Just after I put together the post on Visual Teaching - GPS Satellite Constellations I came across a site that displays live satellite tracking on a map:
The site allows you to track particular satellites, or view satellites that are in your particular bit of sky...
Even if a satellite is in line of sight with your location, however, it doesn't necessarily mean that you can get a signal from it. Many of the antennae on a satellite are directional. The rather wonderful SatBeams website shows actual satellite coverage maps for a selected satellite:
Where does SatBeams claim to get its data from? Is this a trusted source? Does the satellite tracking data site offer any explanation of where it gets its data from, and if so, how does this compare with the SatBeams site?
How can visitors to the Satbeams site particpate by contributing data back to it? In what ways might this user contributed data add value to the site or detract from it?
As well as satellite locations, it's also possible to find locations for other transmitters. For example, here's a geo-referenced list of UK television and radio transmitters.
(If you come across any related lists, such as a list of UK mobile phone cell masts, please post a link in a comment to this post:-)