Does anyone know their usual distance from Earth’s surface?
Thanks. 
They are in geo stationary orbit, That’s at about 22,000 miles.
Not all satellites are in geosynchronous orbit. Satellites that a consumer mounted dish is to be aimed at are (satellite TV, etc). Low Earth Orbit (LEO - about 100 to 500 miles - it varies somewhat from different sources) is employed for a lot of telecommunications services such as mobile phone - you can have stations which track the satellites, it doesn’t take as much power to get a signal up to the LEO satellite, and you have less lag time to cope with.
Here’s a table of orbital distances and their uses:
In fact, if you want to dig through a mountain of data on the satellite “constellations” for various services, here’s a registry somebody maintains:
http://www.ee.surrey.ac.uk/Personal/L.Wood/constellations/
There’s an interesting picture on the “overview” page, illustrating the orbital heights of some of the services:
http://www.ee.surrey.ac.uk/Personal/L.Wood/constellations/overview.html
The CelesTrak site has information on the orbits of specific satellites.
The J-Track site plots the positions of lots of satellites, with orbits and ground tracks.
yabob’s first link is inaccurate in at least one detail: geostationary and geosynchronous are not the same thing. The former is a sub-class of the latter. Geosynchronous orbits are ones in which an object remains over a single longtitude of the earth, but it might vary in latitude. A geostationary orbit is a geosynchronous orbit directly over the equator, so that the latitude never changes.