Some 8 years ago I posted some experiments using 2 Software Defined Radios slaved to a common clock. The idea was measure small thermal noise by making correlation measurements between the IQ samples from each radio. This is a project that has kinda smoldered in the background where I've made progress in fits and starts. Since most (all?) RA signals are small thermal signals it seemed like the technique should be a natural approach. A recent thread discussing the feasibility of using SDRs to...