Racal Instruments AN/TRC-207, Operation And Maintenance Instructions

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TO 31R2-2TRC207-1
4-7
Section II. OPERATING INSTRUCTIONS
NOTE
Be aware that while performing the initial power-up and diplexer tuning procedures, the bi-
directional repeater will radiate RF energy that can cause frequency interference. Do not perform
this procedure before the frequency use authorization is obtained and in effect.
4-3 OPERATING MODES AND FREQUENCY RECOMMENDATIONS
This paragraph describes the different modes of operation available with the BDR and provides recommendations for
frequency selection to obtain optimum results in each mode.
4-3.1 Operating Modes
There are four different BDR operating modes, described in the following paragraphs.
4-3.1.1 Tactical Repeater Mode.
In this mode, the BDR operates in the same fashion as the basic Tactical Repeater (AN/TRC-199). It can provide one-way
extended range linking of one simplex communications net (in which the radios are set to transmit and receive on the same
frequency) with another simplex net (see Table 4-6), or limited two-way extended range of a half-duplex net (in which
the radios transmit and receive on different frequencies) (see Table 4-7).
4-3.1.2 Standalone Bi-directional Repeater.
One BDR can provide full two-way extended range to a simplex communications net (see Table 4-8). It can be used to
link two simplex nets such that they operate as one communications net, even though the radios in the two nets are
operating on different frequencies.
4-3.1.3 Tandemed Bi-directional Repeater.
Two or three BDRs can be set up in series (tandemed) to provide two-way communications over a greatly extended range
(see Table 4-9). When multiple repeaters are used, user radios may operate on any of the frequencies used in the series
(that are within line-of-sight range). For example, users in between two BDRs are able to communicate to users at either
or both ends of the chain, depending on the frequency selected.
4-3.1.4 COMMS Mode.
In COMMS mode, the BDR can be used to transmit and receive (unencrypted) radio traffic and to monitor (unencrypted)
through traffic on the communications net. This can be done using either Radio A or B.
4-3.2 Frequency Recommendations
General frequency recommendations are shown in the following tables. The basic communications set-up is a Base
Station communicating through a BDR to one or more remote handheld radios (HHRs). The frequencies shown in each
table (F
1
, F
2
, F
3
) are frequencies within one band that satisfy the separation requirement described below. A critical
requirement in determining specific frequencies to be used is that the radio A frequency and the radio B frequency must
be separated by at least 4 MHz or 3 percent of the carrier frequency, whichever is greater. Examples of the required
separation are:
Frequency A: 30 MHz Frequency B: at least 34 MHz
Frequency A: 88 MHz Frequency B: no more than 84 MHz
Frequency A: 136 MHz Frequency B: at least 140 MHz
Frequency A: 174 MHz Frequency B: no more than 168.75 MHz
Frequency A: 403 MHz Frequency B: at least 415.1 MHz
Frequency A: 470 MHz Frequency B: no more than 455.9 MHz