Passive Cell ID Logging - GSM

Hey i would like to log Cell ID s of GSM by an Antenna in combination with arduino.

Do you have any experience or suggestions which antenna i might use with arduino?
yea i know the signal is crypted but have you ever "played" with that signal? have you been able to get the cell ids without decrypting it?

I dont wanna send any test messages or do any calls ... Just the number of the Cell ID which i cross without using a sim card

best regards

iam thankful for any reply