Communication (Com) Transceivers - Cirrus SR22 Pilot Operating Handbook

Cirrus Design Section 7
SR22 Airplane Description
1 and 7.5-amp COM 1 circuit breakers on the Avionics Essential Bus.
The secondary GPS navigator is powered by 28 VDC through the 5-
amp GPS 2 and the 7.5-amp COM 2 circuit breaker on the Avionics
Non-Essential Bus.

Communication (COM) Transceivers

Avionics Configuration A, B, and PFD:
Two VHF communications (COM) transceivers are installed to provide
VHF communication. The transceivers and integrated controls are
mounted in the Garmin GNS 430 or GNS 420 units. The transceivers
receive all narrow- and wide-band VHF communication transmissions
transmitted within range of the selected frequency. The antennas pick
up the signals and route the communication signals to the
transceivers, which digitize the audible communication signal. The
digitized audio is then routed to the audio control unit for distribution to
the speakers or headphones.
COM 1 – The upper Garmin GNS 430 is designated COM 1. The
Garmin GNS 430 control panel provides COM 1 transceiver active and
standby frequency indication, frequency memory storage, and knob-
operated frequency selection. The COM 1 transceiver provides either
720-channel (25 kHz spacing) or 2280-channel (8.33 kHz spacing)
operation in a frequency range from 118.000 to 136.975 MHz. The
COM 1 antenna is located above the cabin on the airplane centerline.
28 VDC for COM 1 transceiver operation is controlled through the
Avionics Master Switch on the bolster switch panel and supplied
through the 7.5-amp COM 1 circuit breaker on the Essential Avionics
Bus.
COM 2 – The lower Garmin GNS 420 is designated COM 2. The
Garmin GNS control panel provides COM 2 transceiver active and
standby frequency indication, frequency memory storage, and knob-
operated frequency selection. The COM 2 transceiver provides either
720-channel (25 kHz spacing) or 2280-channel (8.33 kHz spacing)
operation in a frequency range from 118.000 to 136.975 MHz. The
COM 2 antenna is located on the underside of the cabin on the
airplane centerline. 28 VDC for COM 2 transceiver operation is
controlled through the Avionics Master Switch on the bolster switch
panel and supplied through the 7.5-amp COM 2 circuit breaker on the
Non-Essential Avionics Bus.
P/N 13772-001 7-101
Revision A10