garyka,
If we are talking about satellite reception and not over the air antenna reception for locals,here is a DTV spot beam map dated 06.
http://www.scottandmichelle.net/scott/dtv.html
There have been more spot beam areas/locals added since 06. This map will give you an idea of how it works. Lets say you live in the Denver area. As you can see it is a large coverage area. If you live in that area you probably get the Denver stations for your ABC,NBC,CBS,Fox,PBS and perhaps other channels thrown in. Lets say you travel out of that Denver spot beam foot print you will not be able to receive those channels from Denver or any of the other spot beams unless you call DTV and give a different address in one of those other spot beam foot print areas. This does not affect your billing address. You want to keep your billing address in most cases.
Others can probably give you more information about East and West Coast stations for your locals when full timing. Things seem to change all the time and sometimes a different story surfaces depending on who you talk to when you call DTV or Dish Network. JB