Re: QDX with Elecraft T1


Paul Christensen
 

On Fri, May 13, 2022 at 03:36 AM, Roelof Bakker wrote:
"These calculations are not correct as the source impedance (your transmitter antenna port) is not 50 ohm. It must be connected to a 50 ohm load, yet is not 50 ohm itself."

Wolfgang's result seems correct to me based on SimSmith and TLW models.  Most loss occurs in: (1) the 3m line section between the ATU and load; and (2) inductor loss in the T tuner.   I modeled using RG-58 coax.  See results below.

SimSmith includes the 1.5m jumper inserted after the source but it's not included in the TLW model as it can't manage multiple network elements like SimSmith can.  However, that section of the line is matched and as such, matched loss is small relative to other loss which gives similar results between the two modeling programs.

Comments?

Paul, W9AC   

 

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