Bandwidth?
"other techniques designed to increase the bandwidth of transmissions"
The limiting factor is most likely to be the available SNR as that places an ultimate limit on the data rate (Shannon limit).
If the PCs/controllers are well designed then RF leakage should be very small, and if you are relying on operations in the low tens of MHz region then background noise in most areas will already be way above the receiver's noise figure. So unless you are *really* close I doubt you could get more than tens of bits per second out.
Biting the hand that feeds IT
