I was taught that the term CW (Continuous Wave), was coined to differentiate
between the 'pure' oscillations generated by valves or HF rotary generators and
the quenched or interrupted oscillations generated by spark transmitters?
Martin G4FKK
Walter Blanchard <[email protected]> 31 January 2001 07:51:29 >>>
For some reason this didn't seem to make it onto the reflector first time
round so here goes again:
Recent discussions on "CW" and "Morse" have brought up some interesting
points. Does a mode that is only visually recognisable via a machine count
as "Morse" , or is it another manifestation of digital modulation? If the
effective bandwidths used with QRSS are in the sub-Hertzian range does that
make normally-sent "Morse" a wideband mode that should have no place at
LF? Consider :
"CW" - "continuous wave" - means just that; a steady unbroken unmodulated
carrier wave; "N0N" (or "A0" in old money). Morse code is mainly sent by
interrupting the carrier so how can it possibly be "CW"? Only amateurs
consider "Morse" and "CW" to be synonymous which is a pity because it
clouds our thinking. Sending Morse code by interrupting the carrier is
designated "A1A" (or "150HA1AAN" for typical ham morse if you want to be
pedantic!) - meaning a single carrier amplitude-modulated by a telegraphy
signal. Amplitude modulation (on/off keying) always generates sidebands so
it is by no means "narrow-band" by modern standards. In fact, the faster
Morse is sent the more continuous and wider are the sidebands; the extreme
example of a fast interrupted-carrier system is radar pulsing on/off in
nanoseconds and look how wideband that is. So, "QRSS", because it switches
only slowly and at long intervals is much more entitled to the narrow-band
designation than normal Morse and therefore has more entitlement to be in
the "narrow-band" segment. Nobody has defined when exactly slowly-sent
Morse ceases to be A1A and becomes N0N. Perhaps we shouldn't press the
point, we don't have "N0N" in our licenses!
And what constitutes a QSO under QRSS conditions? The exchange of
information presumably, but what should be the minimum time-lapse between
sending and receiving? Seconds? Minutes? Hours? Days? If I send you a
letter (or even an email) and you reply days later I have achieved
communication with you and the time-lapse is relatively unimportant so why
should radio be different? Just perception?.
Then, perhaps we should have different categories of contact.
An "instant" QSO using "fast" Morse such as we all know and love from HF is
quite difficult to do at LF other than at relatively short ranges. To go
Transatlantic in this mode will require a very "full" 1 watt plus two very
sophisticated Morse ears and a lot of luck and is probably not open to
those who don't have the real estate and cash to put up semi-professional
antenna farms. Nevertheless we don't begrudge the lucky few who can do so
their contest wins on the HF bands so we shouldn't here either. So, one
category for "fast" modes with the proviso that they must complete a
specified minimum QSO within, say, one minute.
Coming down from such heights we get the many who can only put up "small"
antennas and will get electrocuted if they try pushing them to 1 watt
radiated. Their only hope is visual QRSS so a second category for "slow"
modes which would have to complete a QSO within, say, one hour.
Please, no arguments about "players" versus "gentlemen" - you might end up
in the wrong category!
Walter G3JKV.
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