Guess that is the right answer Jim.
Jos on4kj
----- Original Message -----
From: "Jim Wilcox" <jim.wil@cox.net>
To: "Van Fair" <vfair@innova.net>; <towertalk@contesting.com>
Sent: Wednesday, October 15, 2003 7:11 AM
Subject: Re: [TowerTalk] Question concerning Hard Line
> Hello, Van--
>
> Keep in mind that the SWR meter is designed to operate with a given
> impedance--almost certainly 50 ohms; it will produce erroneous readings
when
> connected to other impedances (input or output). In other words, you
can't
> trust the meter readings you obtained; they almost assuredly are
incorrect.
>
> Further, even if you could trust the meter, there will be an impedance
> transformation caused by the 70 ohm line. I now have to bow to those more
> knowledgeable to provide details about that, but I would not expect
radical
> SWRs to result if those feedlines and the connections are good. My guess
is
> that the 2:1 readings are more a result of the fact that the meter is
> designed for 50 ohms.
>
> Good luck--it'll be interesting to see how this plays out.
>
> vy 73
>
> Jim, W3WV
>
> ________________________________
> Jim Wilcox
>
> ----- Original Message -----
> From: "Van Fair" <vfair@innova.net>
> To: <towertalk@contesting.com>
> Sent: Tuesday, 14 October, 2003 21:46
> Subject: [TowerTalk] Question concerning Hard Line
>
>
> A friend has 60 to 70 feet of hard line (type unknown) buried to his tower
> and then RG8 up the tower. On the transmitter end it has 10 feet of RG8
> before the hard-line.
>
> He is having a problem with high SWR on his beam. In checking it out I put
a
> 52 ohm dummy load at the end of the hard line at the base of the tower and
> found a 1-1 SWR at 12.53, 20.71 and 16.63 MHZ. Over the rest of the freq
the
> SWR was much higher including 2-1 at 14.2, 1.9-1 at 21.3 and 1.5 -1 at
28.6
> MHZ. This seems abnormal and my experience says it should be close to 1-1
> on all freq. but I have only used 52 ohm coax. The hard-line may be 72 -
75
> ohms. Would this cause the above type of readings or does this indicate
some
> other problem.? It seems to me that mixing hardline and coax of different
> impedance is not good but does it work?? Thanks Van
> _______________________________________________
>
> See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless
> Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with
any
> questions and ask for Sherman, W2FLA.
>
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>
> _______________________________________________
>
> See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless
Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any
questions and ask for Sherman, W2FLA.
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
>
>
_______________________________________________
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather
Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions
and ask for Sherman, W2FLA.
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