Interesting review. The 24 bit 4 MS/s ADC is not that expensive as I expected, Digikey sells it for $38.79. I wonder if you could just connect some long wire to it and then demodulate longwave AM radio broadcast signals, all digitally, without external filtering.
PS: Is it still Agilent or Keysight? Strange that if you click on the products link on the keysight.com homepage, it just links to agilent.com, with the same old Agilent Technologies logo. Looks like they are not really serious about the name change.