[Elecraft] Point me to the note for sending CW when in, SSB mode

[Ron D'Eau Claire]

Quite right Vic. A.M. MCW was *required" for any emergency maritime
communications. Up until well after WWII, some ships still had crystal
detectors as the 'emergency' receiver should the main receiver fail. In any
case, A.M. MCW received on a superhet produced a very distinctive sound that
made it stand out from other traffic and was required or any shipboard CW
transmitter. 

Unfortunately many marine radio operators never turned the modulator on. One
of the biggest jobs I had when preparing a ship's CW console for the annual
FCC SOLAS inspection was to get the transmitter working in MCW mode. After a
year of collecting dusty salty grime, it was not uncommon to fire up the
modulator and have the final amp tank circuit insulators or the antenna
switch erupt in flames due to the much higher peak RF voltages produced when
the signal was modulated. Lots of scrubbing with rags and alcohol was then
required to get the carbon and salt grime off of all the insulators, HI! 

Some of the early commercial (1960's) SSB rigs offered CW capability with a
built-in audio oscillator that fed into the transmit audio. That is not MCW,
but pseudo CW. It would be CW if the audio oscillator was a perfect sine
wave and the carrier and opposite sideband suppression were perfect so that
the only RF transmitted was the sideband produced by the audio oscillator.
But, of course, it never is...

73 Ron AC7AC

-----Original Message-----
From: elecraft-bounces at mailman.qth.net
[mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Vic, K2VCO
Sent: Saturday, June 15, 2013 8:24 AM
To: elecraft at mailman.qth.net
Subject: Re: [Elecraft] Point me to the note for sending CW when in, SSB
mode

I wish people would stop using the term 'MCW' for the method of producing CW
by feeding a (one hopes) clean audio tone to an SSB transmitter. This is a
way of generating CW -- which may or may not be the best way -- but it is
not MCW.

MCW as it has always been understood is a carrier modulated at an audio
frequency -- an AM signal. The signal is keyed on and off to transmit Morse
information, but it has two sidebands on either side of a carrier. 
If the tone is, say, 600 Hz, then the signal will be at least 1200 kHz wide.
It is illegal in our HF CW bands.

MCW was used in past years for maritime communication because it can be
received by a receiver without a BFO and there is no 'zero beat' 
phenomenon which could cause a listener to miss a signal.