[amsat-bb] Re: Cushcraft 416-TB

Howard Kowall hkowall at shaw.ca
Wed Mar 23 07:02:45 PDT 2011

Hello David
I did think about that also
I also though maybe the balun didn't make it 50 ohms but maybe a much high value
But when i fed the ver driven element with  50ohm feed line and checked the swr with just a meter it was ok so that ruled that out.
I realize the circular porization was done by the physical location of the driven elements,
Thanks very much David

  ----- Original Message ----- 
  From: David Greenberg 
  To: Howard Kowall ; AMSAT BB 
  Sent: Wednesday, March 23, 2011 8:50 AM
  Subject: Re: [amsat-bb] Cushcraft 416-TB

  Hello Howard,

  From the cable length that you measure it looks like 3/4 Lambda instead of 1/4 Lambda which is too short for convenience working. From the electrical point of view it is the same, assuming low loss coax.

  David 4X1DG
    ----- Original Message ----- 
    From: Howard Kowall 
    To: AMSAT BB 
    Sent: Wednesday, March 23, 2011 3:28 PM
    Subject: [amsat-bb] Cushcraft 416-TB

    Hello All
    I acquired a Cushcraft 416-Tb antenna,the so called phasing harness was in bad shape,so I am going to make a new one for it.
    I could copy the original one,but yes I am making it hard on myself and decide to calculate the proper cable type and length,and to do that I need to know how the antenna actually works.Here is my problem ,the 2 driven elements have a balun to each of the Tmatchs to make the impedance 50 ohms on each driven element.The original phasing harness is 2 piece of 75 ohm aprox 13" that goes to each driven element and the a so239 connector on the other end of the harness is the 50 ohm feedline.I originally thought this was a matching stub,but when I do the calculation for the matching stub,should only be aprox 4" to each driven element.Am I missing something here,how are they able to do this,does anyone know this antenna and how it works.
    Thanks to all who read and respond in advance
    Howard VE4ISP

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