Freerunner test

[Mike Montour]

Kevin Dean wrote:

> I'd like to reconfirm this before reporting, or at least kill my
> theory before reporting on it and creating a false lead. It seems that
> the SIM itself is important.

Two likely factors affecting GSM buzz are: which band it's using (850 or 
1900), and the transmitted signal strength (how far it is from the 
tower). If you had SIMs from different carriers I could easily see these 
factors being different. I can't think of a reason that two SIMs from 
the same carrier would differ, except for randomness in which tower it 
happened to use.

It looks like one of the 'Engineering Mode' AT commands can at least 
report which band you're on and the base-station ID. There is also a 
"transmit power" field listed, but when I tested it a minute ago it was 
always 0.

http://wiki.openmoko.org/wiki/GTA01_gsm_modem#Serving_Cell_Information_.282.2C1.29

I have a cheap microwave-oven leakage tester from Radio Shack, and I was 
able to put that next to my Neo to get a relative indication of its 
transmit strength. I could hear the level of the buzz go down at the 
same time that the needle on the meter went down.