Is the Spark using a radio technology for the RC - drone connection that's different in any way than conventional Wifi technology?  I don't understand how I can lose wireless Internet walking out to the sidewalk in front of my house,  but the drone can be flown out to 1-2 miles.  Are they using an unusual modulation technique that's not done on regular Wifi?

For Spark it's the same WiFi protocol. The difference is the transmitting power

It uses the enhanced WiFi protocol. Thank you for your attention.

WiFi is not RC technology.... it's a trademark.
IEEE 802.11 set of standards define MAC and PHY specifications for device interoperability.
PHY portion might eventually be considered RC technology. And yes, it's pretty much the same as in average WiFi router.