Buck wrote:

I believe he is right. Radios drop power when they don't like the SWR
and raise it when it does.

That depends on the radio.

Without SWR protection one with a class C final, like the ones in the
little QRP rigs I have lying around, will deliver more power if it sees
a lower RF impedance at the final transistor than it was designed for.
It will also overheat said final transistor* and possibly damage it.
This will happen for some SWR mismatches but not all.

Again without SWR protection one with a class AB or B final, properly
tuned for a 50 ohm resistive load, will deliver less power for some
mismatches (the same mismatches that would be _higher_ power for the
class C final). With other mismatches it would exhibit higher gain but
more distortion. At some mismatch and level of drive you could probably
expose the finals to too much power dissipation, too high an RF current
or too high an RF voltage, and do damage. This depends _heavily_ on the
design of the final stage.

With SWR protection, of course, the radio will automatically back off,
perhaps even in a way that will do some good.

So I will use an SWR meter to keep the transmitter happy, and a field
strength meter to make sure my antenna is doing it's job.

* assuming I got the heatsink design right, neither overly conservative
nor overly optimistic.

-------------------------------------------
Tim Wescott
Wescott Design Services
http://www.wescottdesign.com