REL #34 CMU200 testing a GSM phone

After several episodes on using the CMU as a general-purpose instrument, I now explore what the device was originally designed for: mobile communications testing. I set up a call with a GSM phone, exchange GSM messages, and explore the RF and IQ signals.

00:00 Introduction
02:28 Getting a test SIM card
04:52 Crash course GSM physical layer
Field test:
07:30 Identifying unused frequencies
10:42 Setting up the CMU
20:22 A call with a mobile phone
20:26 IQ signals of uplink and downlink
22:32 Phone info, measurements, power envelope, spectral power
24:20 Sending and receiving SMS messages
25:58 Deeper investigation burst via IQ signal
27:46 Change MS time slot, hopping mode
30:04 Sending a custom SMS message
31:41 Final words