Racal Instruments AN/TRC-207, Operation And Maintenance Instructions, Page: 50 / 102

TO 31R2-2TRC207-1
5-2
The amplifier can function over the entire frequency range of 30-470 MHz, with transceiver operation only in the 30-88,
136-174, and 403-470 MHz frequency bands.
Figure 5-1. Bi-directional Repeater System, Functional Block Diagram
5-2.7 RF Matrix CCA (A1A7)
The RF Matrix CCA (A1A7) provides the mechanism by which the BDR can either receive or transmit through either one
of the installed receiver-transmitters. When one receiver-transmitter lifts squelch (receives a valid voice or data signal),
the other radio is switched into the power amplifier (PA) and the PA output is switched to the corresponding diplexer port.
This card also contains the RF fault detection circuitry, which detects anomalies by monitoring the antenna line of each
receiver-transmitter.
5-2.8 Receiver-Transmitters
Two receiver-transmitters are used in the bi-directional repeater. The type of receiver-transmitter used in the bi-
directional repeater is a transceiver (combination transmitter and receiver) capable of operating in the 30-88, 136-174,
or 403-470 MHz frequency bands. The receiver-transmitter used within the bi-directional repeater (RT-1695/TRC-199)
differs from the standard receiver-transmitter (RT-1696/U/(C)) only in that the repeater version does not have
encryption/decryption capability. The bi-directional repeater is COMSEC transparent and does not need to decrypt
encrypted traffic prior to relaying it back out over the transmit frequency.
Refer to TO 31R2-2PRC139-1 for additional information on the receiver-transmitter. TO 31R2-2PRC139-1 covers both
the RT-1695/TRC-199 and RT-1696/U(C) receiver-transmitters. Both receiver-transmitters are identical except the
RT-1696/U(C) is fitted with an INDICTOR COMSEC encryption/decryption integrated circuit and is designated a
Controlled Cryptographic Item (CCI). The RT-1696/U(C) receiver-transmitter, which is part of the AN/PRC-139(C) and
AN/GRC-238, shall not be used in the bi-directional repeater and cannot be physically inserted into the BDR sleeves. The
RT-1695/TRC-199 and RT-1696/U(C) receiver-transmitters have different notches on the chassis base (part of the battery
connector) that mate with matching notches in the different units in which they are installed. This prevents inadvertent
installation of the RT-1696/U(C) in the bi-directional repeater.