Ralph Mowery wrote:

Most ham rigs ( and many more "12 volt devices" ) are specified to put out
the designed power at 13.8 volts. This is a nominal voltage of a car with
the moror running. Any less voltage and you usually get lower output and at
a higher voltage you may get slightly more output.

There are always minor virations in the power output at the same voltage
from differant rigs of the same type. Most have a way of adjusting the
power output to a small degree to bring them back to the nominal power.



This is what I suspected but it was suggested to me that rigs are
designed with a good margin of power in mind so that they will give
rated output at the lower end of the supply voltage range.

I just fixed up an IC746PRO and found that at 13.2V, I only got 70W
instead of 100W. Then I found a drop of 1.3V in the factory supplied
leads (4m long). Shorter leads put this up to 80W but still short of the
rated output. I run all my radios on batteries and don't have a proper
13.8V supply so I don't know if the 746 is working to spec or not.

Alan