About to buy a SDR for running cdma/gsm in my own home.

I’m in America. Hobbyist for old devices. Since 2G’s shutting down, I’m getting one.Anything I should know before I buy?
(Yes, I know about American FCC, but I plan on transmitting within inches of my table, not causing interference or taking up spectrum.)

Otherwise I need to be educated on what I am doing with this decision.