Decoding NOAA Weather Satellites

Online radio forums often have postings of intriguing weather satellite images that hobbyists have received and decoded. I always wondered what was required to produce those images. This article explains what you need to know to produce these images yourself.

Two classes of weather satellites are available to decode. Geostationary satellites appear to stay in one place overhead and transmit their data to the ground in the 1.6-GHz range. Receiving these signals requires a dish antenna and a low-noise amplifier. The geostationary satellites available to decode will depend on where you live. Polar-orbiting satellites orbit the Earth approximately once every 100 minutes, transmitting their data to the ground in the 137-MHz range. Much simpler equipment is needed to receive and decode the data from these satellites. What follows is an explanation on how to receive and decode these polar orbiting satellites.

The Satellites

There are three polar orbiting weather satellites currently operated by the National Oceanic and Atmospheric Administration (NOAA): NOAA 15, NOAA 18, and NOAA 19. These three satellites spend their time taking images of the Earth and sending the data back down to the ground by transmitting an FM signal in the 137-MHz range. Table 1 lists details about these satellites:

These satellites are polar orbiting, meaning that their orbital path is over the North Pole and the South Pole. They have an orbital period of approximately 100 minutes, so they orbit the Earth between 14 and 15 times per day. The Earth rotates beneath the satellites as they orbit. That means that these satellites take images of the entire surface of the Earth each day, so you should be able to receive them no matter what your location is in the world.

A good way>. The site has a lot of good information about satellites. You will want to go to the Satellite Info >> Pass Predictions section.