and KX4O like this.
  5. W3ATT

    W3ATT Ham Member QRZ Page

    Ahem, Chip... From your previous post:

    "Comments have consequences. Let's use good judgement in making them."
    KD2NOM likes this.
  6. W1YW

    W1YW Ham Member QRZ Page

    Exactly. The very best of judgement. Backed by 65 years of experience on the matter.

    Ask him about his deleted posts on Jewish business leaders.

    Ask if that call was ASSIGNED to him by the FCC, or whether he specifically requested it.

    Ask why those posts were deleted.

    Again, I think it's peachy cool that the FBI owns this antenna, and is likely monitoring the various posts. FB with me.

    Chip W1YW
    Last edited: Jul 13, 2020
  7. K8XG

    K8XG XML Subscriber QRZ Page

    Cactus Antenna !
    WJ4U, W1WWA and W1YW like this.
  8. K8XG

    K8XG XML Subscriber QRZ Page

    Typical Lib Run University
    W1YW likes this.
  9. KX4OM

    KX4OM Ham Member QRZ Page

    Replying to myself, I reject my previous post. After reading the patent history of John Huggin's patent application, I note that it was initially rejected by the USPTO. Also, I note that in the details of the patent, a lot of prior art is referenced. The patent seems to stand on the assertions that combinations of the details of prior art designs do not exist. For example, designs with decoupling stubs lack the direct path to ground for current from lightning, and other designs do not include feedline inside the mast while incorporating a decoupling stub, etc. There are many combinations of prior art that have to be considered.

    Also, the applicant's employment with the FBI mean that US Government entities may use the patent without payment.

    Ted, KX4OM
  10. K8XG

    K8XG XML Subscriber QRZ Page

    What would be the problem with that? You know they wont be charging folks for using that data....

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