VHF Narrowband Relay for LOS Extension

The Marine Corps has frequent requirements for beyond-line-of-sight communications for voice and narrowband data in challenging terrains that normally limit or truncate links. The Naval Research Laboratory has developed a two-channel narrowband VHF relay that supports narrowband communications using standard Marine Corps radios. This relay is lightweight and designed to be borne aloft at altitudes above 65, 000 ft., providing connectivity to nodes as far as 150 nmi from the relay payload. This paper documents the design and the operation of the balloon-borne VHF relay, dubbed "Surrogate TACSAT", and details results from testing conducted out of Yuma Proving Ground in March of 2014.