catching signal from abroad 90 km away from the border?

I guess anything's possible when a radio wave skips. I remember when I was on a regional plan I once was able to make a call on my home network about 50 miles from the nearest tower. That was in the old analog days though. I doubt that can be done with digital. This may explain why you could see the network, but not be able to log on.

 

I had a similar situation happen to me, when I was getting Alltel SIDs from 50 - 100 miles away from me,
very highly unusual, but radio stations were doing the same thing as well, which is more common here.

See this thread:

Cell Phone Signal DX'ing - Wireless Advisor

I was going to goto Lake Placid someday soon, and do some field testing atop Whiteface Mountain
to see if I could get CDMA signals & SIDs from Canada, about 45 miles north of there...

 

Barciurek,

If you like this sort of UHF distant reception, it's one of many fields in amateur radio (radiosport). You couldn't register on the distant GSM systems because you were further than 35 km from the sites, more than Timing Advance could allow for.

COtech