So I came across this service provider, https://republicwireless.com/ who's set up utilizes wireless whenever possible.
Now the first thing that occurs to me is "how secure is this?"
Does anyone have any experience with wifi cell phones (or know anything about the security measures that may exist)?
I think you meant to say "WiFi" rather than "wireless"…after all "traditional" cell phone calls are also "wireless".
It sounds like they try to default to using a VOIP (voice over IP) connection over WiFi…and they might even still use VOIP even when they are forced to use a cell tower rather than WiFi. In theory, at some point in the future, all "cell" companies might go to essentially using VOIP (i.e. completely kill off their so-call "cell calling" network and just have a "data" network only).
As to how secure it is…
The security of WiFi will at least somewhat dictated by whether the WiFi network you are using is a "protected" network (i.e. requires a WEP, WPA, or WPA2 password). There is a reasonable chance that they also then encrypt the call at the phone and unencrypt it somewhere at their server end, but I could not find anything definitive on that subject on their website. The best that I could find is this thread in their forums…it has links to other discussions:https://community.republicwireless.com/thread/18817
As I understand, however, most VOIP call data packets (that is essentially what VOIP does…turn your call into an audio "file" that get sent over the Internet as data packets) are not encrypted. So, in theory, one can "listen" into VOIP calls if you can intercept the packets. That is where it gets tough. Unless the person is essentially locally on your own local network (i.e. basically able to intercept your WiFi traffic or similar), it becomes tough to intercept a specific call from a specific person to another specific person. It is relatively easy to intercept data packets out there on the Internet, but those would be random calls. That is like me telling you that I want you to listen to some guy named John Doe have a face to face conversation with another person Jane Doe at some coffee shop out in the world but I don't tell you where John Doe or Jane Doe live or where the coffee shop is located in the world…in other words, you would have to randomly pick some coffee shop and hope that John and Jane are there having their conversation. To a large degree, that is kind of the what it would be like trying to intercept a VOIP call out on the Internet.
So, in the end, it is likely no more or no less secure than any other VOIP service such as Vonage, MagicJack, any cable company's voice/phone service, etc.