I don’t believe in smoke signals. I think it would take near-perfect conditions for “puffs” of smoke to be visible from any significant distance. Smoke usually dissipates pretty close to the ground. I don’t think that any “signals” (aside from smoke or no smoke" could be seen from far away. I’ve seen claims that Native Americans and Chinese cultures used smoke signals, and I understand that Boy Scouts were taught about them. I still can’t believe that smoke signals couls be any more effective than a flag on a fifty foot pole. Any thoughts or experience in the field?
This, at least, I can address. The Boy Scout Handbook has information on many different kinds of signalling, and we were taught several of them (including Morse code, Braille, and semaphore flags). But smoke signals are not mentioned at all.