[nevergiveup]

You need a form of matched filter but that's software. You use a pseudo random code to encode the signal and at the other end a matched filter

I used truly random noise and a little hardware. No software or careful filtering needed.

[pepsi_junkie]

I used truly random noise

If it's pseudo random, both sides can generate the same sequence and thus stay synchronized. How do you randomly encode the signal (really randomly) and get it back? If it is true random data, by definition it would be impossible for both sender and receiver to have the same sequence. I suppose you could use truly random data to encode a signal for recording as a rudimentary form of encryption as long as you saved the random sequence to later reconstruct (as the key) but I dont know how you could do it in a comms system unless perhaps you use static random data which each side has recorded.