History of NVIS

History of NVIS-

NVIS was first discovered or developed by the German Army in World War Two, while they were engaged with the Soviet Union on the Eastern Front. What they found was that while their excellent upper HF/lower VHF radios, developed during the late 1930s during the run-up to the solar peaks of Cycle 17 (1937 to 1939) worked very well for long haul HF communication, they had great difficulty using these radios for intermediate communication between groups or columns; their columns were often too far away for LOS communication and too close for HF skip. Amateur operators (Hams) today call that being in the “skip Zone.”

In modern technical terms, the F layer direct reflection frequency (FoF2) required for short range skip would have been too low for many of their radios. So the Germans started using a lower frequency radio originally intended for infantry use and created special horizontal dipole and loop antennas mounted on their vehicles to give their lower frequency signals maximum amplitude directly up. Here is a photograph of Heinz Guderian’s command vehicle showing a NVIS cage antenna. One can also see the extendable mast used for VHF in the center.

During D Day and again during the Vietnam War, the US military also had issues keeping in touch with various elements of their forces, especially in rugged highlands terrain. The answer was, again, NVIS, using low frequency low elevation horizontal antennas to maintain communications. Today, NVIS communication is practiced and used by military organizations and their affiliates, as well as various members of the preparedness community, to provide reliable, fast, and secure communications with lower probability of DF location.