R: [AMPS] Re: swr

[Maurizio Panicara]

John,

concerning the point "a", source line and load, I was not talking of SWR
changes but of impedance changes between antenna and transmitter, moreover
as a direction and not as a versus.

The best condition to transfer energy is that generator and load have the
same impedance. A 100 Ohm transmitter used to feed the combination of a 50
Ohm line and load, independly by the SWR @ 50 Ohm, will work in a badly
mismatched condition, similarly to a transmitter looking into a load that
causes high SWR.

This consideration has twice sense because in the amateur world the
transmitter antenna is very often also the
receiving one (a source) and creating a symmetrical condition where no
impedance transformations occurs is quite a desiderable condition to
preserve.

Concerning the point "b", the half wave multiples, you're right and I
apologize not to have specified again about the most obvious and known
property of the transmission lines many times threated.

73,
Mauri I4JMY


-----Messaggio Originale-----
Da: John Devoldere (ON4UN) <john.devoldere@village.uunet.be>
A: Maurizio Panicara <i4jmy@iol.it>; Gilmer, Mike <mgilmer@gnlp.com>; 'AMPS'
<amps@contesting.com>
Data invio: mercoledì 29 settembre 1999 0.28
Oggetto: Re: [AMPS] Re: swr


Let me "improve" this a little:

a/ line and load have same impedance  (the matching condition at the
"observing  end" of the feedline does NOT influence the SWR!)
b/ the line is a half wavelength or multiple of half wavelengths long

73

John, ON4UN


----- Original Message -----
From: Maurizio Panicara <i4jmy@iol.it>
To: Gilmer, Mike <mgilmer@gnlp.com>; 'AMPS' <amps@contesting.com>
Sent: Tuesday, September 28, 1999 20:07
Subject: R: [AMPS] Re: swr


>
> Not considering losses, there are only 2 conditions were no changes in
> impedance occurs between antenna and transmitter :
>
> 1 ) Source, line and load have the same impedance
> 2 ) The line is half wavelenght
>
> 73,
> Mauri I4JMY




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