>>4
If you want to transmit, there are not so many free frequencies, especially for transmitting data.
There's PMR443 and 2.4 GHz or 5 GHz (wifi, Zigbee..). The 900 MHz band that allows longer distance is only allocated to radio amateurs in Region 2 (in Europe it's used for mobile phones)
This is what I want to do:
https://www.youtube.com/watch?v=2TZGzXReN-U
https://www.youtube.com/watch?v=sHGUuGvB0pg
There's a seller on ebay who has ready-made device like the one used in that Berkeley course to connect a Baofeng radio to a computer: https://www.ebay.com/itm/EASY-DIGI-UV-5R-INTERFACE-for-laptops-and-desktops/323006664493