Hi,again
When the cable between exciter to amplifier is longer
than 30-50cm, a tuned input will always help for both
configurations.How much ? 2dB or maybe litlle bit more
is in my opinion a nice improvement in IMD. It will be
quite expensive, but if you're gaining another 5-8dB by
using a good quality tube, another 3-4 dB from a proper
designed circuitry around the tube, you'll get a much,
much clean signal. Maybe you don't know what's the
situation in Europe where they are still thousand of
"dirty" transmiters and linear using 1950's tubes, concepts
and technologies. Figures of 10-20db TX IMD are not rare
at all. Plus thousands and thousands of operators with no
ideea on splatters, ALC, compression levels and so on.
I was born in eastern Europe where I spent 15 yrs of my ham
radio life so,I know very well the russian tubes,equipments
and concepts. Of course, they are too a lot of western amps
and ops with "dirty" signals.
Try to ask few well-known contest teams from old soviet
republics,serbs, slovens or croats what amplifiers are they
using. I have nothing against the use of power but I want it
"smart & green" not " brute & dirty ".
By the way, I was shocked to heard few days ago a well known
contest operator telling to Martti, OH2BH how he's working on
WPX SSB: 4kW output from a 1955 class "C" russian amplifier
used for jamming "Voice of America" in the cold war and
deliberate use of a 20dB's of compression to keep some
competitors far away from his frequency. Another famous 9A
contester is using an old 5KW 13.56MHz heating oscillator.
I can hear him 25KHz around his frequency,from 1000 miles
distance and the problem is not on my FT-1000D front-end or
filtering.
73 de Morel, 4X1AD
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