A few more questions for the experts

[Viking]

If they, the Germans, had the gear to tune in to the British frequencies and use the direction finding antennas to give a bearing to the source what would that tell them?
British fighters over England!

And how hard was that to anticipate?

Regards

Viking

[Crumpp]

Actually it is harder in reality than you might think.

Airplanes have a finite amount of fuel with which to find the enemy and fight.

It was very possible to fool the defenses the slip in with little to no opposition. This is why decoy raids and radio traffic deceptions where run.