Kevin Stover said "...audio injected CW, really afsk,..."
Isn't afsk really audio frequency-shift keying as commonly used for RTTY on
VHF?
The signal produced by a well-adjusted SSB rig with a pure keyed tone
injected will be pure CW, undetectable from any other CW signal. The things
to be concerned about to achieve that, other than a decent keying waveform
on the audio signal, are adequate carrier and opposite sideband suppression.
On the CW bands, any carrier or other sideband leak would be simply a
"spurious" emission and would have to meet all the FCC requirements for the
level of such emissions.
Ron AC7AC
AFSK is audio-frequency-shift keying and that's what the majority of
Hams using the sound card for RTTY on HF are using. Check me if I'm
wrong but if the sound card produces a pure sine wave audio signal of
say 600Hz how would you distinguish that from a hard keyed CW signal
unless it's got harmonics spread out over the 2.5Khz audio bandpass?
How do the rise and fall times of the SSB and CW waveforms compare?
Isn't SSB, even with VOX delay turned all the way down, a lot slower
than CW? If the SSB rise and fall times are slower than CW how do you
get clicks?
I would agree that nobody in their right mind would cut loose with
800wpm HSCW on the HF bands becasue of the bandwidth used. I can't
remember the old formula for figuring the bandwidth for CW signals of
any arbitary speed.
--
R. Kevin Stover ACØH
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