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

[Fred Jensen]

In the marine CW service in the late 50's, nearly all traffic on the 
Holy Wavelength [600m] was MCW.  After all, it was the worldwide 
distress channel.  A lot on working frequencies was too.  Unlike MCW on 
the VHF ham bands, the RF carrier was also keyed, but in either case, it 
was double-sideband amplitude modulation.

Shipboard transmitters usually employed motor-generator sets to get the 
high voltages necessary from the ship's DC mains.  They weren't filtered 
well and most transmitters afloat were modulated by M-G whine.  The M-G 
sets also weren't well regulated so the voltages rose and fell with the 
CW.  The result, if you listened with the BFO on, was a chirping carrier 
modulated by a chirping audio tone with a chirping whine in the 
background.  It was "distinctive" as Ron says but generally less than 
harmonious. :-)

None of this MCW drivel has anything to do with the CW scheme for SSB 
transmitters, pioneered if not invented by Collins in their KWM2 and 
S-line equipment.  It worked for Collins because their mechanical filter 
suppressed the opposite sideband by something like 70-80dB, the balanced 
modulator had good carrier suppression and the filter added to that, and 
they generated a very clean sine wave.

73,

Fred K6DGW
- Northern California Contest Club
- CU in the 2013 Cal QSO Party 5-6 Oct 2013
- www.cqp.org

On 6/15/2013 10:04 AM, Ron D'Eau Claire wrote:
> 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.