User's Manual

TY91/TY92 VHF Radio Installation Manual 11 April 2012
00839-00 Issue AA
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22 Trig Avionics Limited
priority over the music input.
5.6.10 Microphone Input
Microphone connections should be made using shielded twisted pair cables.
The two microphone inputs are identical, and have a nominal sensitivity of 100
mV into a 600 ohm load. Phantom power is supplied on the microphone inputs
to support a preamplifier.
5.6.11 Power Input
The TY91 power supply can be 11-33 volts DC; no voltage adjustment is
required. The TY92 power supply must be 22-33 volts DC. Use a 5 Amp
circuit breaker for power supply protection to the TY91 and TY92.
The peak current consumption on transmit exceeds the current capability of a
single pin on the connector. Both power inputs must be wired, and at least two
ground returns must be wired. This is particularly important when the VHF
radio is mounted on a non-conducting surface, such as a composite structure.
Use 20 AWG wire for the power connection wires.
5.6.12 Ground Returns
There are only 5 ground pins on the 25 way connector, at pins 1, 9, 10, 19 and
22. A full wiring loom with speaker, two headsets, two microphones, the TC90
connection, power and ground requires 9 ground connections. It is therefore
necessary to double up connections to ground pins. This is usually achieved by
bringing a short ground wire from a pin that then acts as a bus point inside the
D shell.
5.7 TC90 Controller Electrical Connections
The TC90 controller has a single 15 way D type male connector to link to the
VHF radio, and optionally to connect to a GPS for loading frequencies of
nearby airfields.