If the British 1st Airborne Division had the proper crystals in their radios, they could have better coordinated with the rest of the Allied commands. Supplies meant for them that were dropping behind the German lines might have been redirected to the areas they held. Then they could have resisted or withdrawn (if necessary) more effectively. The Polish Parachute Brigade might have been spared their disaster.
As it was, the 1st Airborne couldn’t communicate with the rest of the commands in the operation due to the short range of their broadcast radios. This led to worry in the Allied staffs, miscues as supplies (and the Polish airborne troops) bound for them didn’t reach them, and poor coordination in effectively bringing the elements of the division together.
I liked Gene Hackman as the Pole in the movie.