Tom said:
>Look at the TS-2000 as an example. It is almost class C quality, yet
>reviews all ignore that fact.
Not quite Class C - it would be about 7 or 8 dB worse in that case! Tom is
correct though - it is really unacceptably poor.
>Keyclicks are designed in by manufacturers using excessively fast rise
>and fall times
I believe there are two parts to this:
1. A demand (or a belief that there's a demand) for rigs to be regularly
operated at 50 or 60wpm.
2. A failure to look on a spectrum analyser at the design stage with the
transmitter keyed with a square wave at 30wpm or so.
This latter may well be because there aren't that many designers of transceivers
who actually are operators, especially CW operators.
If transmitters met the old marine specs, it would be an improvement.
Incidentally, in my recently built 'classic' 807 tx, I found that it was
impossible to get down to 99% power bandwidth of 250Hz (as per ITU
recommendations) at 30 wpm dots without excessive rounding of the characters. I
could get it within 400Hz, though. The 'break' seems usually to be the problem,
but not in this case.
And I still don't go a bundle on ALC!
73
Peter G3RZP
--
FAQ on WWW: http://www.contesting.com/FAQ/amps
Submissions: amps@contesting.com
Administrative requests: amps-REQUEST@contesting.com
Problems: owner-amps@contesting.com
|