Hi Jan,

Am 29.05.2014 14:22, schrieb pa3abk:

Seems you are very young at age :-)

No, i became 38 some days ago...

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.

Aah, that's a good idea! ;-)

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

Thanks for the informations.

73, Stefan

DK7FC wrote On 29-5-2014 13:08:

MCW ???
What is that?
73