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Re: LF: (More) Nonsense from Kev

To: [email protected]
Subject: Re: LF: (More) Nonsense from Kev
From: [email protected]
Date: Wed, 12 Apr 2000 19:55:01 EDT
Reply-to: [email protected]
Sender: <[email protected]>
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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