One of the key requirements for getting a patent is that the invention must be novel. So indeed, their work is novel; it's just not of any importance at all. It is a Rub Goldberg mechanical mechanism. To understand this, you need to focus on the invention as defined by the granted claims, not on whatever prior art may be disclosed in the patent's specification (the wordy bulk of most patents).
To me, the interesting question is, were they the first to come up with the concept of communicating while jumping around on a random-like sequence of frequencies. What was the prior art?
