must consider the required circuit quality for the information to be passed. The farther the frequencies
are dispersed from the center or tuning frequency, the poorer the quality of the circuit. This is especially
true for sky wave transmission, since frequency affects the skip range. Even a small change in
frequency can alter the signal's path through the atmosphere. The frequency manager must determine
whether signal quality or anti-jam capability is more important when assigning frequency hopsets.
(a) High priority networks that pass critical voice or data information must be accurate.
Such networks must use hopsets restricted to a narrow distribution of frequencies.
(b) Networks that are subject to a high level of jamming require maximum dispersion of
frequencies in the hopset. The main drawback of wide dispersion is poor system quality due to the
lower radiated power from the antenna when the hops are on frequencies at the specified limits of the
bands.
(4) The NRI hopset scheme requires the use of only two hopsets throughout the corps area.
The hopsets are specified by the corps frequency manager, coordinated with the corps signal brigade,
and included in the SOI data transferred from the corps to all divisional elements. The remaining
hopping variables (TSK, net identifier, and time) are identical for the NRI networks. This permits
transient users to access the NRI system, using a single set position across the corps area.
(5) Cue and manual frequencies for SINCGARS networks are designated in the SOI for each
time period. The cue frequency is assigned to a 50 kHz channel to allow older generation and friendly
radio users access to the network. It is also limited to the VHF band from 30 MHz to 75.95 MHz. The
manual frequency should be assigned to 25-kHz channels from 30 MHz to 87.975 MHz. The BECS
computer automatically assigns both frequencies, along with a hopset using the above criteria. Table 1-
2 shows the hopset designation, the manual frequency, and the cue frequency for each time period. A
radio operator enters all three variables into the radio for each period. An operator uses the cue
frequency to enter a network in which he does not normally operate. The network uses the manual
frequency for internal network activation prior to transferring to the FH mode.
(6) Interference can occur in the single-channel nonhopping mode and the FH mode.
Planning includes provisions for interference between collocated radios of the same type (for example,
single-channel to single-channel radios). Single-channel frequency assignments must comply with the
standards for minimum antenna distance. The potential for interference increases as the total number of
collocated FH networks increases. For example, a brigade CP may operate in six different FH networks
at a time. The hopsets should maximize use of frequencies separate from any of the collocated
networks. This can be planned, but it requires knowing network structures and which networks are
collocated. The frequency manager works closely with the G3/S3 to minimize the effects of collocated
networks.
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