How Norway and French radios could change the early war

What small change could most easily alter the course of the European war?

A failed German landing in Norway or reliable French tactical radios could change the 1940 campaigns before later events become fixed.

The Norway counterfactual has the Royal Navy already at sea on its planned operations when German invasion forces sail. If that prevents the central and northern landings, northern Norwegian troops could move south, receive support in central Norway, and join forces farther south. German losses among cruisers and destroyers would add to the failed landing's effects. A French invasion during Germany's campaign in Poland is raised separately, but inadequate radios would still complicate it. Improving French army radios is proposed as another change with substantial effects in war games.