Amps
[Top] [All Lists]

[AMPS] Re: The Worldwide, No Holds Barred, SWR Quiz.

To: <amps@contesting.com>
Subject: [AMPS] Re: The Worldwide, No Holds Barred, SWR Quiz.
From: measures@vcnet.com (measures)
Date: Tue, 5 Oct 1999 01:26:39 -0700
>
>measures wrote:
>
>>>Not if the impedance of your transmission line is the same is the 
>>>impedance of your source.  Draw it out on a Smith Chart, Rich.
>>>
>>?  In this case, the impedance of the source/generator is zero ohms, the 
>>characteristic impedance of the half wavelength transmission line is 93 
>>ohms, and the termination is 50-ohms. 
>>
>>>You move along a constant VSWR circle with 50 Ohms as the center of that 
>>>circle.  The radius of the circle is the magnitude of the VSWR.  This 
>>>assumes a 50 Ohms sytem and a Smith Chart normalized to 50 Ohms.
>>>
>>"This is assuredly not a 50 ohm system due to the presence of the half 
>>wavelength 93-ohm coax."
>
>Rich,
>
>MUST you debate everything?  Even when somebody agrees with you?
>
>It IS a 50 Ohm system because you are defining the measuring device as 50 
>Ohms.  Therefore, you want to see what the SWR with a 50 Ohm device is.  
>So you use the 50 Ohms as your characteristic impedance.
>
>Now, you are correct in that it matters not what the impedance of your 
>source is.  I thought more about this.  All that is being done in your 
>example is using a 50 Ohm instrument to measure the VSWR.  And at the 1/2 
>wavepoint in the 93 Ohm coax we have a 50 Ohm impedance, hence the 
>instrument reads 1:1 SWR.  It matters not if the meter and the source are 
>matched or not since the meter is only interested in what is after itself.
>
>Please though, Rich.  I agree with you.  Enough debating on this!
>
?  Let me see if I have this straight.  You agree that the 50-ohm SWR 
meter will read 1:1 at the ends of the 1/2 wavelength section, and that  
it will read 1.86:1 at the 1/4 wavelength point?
-  thanks.  


-  Rich..., 805.386.3734, www.vcnet.com/measures.  


--
FAQ on WWW:               http://www.contesting.com/ampsfaq.html
Submissions:              amps@contesting.com
Administrative requests:  amps-REQUEST@contesting.com
Problems:                 owner-amps@contesting.com
Search:                   http://www.contesting.com/km9p/search.htm


<Prev in Thread] Current Thread [Next in Thread>