The onset of the generation of unwanted
components is relatively sudden.
Driving the amplifier with the minimum
required output power results in a "clean" signal.
There should be a simple linear relationship
between input and output powers for instance :-
input is 10 Watts, output 80 Watts,
input 20 Watts, output 160 Watts, etc.
input 40 Watts, output 320 Watts, etc.
When the linear relationship starts to
fail for example :-
input 40 watts gives only an output
of 300 watts in stead of the expected 320 watts
then you have reached the point of over
driving the amplifier which may cause harmonics and/or spurious intermodulation
products.
Also the result of not reducing the
drive is an increase in spurious intermodulation products and harmonics products and
harmonics, using unnecessary bandwidth, and possible damage to the
amplifier.
Do not to overdrive but operate below
maximum ratings.
For those who know a thing or two about
power - and that should be all readers - a small reduction in output power
level will give a negligible variation to the strength of received signal.
A doubling of power is usually needed to raise the "S" meter by half a point
(but this does depend upon the calibration of the "S" meter on your rig.
So dropping power to 350W from 400W and having a clean signal will lose you
only a fraction of an "S" point. |