What a great detailed response! Thanks.
I had already discovered the engineering mode but didn't know how to interpret the UARFCN number, though I suspected that was the key. The ARFCN I was able to interpret from the chart on this page that I found from searching: http://gsmfordummies.com/intro/intro.shtml
My numbers are in the 850 mhz range, but that's only when the network mode is set to 2g.
On 3g, the AFRCN changes to 0, and the UARFCN value becomes the one to watch. My number is either 512 or 4385. Reading from your post, apparently I'm switching between the two frequencies.
Interestingly the RSSI values, which I'm interpreting as signal strength are lower for 3G (around -100), than for 2G (in the -85 range), but voice quality and call stability are better in 3g even with the lower signal strength.
I'm thinking of building this coffee can antenna as an experiment, which works at 1900 mhz.
I have no idea how to change the dimensions in order to build an 850 mhz one. The video is good, but unfortunately there's no technical information presented. But since I can get 1900 some of the time, I can see if the can antenna boosts the signal a bit.
Thanks for the camera button turn off. Previously I couldn't find a way to close the the engineering mode window other than turning off the phone.