[SeeSharp]

Not just radios but FM radios. The Germans had clear voice communications in every tank. For them it must have been like fighting against armies of blind men.

[Reagan Disciple]

The Russians didn't have comm until very late in the war. In 41-43 they just sent divisions out with orders. If the battle changed, they never did because they had no way of communicating nor could they stray from original orders.

If Hitler had listened to Guderian in the fall of 1941 that campaign would have ended strikingly different.