Many out there don't
"John Smith" wrote in message
...
Frank wrote:


You are probably correct concerning a 3:1 SWR. Transmitters
usually have to meet full output into a 2:1 SWR, all phases, with no
sign of oscillation. In this case I had assumed that a matching network
would be used between the PA and coaxial input.

Frank



Everything I have ever ran can handle 2:1 quite nicely, with
transistors, I worry about exceeding that ... or, how big is your
heatsink/fan?

Regards,
JS

If you put a FSM out and start fiddling, you find that some radios don't do
their best above 1.5:1 and many start shutting back past 2:1 and the
internal tuners are only spec'd at being able to match 3:1 or better. Even
after that, there is sufficient loss, that your 100 watt radio is now an 80
watt radio. It may be a neat portable feature, but since you have to get
the antenna down below 3:1 anyway. Might just as well do it right from the
beginning or at least get a big tuner. We didn't worry about these things
with the Pi-net tuning.