ATA Chapter 23 — N720AK Systems Reference
N720AK’s communications stack includes the Garmin GMA 245 audio panel, Dynon Com Panel , and intercom system. The audio panel provides Bluetooth connectivity for phone calls and music.
Component Part Number Supplier Notes
Audio panel GMA 245 Garmin Bluetooth, IntelliVox Com radio GTN 650 ComGarmin Integrated in GTN 650 Dynon Com panel SV-COM-425 Dynon Com frequency control Nav antenna Bob Archer Single nav antenna for GTN 650 Com antenna 1 CI-121 Comant Top of fuselage Com antenna 2 CI-122 Comant Bottom of right wing Intercom GMA 245 internal Garmin 4-place
Spec CI-121 (top of fuselage) CI-122 (bottom of right wing)
Frequency 118–137 MHz 118–137 MHz VSWR 2.5:1 max 3.0:1 Polarization Vertical Vertical Pattern Omnidirectional Omnidirectional Impedance 50 Ω 50 Ω Power 50 W 50 W Weight 0.5 lb max 0.5 lb max Height 18.50 in max 8.75 in max Material Cast housing / fiberglass whip Cast housing / stainless whip Connector BNC female BNC FAA TSO C37d, C38d C37d, C38d Gasket B12607-3 cork neoprene C12607-3 cork neoprene
The CI-121 is a straight vertical whip (standard Cessna-style). The CI-122 is a bent configuration designed for underside mounting.
All antenna coax is RG-400. See wing root connectors for the right wing COM antenna coax routing through the wing root CPC.
Bob Archer — single nav antenna for GTN 650
See also Navigation & Instruments .
Spec 104-12 Transponder 104-17 ADS-B
Frequency 1030–1090 MHz 978 MHz VSWR 1.2:1 @ 1090 MHz, <2:1 @ 1030 MHz — Length 3-1/8″ (79.4 mm) 3-3/8″ (85.7 mm) Weight 0.053 lb 0.053 lb Connector BNC female BNC male Mounting O-ring sealed bulkhead feed-through O-ring sealed bulkhead feed-through Source SteinAir SteinAir
Both are non-TSO monopole antennas fed by 50 Ω RG-400 coax, with omnidirectional vertically-polarized radiation patterns.
Parameter Value
Model SV-GPS-250/A Type Combined GPS receiver + antenna module WAAS Yes Update rate 5 Hz Weight 6.7 oz Connections 4 leads to SkyView DB37 via Serial Port 5 Power 8 VDC from SkyView DB37 pin 29 (GPS POWER OUT) Ground SkyView DB37 pin 24 (GPS GND) Data TX GPS gray/violet wire → DB37 pin 11 (Serial 5 RX) Data RX GPS gray/orange wire → DB37 pin 12 (Serial 5 TX) Baud rate 38,400 (SV-GPS-250); Serial Port 5 configured as POS 1 Mounting Overhead console Used by Dynon SkyView HDX
Parameter Value
Model GA 35 Part number 013-00235-00 Type Passive GPS/WAAS antenna with built-in LNA Frequency 1575.42 MHz ±10 MHz (L1 GPS/WAAS) Gain 27+ dB at +25°C nominal Impedance 50 Ω Connector Female TNC Supply current 60 mA max Weight 0.47 lbs Dimensions 4.68 × 3.00 × 0.81 in Mounting 4x #8-32 oval head SS screws, 12–15 in-lbs torque Certification TSO-C144.9 Mounting Overhead console Used by Garmin GTN 650
Parameter Value
Model ACR Artex 110-773 (Rev C)Type Dual-band whip antenna Frequencies 121.5 MHz and 406.0 MHz Connector BNC female Speed rating Fixed-wing up to 200 knots Included with Artex ELT 345 kit
Function Antenna Location
COM 1 Comant CI-121 Top of fuselage COM 2 Comant CI-122 Bottom of right wing NAV Bob Archer Transponder SteinAir 104-12 ADS-B SteinAir 104-17 Dynon GPS Dynon SV-GPS-250/A Overhead console GTN 650 GPS Garmin GA 35 Overhead console ELT ACR Artex 110-773