Summer 1968 : My First Reception of Weather Satellites Automatic Pictures Transmissions (APT)

At the end of the 1960s I became interested in the reception of the pictures transmitted by the then new TIROS and ESSA weather satellites : this was a completely new field where only some amateurs were involved. In those days, the  microprocessor was to invent and the Personal Computer only a faint dream : you had to design and build everything from the antenna to the display device.
My first approach was a dipole cut for 137 MHz driving a home made VHF FET converter which output was connected to a highly modified BC603 surplus 27-29 MHz receiver. The sub-carrier demodulation unit was a mixed tubes-transistors circuit driving the Z axis of an old oscilloscope. A camera took picture of the screen while the spot swept slowly from top to bottom.
After a lot of tests I was able to obtain first pictures during the summer of 1968 : their quality was not outstanding but it was really encouraging and fascinating to see, for the first time, the Earth with its continents, oceans and clouds.
Gradually improving the whole system I was pleased to receive pictures of really better quality.
These first results were presented in the French amateur radio magazine Radio REF (" Réception d'images via satellites météo" , Roland Cordesses, Radio REF, May 1969, pp 333-334 ).

A sample of  a received picture appears below :

This is a "mosaic" of several pictures received during 2 consecutive orbits in 1970. One can see Western, Northern and Central Europe as well as North Africa.

Everybody is now familiar with this kind of picture, quality of which is far better, but remember that in these days it was the result of an almost endless work.
 
 

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