a. The command operations FM net is used for C2. The G3/S3 operations serves as the net
control station (NCS), and the nets stations represent the units conducting combat, CS, and CSS
b. The intelligence FM net is used to pass information concerning enemy forces and intentions.
c. The rear operations center FM net is used for defending the rear area. The base operations
radios of the several clusters of bases, the base defense liaison teams, the military police and other
reaction forces, and field artillery and aviation brigade elements are this net. Some units moving
through the area (reserves or reconstituting forces) enter this net in case they may be given a short
duration tactical mission (change of operational control) to eliminate an enemy threat. Other units enter
the net to receive immediate intelligence on developing threats in the rear.
d. IHFR is the primary radio system used in the HF networks. The HF-amplitude modulation
(HF-AM) networks shown are generic networks. Specific networks and subscribers depend on local
guidance and requirements.
(1) HF networks are similar to the VHF-FM networks in function and establishment, and
many are backup or supplemental to their VHF-FM counterparts. HF networks are established when
unit dispersal exceeds the planning range for VHF-FM systems. HF radios, when used with standard
vertical (whip) antennas, produce surface waves that travel farther than VHF signals. They do so
because of the lower frequencies used (2 to 30 versus 30 to 88 MHz). The main reason for the range
difference is the reduced energy absorption effects of ground and terrain features at the lower HF
frequencies. Standard vehicular HF radios also have higher power transmitters (100 watts to 400 watts)
than VHF radios, which increase ground range, compared to SINCGARS or MSE. HF radios use an
NVIS antenna to transmit by sky wave propagation. This transmission mode takes advantage of the
phenomenon that the radio wave is reflected back by the ionosphere in a circular pattern that covers a
circle up to 400 miles in radius. Transmitter power levels of 20 watts to 50 watts are sufficient for
(2) Logistics units use HF radios for C2 and internal coordination due to the distances from
the division support area to the brigade support areas. The HF net backs up the FM net when the
division's tactical spread extends the lines of communications. When available, the ACUS replaces this
net, as well as similar corps nets. Corps support units establish similar networks or monitor the division
networks to ensure push-forward support.
Signal brigade/battalion CNR operations. These CNR operations are conducted in six networks
which provide the signal commander a means to communicate C2 information and engineer signal