TM 11-5895-1412-12&P
c.
FREQUENCY TYPES
1.
FIXED FREQUENCY
Fixed frequencies are frequency values that are usually assigned to non-
tactical nets.
The frequency value is manually assigned and is unique to the
specific net.
The frequency value is non-changing for all time periods of the
generation.
For example, the MEDEVAC net may be assigned 34.000 MHz and will
never change.
Also, 34.000 MHz will not be assigned to another net. Fixed
frequencies do not have any restrictions assigned and are used on single
channel nets only.
2. RESTRICTED FREQUENCY
Restricted Frequencies are frequencies that can not be used by certain nets
for various reasons (e.g. power, area restricted). The frequency value is
assigned a letter restriction and if a net has the same restriction letter
assigned to it, then the net will never be assigned the frequency value for
any time period.
Restricted frequencies can be either discrete or common user
frequencies.
The BGU Frequency Assignment Program (BECS software) is designed to recognize
up to 16 separate frequency restrictions (identified by a letter code) per
frequency band.
As each restriction is identified, assign it an appropriate
letter code (A-P) and explanation sheet.
Multiple frequencies can be assigned
to a single frequency restriction letter.
The BECS software is designed to recognize up to 8 of the 16 separate net
restrictions (identified by a letter code) per net. As each restriction is
identified, assign it an appropriate letter code (A-P) and add the code and
restriction description to an explanation sheet.
These same frequency restrictions will be used at a later time with specific
radio nets on the master net list.
When assigning frequencies, nets and
frequencies with the same restriction letter code CANNOT be matched together.
A “reverse logic” is used when assigning restrictions.
For example, the
letter “A” may be assigned to frequencies that will not be used to communicate
with aircraft (frequency restriction).
The letter “A” should then be assigned
to nets that must communicate with aircraft (net restriction). Therefore “A”
restricted frequencies will not be assigned nets that have been assigned the
“A” restriction.
When a BECS Spectrum Manager receives the Radio Frequency Allocation (RFA), he
is required to read and interpret it, extract both external and internal
frequency restrictions, complete a
restriction explanation sheet and compare
frequency restrictions against nets when completing the master net list.
Remember you have 16 restrictions per frequency band; the restrictions, letter
coded (A-P), do not have to be the same for each band.
d. FREQUENCY ASSIGNMENTS
Ideally, frequencies are randomly assigned to nets designed to receive a
changing frequency with each change in time period. However, because of
special cases (e.g. MEDEVAC) and the lack of available frequencies and
abundance of needed nets some nets must share frequencies or reuse
frequencies.
Also, some nets require frequency separation from other nets to
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