Which was happening from that radar station in Pennsylvania as was indicated in the link I previously submitted.
Beyond that, I do not think it is too technically difficult for anyone to ping it if they want to. It's made to automatically respond to the correct sort of query on the correct frequency of microwave radiation. You could design a missile so that the missile will continuously ping it.
It would be effectively guiding the missile to itself. That would actually be a pretty easy guidance system to build.
Flight TWA-800 at 13,800 feet was visible by the naked eye at 8:31 PM on that July evening from the range this theoretical missile could be fired. It was at the extreme altitude range that could be reached by some tripod launched missiles, but not by any shoulder launched missiles.
If I remember correctly, Jack Cashill said it was bigger than a shoulder fired missile. If you have it mounted on a large boat, it likely can have a pretty good reach.
True. About two to three weeks before the TWA-800 disaster, a fully loaded and ready tripod mounted missile was discovered by a county sheriff's unit set up on a dirt road about four miles from the airport that TWA-800 took off from. It was armed and ready to go. It had a missile in the launcher, ready to go. . . Just no one there to launch it.
They explain it away. . . by giving no explanation of where it came from or why it was there. I guess it was just road-side litter. Such a launcher missile combination was easily worth over a million dollars on the underground market at the time, but it was abandoned on the road-side for some unknown reason.
As for using a radar to ping the plane, such a guidance would have lit up every receiving radar antenna in the area while it was doing it. . . and the number of return pings from TWA-800 would have been a dead giveaway that something was up. Instead we have only the official return pings from the transponder ever 4.64 seconds.