Just for anyone wondering why Radio 4 in particular - it’s the only BBC station we have on Longwave (198? kHz), so you get over-the-horizon service from a singl

Just for anyone wondering why Radio 4 in particular - it’s the only BBC station we have on Longwave (198? kHz), so you get over-the-horizon service from a single tower. (which is why carries the shipping forecast, and why it’s of particular interest to submarines in the Atlantic too). So using it as a “sign of civilization” (one of multiple) sounds quaint, but with a perfectly logical reason behind it.