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Re: [Amps] High SWR

To: Paul Christensen <w9ac@arrl.net>
Subject: Re: [Amps] High SWR
From: Roger <sub1@rogerhalstead.com>
Date: Fri, 24 Apr 2009 00:23:08 -0400
List-post: <amps@contesting.com">mailto:amps@contesting.com>

Paul Christensen wrote:
>> Back when I was in broadcasting full-time, VSWR was important, too.
>>     
>
> VSWR in broadcasting applications is especially a concern when complex 
> modulation schemes are used.  FM stereophonic separation is highly dependent 
> on line VSWR.  Line reflections degrade stereo performance.  In NTSC 
> television transmissions, line VSWR causes "ghosting."  Even modest amounts 
> of VSWR can degrade audio and video performance.
>
> As broadcast operations turn more toward digital modulation schemes, VSWR is 
> still important for proper decoding albeit some modulation schemes are more 
> or less susceptible than others.
>   
I would say it's more important with digital than with analog.   
Digital, like the analog TV does not do well with those waves running up 
and down the line. At least, unlike networks you don't have to worry 
about signals from the receiving station, BUT the antenna can reflect 
signals back to the transmitter degrading those that are headed out. Our 
only saving grace is the ones going out are a lot stronger than the ones 
coming back.<:-))
73

Roger (K8RI)
> Paul, W9AC
>  
>
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