> An amplifier capable of
> 3000 watts being operated at 500 watts can easily have more IMD
> than an amplifier capable of 550 watts operated at 500 watts.
>
> 73, Tom W8JI
> w8ji@contesting.com
Working in a linear region, two amplifiers using an identical
configuration and similar devices, if properly biased and tuned for the
wanted output level, doesn't necessarily produce an IMD advantage for
the larger one compared with the smaller amplifier, although in most of
the cases their IMD figures are quite comparable and acceptable.
Things anyway quickly go in favour of the bigger amplifier when the
smaller amplifier is starting to compress more in order to obtain a
stated output power level.
As a matter of facts and expecially with smaller amplifiers, some of
the manufacturers claim irreal output levels and others "forget" to
explain that beyond a certain output power their amplifier is already
compressing a lot.
On the other hand, amateurs are prone to believe in miracles and tend
to (largely) overdrive smaller amplifiers in order to obtain more power
(often the manufacturer claim is already too much) and expecially to
obtain more reading from their AVG wattmeters, whose fact is well
obtained when the PA is compressing.
73,
Mauri I4JMY
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