It's been awhile but just this week i noticed an interesting project on Github referencing NMT base station, and today i probably made the first proper phone call on NMT service in this country since service shut down! It is software solution for operating A, B and C-Netz, NMT and even AMPS basestation at home. It requires two radios with ability to transmit and receive on the correct frequencies. It is part of "Osmocom" project, Open source mobile communication as it stands for.
https://osmocom.org/projects/osmocom-analog
http://git.osmocom.org/osmocom-analog/
It runs on a Linux based system with two soundcards for speech back and fourth.
All credit goes to Andreas Eversberg and rest of people behind Osmocom for making this happen!
Short test: https://youtu.be/Zjz9EAR9j_k