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Re: [TowerTalk] Is anyone using the 3 feedline approach ontheC31XRfor SO

To: "Mark Beckwith" <>, <>
Subject: Re: [TowerTalk] Is anyone using the 3 feedline approach ontheC31XRfor SO2R?
From: Jim Lux <>
Date: Tue, 05 Jun 2007 10:27:14 -0700
List-post: <>
At 08:35 AM 6/5/2007, Mark Beckwith wrote:
>With malice toward none, I am going to repeat that in the real world people
>are doing this with these Force-12s with excellent results.  How does that
>quote about modeling go?  Too much and it begins to feel like the real
>Shoot, put it up and measure it for goodness sake!
>Better still, ask someone who's already got one up to measure his!

It would be somewhat challenging to model (although an interesting 
problem for a class).. Most filters don't present a very good match 
outside their passband, reflecting almost all the power (but who's to 
say what phase it will have?).  Likewise a stub used to notch a 
frequency will look like a short, reflecting all the power.  But, 
that's connected by a (lossy) transmission line to the antenna, which 
will transform the reflection to something else.

As Mark points, out, measurement might be the way to do it.

And, you can bet it certainly won't be the same at all frequencies 
over a band, nor will it be particularly stable with 
time/temperature/movement of the elements in the wind.

 From a multi radio standpoint, though, all it has to be is "good enough".

Jim, W6RMK 


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