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Finding My Footprint

Members of the ISP-Satellite list discuss a simple question about satellites: How to find the area they cover (known as a footprint). As with many simple questions, there is not a simple answer.

[March 14, 2001]

On the ISP-Satellite list in February, MD inquired,

"Is there a service available that can tell you what satellites have footprints covering a specific location?"

GK warned that care has to be taken in gathering such information:

"I have found that many advertised footprints do not match the technical reality. They seem to be more an indication of the intended market for a service rather than the real footprint."

Others offered some links, but suggested further research:

[MP noted] "LyngSat has this."

[SB added] "SatcoDX gives you this information in many languages—but the best footprint maps are obtained direct from the space segment operators, and even these are usually at best a relative indicator of the Effective Isotropic Radiated Power (EIRP) and signal-to-noise (G/T) contours of the bird in question. You can use them for link budgeting, and you should find some other customers on the satellite and get their experiences.

It's always best to err on the side of a larger aperture antenna, cooler Low Noise Amplifier (LNA), and higher power amplifier, since circuits always seem to grow."

[DB agreed] "The footprint maps on the Internet are only marketing tools. They are worthless for any serious link budgets. How about a space segment broker? Best to find out what is really available out there—not only from the satellite companies, but also from the companies that have bought too much and either have packages for resale or are simply going belly up."

—End