The modern tools to have would be phones equipped with mesh networking and some solar powered chargers. There are a few nice things on the market for this that

The modern tools to have would be phones equipped with mesh networking and some solar powered chargers. There are a few nice things on the market for this that will charge your phone with just sunlight. Some phones also used to have radios built in; I recall Nokia had a few models with radios built in. Some might still have that. Otherwise, building radios from parts is not that hard and used to be a rite of passage for kids interested in tinkering with electronics. I remember playing with a kit when I was about 9 or 10. It would be interesting to learn what people on the ground in the Ukraine are doing that works.