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Re: [Amps] Mismatch loss

To: n8de@thepoint.net
Subject: Re: [Amps] Mismatch loss
From: Larry Benko <xxw0qe@comcast.net>
Date: Wed, 02 May 2012 13:50:49 -0600
List-post: <amps@contesting.com">mailto:amps@contesting.com>
Don,

No, reflection coefficient = sqrt{ [(Rload - Ro)^2 + Xload^2] /  [(Rload 
+ Ro)^2 + Xload^2] } and
SWR = (1 + reflection coeff))/(1 - reflection coeff)

where Ro = characteristic/surge impedance of transmission line and is 
assumed resistive (which is only true for lossless transmission line) 
and Rload and Xload are the load impedances.  The above formula is still 
very close to correct for real transmission lines which always have 
surge impedances of something like 50 - j0.3.

40+j30 and 40-j30 are 2:1 SWRs in a 50 ohm system.

80+/-j60 are an SWRs of 2.76:1 in a 50 ohm system.

73,
Larry, W0QE



On 5/2/2012 1:23 PM, n8de@thepoint.net wrote:
> Shouldn't those last two be:   80+j60 and 80-j60 ??
>
> 73
> Don
> N8DE
>
>> See: http://www.w0qe.com/IC7000_vs_IC706_mobile_pwr.html
>> for power output measurements I made with NO TRANSMISSION LINE for 2
>> radios with 4 different 2:1 SWRs (25+j0, 100+j0, 40+j30, 40-j30).
>
>
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