Many folks, me included, put our phones in Airplane mode while at home and make/receive calls over WiFi. However, satellite internet service usually has high latency which won’t work well with VoIP (Republic’s service is VoIP). You can test your connection’s latency (ping) at Speedtest.net, or a variety of other internet speed testing sites. Ideally, you want no more than double-digit latency (measured in milliseconds). Unless it has improved dramatically in the past couple of years, satellite latency, at least in my experience, tends to run in the 500-700ms range, at best. That just won’t work with VoIP.
Republic Wireless partners with both Sprint and T-mobile. If you are in an area with a serviceable signal from either carrier, you shouldn’t need WiFi for calling purposes, but can still use it for data purposes.