"Copper Cactus" J-Pole

Discussion in 'Antennas, Feedlines, Towers & Rotors' started by W0PWS, Mar 2, 2008.

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  1. N4AUD

    N4AUD Ham Member QRZ Page

    I've only built one J-pole and I have to say I'm very surprised that it would make any difference. I'm still reading about it and have to admit I don't really understand WHY...
  2. JWR

    JWR QRZ Member

    J Pole attachment of feed

    Clearly the long pipe is the radiator. The shield of your coax is at ground potential so why even think about connecting it to the radiator? Just do it right the first time.

    Never, never transmit into an antenna that is not matched. You are depending on the sensing electronics of your transmitter to shut down or limit the output of the transmitter's power. You will either melt your output stage, or radiate little to nothing.

    You can buy your own SWR meter on Ebay for less than you paid for the copper pipe. Because you are measuring relative power, the design frequency of the meter is not important. By a CB SWR and calibrate it according to teh forward power. Now do a reverse reading and you have your ratio of relected power as compared with the forward power.

    I can only show you the door. You have to walk through it. (Neo)

    As to performance, a half wave antenna that is resonating correctly will perform identically whether you call it a J Pole or a Ground Plane or whatever. The only posiible difference is the shape of the field and also the perceived difference of the user and the listener.

    It's all about the resonation.

    Good luck. We are all counting on you.
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