Well that would be the easiest solution. But it seems that if anyone is using a Stingray type SDR to periodically read my SIM card metadata, it seems that if they found a new phone in the vicinity they would get that one too.
There are so many secure phone apps and companies, it seems there would be one that did encrypted VOIP from my phone to their server, and then unencrypted POTS to the remote party. After spending an hour sifting through several websites, which are mostly uninformative marketing wank, and trying to determine how their system worked and if it met my requirements, I was hoping to find someone who is already familiar with what is out there. I don't want anyone to do my research for me, but posted just in case there was someone who already knew.