[TowerTalk] 75 ohm - v - 50 ohm coax

[Steve Hunt]

If the antenna has an impedance of 50 Ohms, and the coax is close to a 
quarter-wave or odd multiple long, you'll see an SWR(50) of 2.25:1 at 
the shack end instead of 1:1.

73,
Steve G3TXQ



On 18/02/2013 13:03, John E. Cleeve wrote:
> Good afternoon gentlemen,
>
> A 100 metre(325ft)drum of 75ohm, 25mm(1 inch) diameter coax, and the
> appropriate connectors, has been donated to my GM project, for which I am
> very grateful.
>
> I am considering using this coax as one of the feeders buried to a
> distribution point out in "the aerial field". My question is, from the
> groups experience, would I notice any serious difference in the aerial
> matching etc, between the use of 50 ohm and 75 ohm coax at HF.
>
> I have yet to set up a practical experiment, to measure the loss etc.
> using differing resistive terminations, but that will be done when the
> cable is unwound, before the cable is installed.
>
> I would appreciate your thoughts/experience.
>
> Sincerely, John, G3JVC/GM3JVC.
>
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