Hey, Darry -
There is a steel cable that resides in a perpendicular channel across the runway. This cable is there to literally stop the F16s in the event of an aborted takeoff or problems on the landing roll. This cable is elevated up out of the channel when there are F16 operations (departures or arrivals). I don't know how high the cable is elevated but I would suspect perhaps a foot or so above the runway. Think of this cable as somewhat similar in concept to what you see on aircraft carriers.
There is a cable that crosses each end of the the main runway, located about 2,000 to 2,500 feet from the end.
You will also hear "barrier maintenance" as a callsign a lot when the ground frequency comes in on the feed. This is the group responsible for inspecting the cable to be sure it is fully operational. They drive a truck from the guard base onto the taxiways and eventually to the point on the runway where the mechanical housing is for these cables, adjacent to the runway at each end.
As far as the communications are concerned, the F16s talk on a UHF frequency that is not scrambled. In the beginning of the feed I had tried to scan the frequency but the quality was too poor (presumably due to my 9 miles from the airport) so I had to abandon it. If I ever get the feed relocated up to the airport I may try to add these frequencies back in.
All SYR VHF frequencies you hear on the SYR feed have a counterpart in UHF for the F16s, which is why you hear the controllers talking but not the F16 pilots responding.