GRA-4 ANTENNA PARTS
AN/GRA-4 ANTENNA SET PARTS. THE STANDARD SETS ARE 40 FOOT TALL.
GRA-4 HAS BEEN IN SERVICE SINCE 1951 AND MAY HAVE BEEN IN USE BEFORE THAT.
THERE HAVE BEEN A NUMBER OF MODIFICATIONS AND VERSIONS, BUT SOME PARTS HAVE REMAINED THE SAME THRU SEVERAL DECADES OF USE.
MAST SECTION AB-85 IS 3 FOOT LONG AND USES 16 SECTIONS IN ONE SET. Each of the 16 AB-85 sections adds 2-1/2 feet to the total height of the AB-86 mast.
MAST SECTION MS-44 IS 5 FOOT 6 INCHES LONG AND USES 8 SECTIONS IN ONE SET THAT IS CALLED AB-155. Each of the 8 MS-44 sections adds 5 feet to the total height of the AB-155 mast.
SOME MAST SECTIONS HAVE CONTACT FINGERS IN THE TUBE SO A GOOD RF CONTACT IS MADE FROM ONE SECTION TO ANOTHER AND THE ENTIRE MAST CAN BE USED AS AN ANTENNA. SOME SECTIONS DO NOT HAVE THE FINGERS AND THERE DOES NOT SEEM TO BE ANY NOMENCLATURE DIFFERENCE.
