On 17/05/2014 07:07, gareth wrote:

So, having done your matching, you now crank up the output to 1.44kW
by increasing the drive, and those some claimers will now say that the
ouput impedance is now 0.1 ohm.

Hang on there! By their argument, you will now be in danger of severely
damaging your pride and joy by driving into what you say is a complete
mismatch, set, not for 0.1 ohm but for 24 ohms.

And this is why valved PAs in older radios (FT-101Es, for example) had
variable impedance matching (the Pi Tank circuit), and why it's good
practice to tweak that matching after increasing the drive to full power
(say 250mA anode current) having first matched at a lower power (100mA
anode current).