In a message dated 4/12/00 10:16:44 PM GMT Daylight Time,
[email protected] writes:
<< Very few signals generated by such amplifiers and used by radio amateurs
have
a pure sine wave output after one 5 pole LPF, except at very low power
levels, >>
Hello.
I think you will find that the relative level of harmonics (dBc) will depend
on the characteristics of the LPF and source / load impedances i.e. the
correct filter terminating impedance, and not the applied power levels.
Equally: The relative level of radiated harmonics (dBc) is generally
speaking independent of antenna whether it's at 130 feet or a long wire a
"few feet off the ground"
"amateurs....push class D/E amplifier too hard" - With square wave drive the
harder they are driven, the better they are.
No one has a pure sinewave output.
A low pass filter will not remove key clicks as they are within the passband
of the LPF.
90% of multikilowatt MF broadcasters use class D/E etc.
Surprisingly, the UK amateur radio licence allows up to 1% of energy to fall
outside the amateur bands, so this would not be of any interest to the RIS.
In anycase 250Hz is 'inband' and would be considered a problem to be resolved
by the band's users. - If it was considered a problem at all.
Using a computer and spectran / gram clearly demonstrates the larger
bandwidth occupied by fast CW transmissions. As the band is very narrow,
should we put an upper speed limit on CW - to limit the occupied bandwidth?
(Hi)
Goodness Mal. They only had a mast bigger than yours.
"So many negative vibes" - Donald Sutherland.
73
David
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