Firstly, a few uses for two-way radios.
Remote activated noise maker. Sync two handhelds, hide one somewhere (in a field of traps?) Sneak into the opposite side of town, set off the noisemaker, distraction!
Radio Beacon. Will need a Large Aerial construction or something, as well as a few other mods. Ability to load multiple batteries into it. Use: A cross-survivor game effect. Your survivor dies? Have your new one craft a Radio Direction Finder (Radio plus two more antenna) and go hunting for your old stash!
Later on, it could be used as a NPC attractor or something.
Modular parts:
So, We should have a collection of parts with basic interactions. Radios. Timers. Tripwires. Pressure pads. They all have outputs (and in the case of radios and timers, inputs as well.) Most items would have a “push button” activation that could ALSO be done with electronic parts. Make a ignition, and turn your grenade into a long-time delay. Or a booby trap. With a fully modular system, the only limit would be your creativity.
With bits like this, you could connect a radio to a block of C4, and have a remote detonated bomb, or chain a radio and a pressure pad to alert you to things in your shelter. Add a timer to the Beacon above, set for 24 hours. Keep resetting it when you return, result? 24 hours or less after your death, your radio beacon switches on.
