[BC] "VSWR" Metering

[cldube]

Thanks Cowboy.

(didn't I hear that line in a film?)

I've watched a transmitter deliver into a fire once. It wasn't pretty 
(fortunately [for me- that is] it wasn't my transmitter- all things being 
relative).

Chuck
----- Original Message ----- 
From: "Cowboy" <curt at spam-o-matic.net>
To: "Broadcast Radio Mailing List" <broadcast at radiolists.net>
Sent: Monday, October 17, 2005 11:35 AM
Subject: Re: [BC] "VSWR" Metering


> On Sunday 16 October 2005 05:52 pm, cld at admin.umass.edu wrote:
>>
>>These have been great and informative comments. Thank you gentlemen. May I
>>boil it down to "a vswr meter is valuable for viewing the antenna system 
>>match
>>to the transmitter in general (for those of us without access to a TDR), 
>>but a
>>good vswr indication should not be taken as gospel truth that there isn't 
>>a
>>mismatch somewhere"?
>
> I'll take that.
>
>>Which brings us to the next question- if indeed you see a "good" reflected
>>power indication at the tx output, but still suspect something is awry, 
>>what,
>>in your opinions, are the best places to look (and let's say that you 
>>don't
>>have the ability to climb a tower and check the vswr at different points 
>>nor
>>have access to a TDR). Efficiency?
>
> I'd look first at transmitter loading.
>
> Next, add 1/4 wave of line between the meter and the load, and read
> it again.
> Ignoring the absolute value of the numbers, the important question
> is whether or not you see a change.
>
> Efficiency is not valid, as the transmitter may well show the same as long
> as it's delivering the same power, whether into a good load, or a fire.
>
> -- 
> Cowboy
>
> http://cowboys.homeip.net
>
> "It's not Camelot, but it's not Cleveland, either."
> -- Kevin White, mayor of Boston
>
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