I have a RA-17L, and was looking for the BNC type connectors for it. I've been told they are British military type connectors similar to a BNC connector. They are the screw on type. They are the connectors which plug into the 1Mhz. and RF output on the rear of the receiver, and some of the ones on the main chassis for instance. Thanks very much, Albert Santangelo VE3 AJM