Hi Ed, I think this problem is more a Microsoft issue with the latest definitions for defender. It seems that there are a lot of people having the issue with many different programs/apps that they have been using for quite a while. Hopefully the next round of updates from Microsoft will fix the issue.
I have been using SDRAngel on Win7 x64 Ultimate for many months without any major issues. Mainly just bugs in the app that are constantly being rectified by the developer. There is no need to install python etc. SDRAngel (on windows at least) is a completely stand alone app. No installation required apart from drivers for the SDR device that you are using (for example :- LimeSDR needs ZADIG drivers to be installed to make it work with SDRAngel).
On another note, the best place in this forum to ask about issues with SDRAngel is under the existing topic of “SDRAngel RX & TX”. It has a lot of people following it, including the developer himself.