Satellite data collection without a permanent antenna requires some planning. I usually find when the best passes are for the week, and see if I have free time in my schedule to run out and collect data. Programs like gPredict and websites like https://satnogs.org/, or apps like Heavens Above can use TLE data to calculate when the satellites are going to pass overhead.

TLE or Two Line Element data is a format for describing the orbits of satellites. NASA and NORAD developed a data format in the 70s to describe the orbits of satellites that can fit on a punch card. Long gone are punch cards, but the TLE format is still used today.

The National Oceanic and Atmospheric Administration (NOAA) has been imaging Earth with satellites since 1975. These satellites are used to monitor weather patterns, climate change, and natural disasters. The data is transmitted to Earth in real time from these satellites, and can be received by anyone in the signal path.

In this post I will be collecting and displaying telemetry from the NOAA 18 satellite. The NOAA 18 satellite is in a polar orbit, meaning it orbits over the north and south pole. It takes images of the earth, and imediately transmits the image at a rate of 360 lines per minute. The data from this satellite is transmitted at 137.9125 MHz with Analog picture transmission APT.