41
Barrett 2040 Manpack Adaptor
A standard 2050 transceiver (with local front panel) when plugged into the 2040 Manpack adaptor,
converts the 2050 into a 2040 portable Manpack transceiver, complete with automatic antenna tuner.
When plugged into the adaptor, the output power is automatically reduced to low power operation.
The 2040 Manpack Adaptor has inbuilt battery charger and the battery is easily removed by a twist and pull
handle for easy replacement when required.
The 2040 Manpack adaptor contains five sections:-
Base PCB
Front panel PCB
Internal charger PCB
Automatic tuning antenna PCB
Removable Lithium Ion battery cartridge
The printed circuit board assemblies are housed within a strong water resistant chassis while the battery
pack is inserted into the bottom of the unit. Any 2050 transceiver can be deployed in the manpack adaptor
to provide full portable capability.
All signal, power and RF connections between the 2050 and 2040 are made through the base PCB,
eliminating the need for extra connection cables. The front panel of the 2040 contains 4 waterproof Military
specification connectors, one 50
Ω
BNC connector, and a threaded stud for attaching a whip or long-wire
antenna.
Base PCB
The base PCB provides all the required signal, power and RF connections between the 2050 transceiver
and the 2040 manpack.
P1 on the Transceiver Connection PCB plugs into the rear panel DB25 on the 2050 Transceiver and
passes all of the digital control and audio signals through to the other PCBs. P2 is the connection point for
the Automatic Tuning Antenna and provides the internal tuner with control signals, power supplies and the
RF connections from the 2050 transceiver. P3 provides the connections to the internal charger PCB. The
internal charger PCB transfers the battery voltage through to the 2050 Transceiver via P7 and provides
the signal lines from the front panel PCB through to the 2050 Transceiver.
Front Panel PCB
The front panel PCB provides all of the required signals to interface the 2040 Manpack with the external
accessories.
Connector P1 is a general input/output connector for use with encryption devices, computer interface and
data modems. The balanced input audio from P1 passes through a common mode choke T2 and uses
capacitors C15 and C16 for RF suppression. U2A forms a unity gain buffer amplifier to change the
balanced audio into single ended audio before it is passed to the summing amplifier U1B.
P2 is used to connect the speaker microphone. The microphone audio also passes through a common
mode choke T1 and RF suppression capacitor C14 before reaching amplifier U1A. U1A has a gain of 14dB
to increase the audio level of the microphone. MOSFET Q1 is used to disable the microphone audio when
the PTT button is released. Once the PTT button is released, a positive voltage on the gate results in the
drain pin being pulled towards ground. Any audio signal on the drain pin is also pulled to ground preventing
the signal from entering the amplifier. This is required to avoid receiver speaker audio from feeding back
through the transmit path of the transceiver. Resistors R14 and R15 provide DC bias to the electret
microphone element of the speaker/microphone.
