I’m sure you’ve heard the typical ‘GSM sound’ on an FM radio by chance when a phone call comes in and the phone was close to a radio. It doesn’t happen that much anymore of course, as devices are mostly camping on LTE and 5G networks these days. But if you manually select GSM, you can still hear it today. So I was wondering if I could also ‘hear’ Iridium uplink transmissions of my Garmin InReach Mini 2 on the radio?
Turns out that it is indeed possible. Since a lot of Iridium seems to be taken from GSM, I was expecting it to sound quite similar. But it doesn’t. Transmitting a message takes around 2 seconds, and as shown in the picture above, the signal is quite audible, but doesn’t have the typical GSM rhythm. Anyway, the main takeaway for me is that one can ‘hear’ Iridium, and it confirms my assumptions that transferring the message just takes a second or two.