SurCom represents a number of companies from the United States that sell radio equipment in the military frequency bands HF (2-30 MHz), VHF (30-90 MHz) and UHF (225-400 MHz). With these frequencies, line-of-sight and beyond-line-of-sight connections can be built up. In general it can be stated that the lower the frequency, the longer the distance that can be bridged. But also, the lower the frequency, the lower the amount of data that can be sent. Depending on the need, a connection device is chosen in one of the tiers. In a network environment, the system now often determines which path is chosen and makes it clear to the user. In addition to radio equipment in these specific frequency bands, the product catalog also contains information about systems that operate multiple bands and radios suitable for Search and Rescue purposes, which use both military and civilian frequency bands. Very different is Troposcatter. A connection where a broadcast is made that is aimed at the lower air layers, collides with it, scatters and can be received. The strength of the signal can be determined with a high degree of certainty by using mathematical models.
