Articles
Weather Satellites
Introduction
Receiving images from weather satellites is a popular hobby followed by thousands of people throughout the World. The reason for this is relative ease with which a receiving system can be setup and the comparatively low cost of doing so. Generally, spectacular results are possible with just simple equipment.
There are two types of weather satellite system in use: geosynchronous (also referred to a geostantionary) and polar orbiting. The geosynchronous type is in equatorial orbit about 36000 km above the Earth's surface at exactly the same speed as the rotation of the Earth. For this reason, the satellite appears to be in the same position in the sky at all times. Polar orbiting satellites have a completely different trajectory which takes them in a much lower orbit (about 850 km) passing from pole to pole. As the polar satellite orbits, the Earth rotates under it so that from the ground the satellite appears to advance East to West with each pass. In this way the a single polar satellite can cover the entire surface of the Earth.
Polar
SatellitesGetting started
Perhaps surprisingly, you don't need to spend a great deal of money on equipment in order to get started receiving weather satellites. In some cases it is possible to cobble together a system using radio receiving equipment you already have. For example, I was able to receive and process the sample image in the polar satellites section of this article using a conventional AOR AR5000 receiver (which has the correct bandwidth), a 137 MHz crossed dipole and Chris Bock's popular freeware WXSAT software for decoding the signal and displaying it on a Windows PC.
There are many homebrew designs around and many cheap designs for VHF equipment for use with polar orbiting satellites. One of the best sources of information on equipment (both homebrew and commercial), techniques and weather satellite news is the journal of the Remote Imaging Group (RIG) which is mailed to members four times a year. There is also a column on weather satellites in Shortwave Magazine by Lawrence Harris who has his own website.
Timestep is an excellent source of commercial equipment for all the services available from both geosynchronous and polar orbiting satellites.
For more information on the Meteosat service, visit EUMETSAT's website.
More information can be found on the web for NOAA, the NOAA GOES geosynchronous satellites and polar orbiting satellites.
Weather Satellites | Polar Satellites | Geosynchronous Satellites
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Copyright © 2000 Simon Collings