HELP Required to identify this.

NEW 18th September 2008

Unusual three-lug co-axial connector as found on military UHF/Microwave aerials and
systems. Also used on PTARMIGAN radio vehicles. Can anyone put a name or type
to this connector, and maybe tell me where I can get some plugs to fit these sockets?

As you can see from the pictures below, it's a fair bit larger than an N-Type socket.

See also the link on the projects page for the band 3 feed unit. It uses the same connector.