Whoa, I did that experiment for Slick a month ago. I replaced the short
piece of LMR240 between the transmitter and Kenwood SW2000 meter with a
precisely measured 1/4 wavelength piece of RG59 75 Ohm coax. The loading
changed, as expected, but the SWR reading did NOT change for SWR values of
1:1 and 1.6:1. The transmitter now saw a load of 112.5 Ohms. The Kenwood now
saw a different source impedance.

I don't see any inconsistency. 100W into 112.5 Ohms requires a voltage of
106V RMS. In a transmitter with a fixed ratio output transformer that may
not be doable. It is designed to put out 70.7V RMS into 50 Ohms, with some
margin.

Tam/WB2TT
"Reg Edwards" wrote in message
...
To anybody interested.

We have a HF Transmitter + 50-ohm coax + SWR meter + Tuner + Feedline of
any
Zo + Antenna.


Suppose it is all tuned-up and ready to go. The transmitter is loaded
with
exactly 50-ohms resistive.


Now change the 50-ohm coax to shorter length of 75-ohm Zo.


As everybody agrees (after perhaps a little meter recalibration) the SWR
meter indication will not change. BUT THE TRANSMITTER WILL NOW BE
INCORRECTLY LOADED.


Where does the inconistency lie ? Does it lie in the change in effective
source impedance?