On Jun 12, 12:19*am, Owen Duffy wrote:
Richard Clark wrote innews


On Fri, 11 Jun 2010 20:31:42 GMT, Owen Duffy wrote:
...
I don't suppose this anecdote has any data behind it, does it?

I have performed many tests on many radios. One documented example is athttp://vk1od.net/blog/?p=1045.

The concept is dealt with in more depth athttp://vk1od.net/blog/?p=1028
.

Thing is that those supporting the Zeq=50 proposition, declare that since
the test showed that Zeq (or Zs in the article) is not approximately 50
+j0, then the radio isn't "designed/adjusted for, and expecting a 50 + j
0 ohm load".

Thing is that you cannot use the measured VSWR to reasonably predict the
reduction in power output (Mismatch Loss) on many HF ham radio
transceivers.

I invite you and others to perform the same test. You will realise that
one, or even 100 supporting tests do not prove the proposition, but one
valid test to the contrary is damaging.

Owen

define "mismatch loss".

and why would you expect that vswr is a good predictor of power
output? other than radios that use vswr sensing circuits to reduce
power output to protect their output transistors?

and why would anyone expect the output of an rf amplifier to be linear
except in a narrow range of selected loads and tuning conditions?
thats just plain crazy!