"Thierry" - wrote in message ...
Hi,

I need to now before buying a receive + antenna set if there are always on
orbit around earth geostationnary or polar satellites transmitting weather
images in analog mode or all are now transmitting in digital mode ?

thanks
Thierry

Hi Thierry

I dont know enough about "mode" terminology to answer your question about
"analog" or "digital". I have been actively involved with trying to build
an antenna for receiving signals from NOAA polar orbiting satellites at 137
MHz and from AMC-4 geostationary satellite.at 4 GHz.
I assume you refer to your buying a Receiver when you wrote Receive.
The images from the polar orbiting NOAA satellites are sent down at both
137 MHZ and at 1.7 GHz. The 1.7 MHz signals require a high gain antenna
that needs to track the satellite.

The GOES, S band and the POES HRPT, L band systems cost thousands of
dollars since they include high gain antennas. If you are thinking about
spending thousands on a "receiver + antenna" I think you would already be
well informed about what to buy. I'll assume you are considering buying an
antenna and receiver for 137 APT image reception.

I recommend the R2FX receiver http://www.geo-web.org.uk/shop.html for
137 MHz imaging. It is designed to receive FM signals. Any 137 MHz FM
receiver will work for receiving APT images in the 137 MHz band, but very
few will provide adequate signal to produce good images.
The Quad Helix is considered to be the ideal APT antenna. Dartcom
http://www.geo-web.org.uk/shop.html has high quality Quad Helix antennas
for sale at about $350.00.

If you have interest in building your own antenna for 137 MHz APT imaging,
I can show you how to build one that performs better than a Quad Helix.for
less than $20.00.

Jerry KD6JDJ