Avidyne DC50 Datalink Coupler Installation Manual
Page 4
P/N 600-00082-000 Rev 04
2.3 Coupler Installation Requirements
For the antenna coupler to function correctly when connected to an
ORBCOMM datalink transceiver and a comm transceiver it
must
be
connected to a top mounted antenna capable of transmitting and
receiving both communications frequencies and datalink frequencies.
The VHF comm operates from 118 MHz to 136.975 MHz, and the
ORBCOMM transceiver transmits from 148 MHz to 150.05 MHz and
receives at 137 MHz to 138 MHz. This installation manual does not
contain approves data for antenna installations on specific aircraft types.
Low loss coaxial cable (RG400 or equivalent) must be used for all RF
connections. Coax cable is to be double shielded, have a loss of less
than 4.5 dB per 100 ft at 100 MHz and have a center-stranded
conductor.
The datalink function cannot operate when the VHF communications
radio is transmitting. Therefore, if there are two comms installed, the
coupler should be connected to the secondary comm. This configuration
will allow for best datalink operation.
Two different couplers are available:
-000 for 28 VDC Aircraft
-001 for 14 VDC Aircraft
Consult your pilots operating handbook to determine the aircraft system
voltage.
The Coupler
must
be powered from the same circuit breaker as the VHF
comm that is connected to it. This ensures that the coupler will never be
powered off while the comm transmits. If this were to happen it could
damage the Coupler.
The Coupler
must
be connected to the same PTT discrete as the comm
connected to it (usually the PTT switch is connected to an audio control
panel that in turn routes PTT to the selected VHF comm). Transmitting
into the coupler with the PTT discrete ungrounded could damage the
coupler.
CAUTION:
IF ANY OF THE REQUIREMENTS ABOVE ARE NOT ADHERED
TO, THE COUPLER MAY NOT FUNCTION CORRECTLY AND
MAY BE DAMAGED.
