Subject: | |
From: | |
Reply To: | |
Date: | Mon, 1 Mar 2004 08:07:49 -0800 |
Content-Type: | TEXT/PLAIN |
Parts/Attachments: |
|
|
This swr thing gets a little complicated. Let me see if I can expalin it.
It is basically an impedence ratio. So, if the load is 25 ohms the swr is
2 to 1 and if the actual load is 100, then the swr is still 2 to 1. Then
enter into the picture reactance and so forth. Let me think if I can
recall the formula if you know forward and reflected power in watts. I
think it is first quantity square root of forward power plus square root
of reflected power divided by second quantity of square root of forward
power minus square root of reflected power. all in watts. Roughly, a 4
percent reflected power in watts is 1.5 to 1 and 11 percent comes out
close to a two to one swr. Using my example above, let say you are
running a hundred watts and your reflected power shows ten watts. You
have ten plus 3.16 and second quantity of 10 minus 3.16 or 13.16 over 6.84
which comes out 1.92. This is your swr in this example. You are correct
in that final components must disipate this pawer and feed lin e does as
well. But, as you see by above example, a 1.5 to one is only around 4
percent reflected.
Hope all of this helps and makes ssense.
73s
Butch Bussen
wa0vjr
|
|
|