Dennis Ferguson wrote:

> What I've never quite understood is why AT&T never got around to
> adding GSM to those towers (there was another AMPS-only site in
> 94020 which seems to be gone too), though the fact that no competing
> carrier ever extended service into those places may say something
> about the economics of building and maintaining facilities in those
> particular locations.

I'm pretty sure that the AMPS coverage in the Marin Headlands came from
outside the area, either from San Francisco or Sausalito. Either the
Park Service (and prior to them, the military) wouldn't allow the
carriers to put towers out in the headlands, or the carriers didn't want to.

It's a pretty busy place out there now, with a lot of organizations
taking over the former military buildings, so I think the carriers would
want to cover it. It's certainly not a wilderness area, and there are
lots of structures out there a lot more intrusive than a cellular tower.
We visited the restored Nike missile site which was pretty cool, and
they've brought back some old missiles and have the elevator and the
thing that raises the missiles operational.