David wrote:

A signal generator is a piece of test equipment. It is not a
communications device.

For its normal use it's a piece of test equipment. But for the intended
experiment, it is the primary (and cheapest) way to send tones onto a
particular frequency to be recorded.

What happens when tones are sent to the frequency? Nothing. But in the
Mark IV experiments, they were a conduit for voices (allegedly
paranormal in nature) to materialize and a 2-way communication to take
place (versus the recording of white noise with a tape recorder, asking
questions, and having to stop the tape, play it back, and analyze it
with software, which most paranormal investigators realize is too
tedious and time-consuming and one-way in nature - more like email vs.
instant-messaging for paranormal communication).

grav