help to detect the mobile

elsalam 3alykom-->(i hope peace for all)

i need help to know how can i detect the mobile (cell phone) waves going out & in from it at its steady state ,i mean not calling a number.

i know that in GSM it sends and recieves waves with the central to know if it has any callings or messages.

PLZ I NEED ANY THING USEFUL.

i want to start

thanks alot

You can use a crystal set type receiver near the unit. The pulse output pattern will tell you what state it is in. For simplicity, put a small speaker on the output and listen to the pulse pattern.

what about a LNA+BPF+video detector. BPF tuned to the mobile TX frequency. However this will only indicate mobile -> base station signal, not the other way round...