When I got my first rtlsdr dongle I spent hours just surfing the frequencies looking for interesting signals and trying to decide them. It's a great hobby!
SDR has opened up a new frontier for me, it gives me the same excitement I got when I discovered BBSs and then the internet.
I was lucky enough to have a project come up last year that required gsm/4G and GPS simulation. I got budget to buy a bladerf and a nice SBC and built a box that could simulate a GSM, 3G/4G basestation and simulate GPS.
That's awesome! Especially since your work experience seems to integrate with your hobby, and a very cool hobby at that.
Just to re-balance the universe a bit here, I almost stepped on my RTL-SDR the other day, in a neglected corner of my workspace, and felt pretty guilty about it ;-)
(Tangentially, I gave a cheap portable SW radio to my son the other day, after not using it for a while. I was trying to find a favorite FM radio station to demonstrate to him, and stumbled across one of the local emergency services instead, in the 150 MHz range. Haha, no wonder the dial markings don't match up at all. Now he's telling me what kind of makes & models he's hearing about over the air...)
