Hi Jim,
> overhauls. A small amp pushing the limits of its linearity will cause more
> TVI and side splatter than a larger one putting out the same power, again
> assuming similar operating modes.
TVI has absolutely nothing to do with "headroom" in the PA. It is
entirely a function of the layout and shielding integrity.
"Side splatter" (as opposed to "up and down splatter") is not
necessarily related to headroom either. 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.
By far the most common cause of IMD is improper tuning, or
improper screen and bias systems in tetrodes when the IMD is
predominantly from the PA.
In the real world, most IMD is from the exciter with any reasonable
amplifier design.
It's amazing how bad most rigs have gotten, and this especially
aggravated because some people think that a just because a radio
can put out 200 watts they can turn the internal power limiting
controls up to 130 watts or more without ill effect.
73, Tom W8JI
w8ji@contesting.com
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