[Amps] Why hasn't solid state replaced tubes?

[peter.chadwick at Zarlink.Com]

Tom said:

>IMD (splatter) is not considered spurious emissions by ICOM. All that
tells
>you is harmonic suppression.

This is probably because the International Radio Regulations don't call
close in IMD 'spurious emissions' either. In professional circles, they are
called 'Out of Band Emissions'. Out of Band emissions are those within 2.5
times the necessary bandwidth, which for HF amateur purposes is 4kHz. (This
was to stop a requirement for IMD at 50dB at 5.25kHz getting into the Radio
Regulations for the amateur service) Spurious emissions and unwanted
emissions are all classed as 'Unwanted Emissions'. The differentiation
seems academic at HF, but isn't so for the satellite community. Usual
professional SSB transmitters are -31dB relative to PEP: even this is only
just good enough for ISB.

I believe a number of people have commented that many of the transceivers
available now still dominate the overall IMD performance when an amplifier
is added.

73

Peter G3RZP