With the Hemisphere S321+ GSM Cell Antenna, you can use your Hemisphere S321+ as a network rover. With most major carriers supported, simply screw in the GSM Cell Antenna and start surveying. There is no need for a costly external base radio setup, everything is contained within a cell network. As long as cell coverage exists you can use the Hemisphere S321+ as a network rover. This includes our own StormCaster Internet RTK. StormCaster works by using a cellular network to broadcast corrections rather than traditional UHF radios. Using this method, you can theoretically survey over an unlimited range. There is no need to be constrained by the limits of your internal radios anymore. Everything is in reach while using StomCaster with the Hemisphere S321+.