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Hi Laurence and all,
Am 30.08.2012 19:18, schrieb Laurence KL7UK:
Thanks G I can/could go comm port keying but prefer the audio
being lazy.-
it appears in my set up that the rise time is very short and
less than the 5mSec thats generally accepted as required hence
the click - but Im sure Im seeing more than just the first rise
of the sine, Ill do some more delving - but Im sure the
software could be make more soft with a slower ramp as done on
Markus' Chirpix and some of the PSK programs - It appears to be
an anomoly with only Opera here? Am I alone?
Certainly not. I was also a bit annoyed by keying clicks (not only
from Opera though).
A smooth ramp wouldn't cost much, and certainly will not affect the
'average power' since there are not so many on/off transitions. From
the software side, this should be extremely easy to implement (for
"audio driven" linear transmitters).
The problem may be for people with hard-keyed ("brutally on/off
keyed") transmitters, where the driving circuit may play havoc when
fed with low input amplitudes.
But imho, for someone capable of building a large antenna, a large
amplifier, etc etc, it shouldn't be too difficult to provide an
adequate keying circuit either by modulating the DC supply voltage
or similar means.
"A simple on/off keyed CW transmitter" without envelope shaping may
be ok for QRP experiments but not for QRO on a crowded (?) band.
This applies to LF, MF, and HF. Almost as bad (but often seen on 40
meters): Transmitter putting out a nicely shaped amplitude ramp, but
a terrible power amplifier, completely overdriven, which completely
removes the amplitude ramp or shortens it to fractions of a
millisecond (i.e. clicking "bandwidth" in excess of one kHz).
All the best,
Wolf DL4YHF .
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