Seems you are very young at age :-)
Earlier users were forced to use MCW on the calling freq in order to be
heard by those stations who were not yet equipped with the "new"
technology to receive A1 transmissions.
Some shiptransmitters used their generator frequency raw rectified,
which produced a 1kHz full modulated transmission.
An early version of a switch mode modulator as we know now.
In those days most vessels had only DC available a generator was
necessary to power the radiostation "at high voltage".
Emergency calls had to be made in this mode. The Autoalarm only reacted
on this mode. Particular in high static regions this was an advantage.
Just like your chirpy mode, it is was quite distinctive for the human
ear within statics.
http://en.wikipedia.org/wiki/Modulated_continuous_wave
DK7FC wrote On 29-5-2014 13:08:
MCW ???
What is that?
73
--
pa3abk <-> dordrecht jo21it
Sent by STB-75 with T100
| 