While it's technically possible to get signal into the country, the larger problem is that people using it can more easily get in trouble if it's prohibited.
Radio receivers are passive devices. They do emit a small amount of RF, but it's limited and easily shielded. Worst case, you can build a completely passive receiver like a crystal radio. (NB for the EE pedantics: yes, I know I'm simplifying. I don't mean passive vs. active as in component definitions; I mean intentional vs unintentional radiators)
WiFi and other networking technologies are active transmitters and are quite easily detected. The same tech that's used to sniff out unsecured hotspots can be used to detect "dissidents connected to the internet."
Comments
While it's technically possible to get signal into the country, the larger problem is that people using it can more easily get in trouble if it's prohibited.
Radio receivers are passive devices. They do emit a small amount of RF, but it's limited and easily shielded. Worst case, you can build a completely passive receiver like a crystal radio. (NB for the EE pedantics: yes, I know I'm simplifying. I don't mean passive vs. active as in component definitions; I mean intentional vs unintentional radiators)
WiFi and other networking technologies are active transmitters and are quite easily detected. The same tech that's used to sniff out unsecured hotspots can be used to detect "dissidents connected to the internet."