If there is a randomness to the polarization of photons (Bell's Theorem) why radio signals hit the reciever in the same state they left the emitter? I have tried to understand Bell's Theorem (and I am still working on that) and I am probably missing something here, but a radio signal does not seem very random, rather the opposite. It seems very determined over its travelling distance. The signal in the emitter and the signal in the reciever must be the same to make this possible at all, and this should include polarization.
 A: Chiral Anomaly's answer talks about quantum limitations on the measurement of radio signals, but I think that's beside the point.
Bell's goal was to prove that no local hidden variable theory could reproduce all of the predictions of QM. To do that, he only had to give one example of an experiment whose results couldn't be explained by local hidden variables. His theorem is about that one specific experimental setup. It isn't a general result about quantum measurement, and doesn't apply to ordinary radio signals at all.
A: Chiral Anomaly wrote in his answer
An ordinary radio signal involves a huge number of photons

And not only this. As long as you accelerate the surface electrons of an arial all in the same direction they emit photons all with the electric field component parallel to the arial and the magnetic field component perpendicular to it. Taking two of the ariels, one perpendicular to the other and rotating them synchronously, you get the setup of entangled signals.
Accelerating electrons at the moment the ariels are in rest, one get two signals with a randomness for any receivers. The result of such an setup will in general be not different from the setup of the Spontaneous parametric down-conversion. Different is only the number of photons for each outcome. With ariels it is a stream of polarized photons, in the SPDC there are only two polarized photons.

The point with entangled photons in SDPC is that we can’t - at least at the moment - control the direction of polarization of the two photons. With the antennas we do it and to get the needed randomness for cryptography we need to rotate the antenna rods. But of course this doesn‘t works because in SPDC the measurement can be done only once while from the huge number of photons from each signal cycle it is possible to receive it with receivers with different oriented rods.
