CI 105

The Comant CI 105 is a broadband L-band blade antenna designed for aircraft transponder, ADS-B Out and DME applications across the 960–1220 MHz frequency range. The standard CI 105 uses a two-stud mounting configuration with a BNC female connector and is suitable for top- or bottom-mounted installations on light fixed-wing single-engine, multi-engine and helicopter aircraft where the CI 105 is specified or otherwise approved for use.

Designed for demanding airborne RF service, the CI 105 provides 50 Ω impedance, vertical polarization and a radiation pattern equivalent to a quarter-wave stub. Comant specifies a maximum VSWR of 1.5:1 across 960–1220 MHz, improving to 1.3:1 maximum from 1025–1150 MHz, with an RF power rating of 2.5 kW peak.

The compact blade measures approximately 3.23 inches high and weighs just 0.24 lb. Comant’s current datasheet specifies a glossy white finish, while the installation drawing documents the standard two-stud footprint, BNC female connector and associated aircraft mounting/connector-clearance dimensions.

For operational capability, the manufacturer installation drawing specifies 400 knots TAS at 25,000 ft, while the current datasheet lists environmental operation from -55°C to +85°C and altitude capability to 70,000 ft.

The CI 105 carries FAA TSO-C66b and TSO-C74c authorization and is environmentally qualified to RTCA DO-160C. As with any TSO-authorized article, the antenna’s authorization does not by itself establish installation eligibility for a particular aircraft; the applicable aircraft, avionics and installation data still need to be reviewed.

Key Features

• Applications: Transponder / ADS-B Out / DME
• Frequency range: 960–1220 MHz
• Impedance: 50 Ω
• VSWR: 1.5:1 maximum, 960–1220 MHz
• VSWR: 1.3:1 maximum, 1025–1150 MHz
• Polarization: Vertical
• Radiation pattern: Equivalent to a 1/4-wave stub
• RF power: 2.5 kW peak
• Connector: BNC female
• Mounting: Two-stud blade configuration
• Height: 3.23 in
• Weight: 0.24 lb
• Maximum published airspeed: 400 knots TAS at 25,000 ft
• Operating temperature: -55°C to +85°C
• Maximum published altitude: 70,000 ft
• Finish: Glossy white
• FAA TSO: C66b, C74c
• Environmental qualification: RTCA DO-160C
• Gasket reference: B10505

Designed for Aircraft L-Band Systems

The CI 105 covers the broad 960–1220 MHz L-band range used by the applications Comant specifies for this model, allowing one compact antenna design to support transponder, ADS-B Out and DME installations where approved for the aircraft and equipment combination.

Its combination of a compact blade profile, two-stud mounting arrangement, standard BNC female connection and documented high-altitude/high-speed capability has made the CI 105 a long-established antenna configuration for general aviation and other light-aircraft installations.

For replacement work, verify the complete antenna part number, mounting footprint, connector arrangement and current installation documentation before ordering. Comant publishes several CI 105-family variants with different mounting and connector configurations, so a CI 105-3, CI 105-6, CI 105-9, CI 105-16 or other derivative should not be assumed interchangeable with the standard CI 105 solely because the electrical frequency range is similar.

Standard CI 105 Configuration

The standard CI 105 shown here is the two-internal-hole-stud-mount version with a BNC female port. That distinction matters because other members of the CI 105 family use different stud lengths, flange patterns, connectors or mounting arrangements. Always match the exact suffix and installation drawing to the aircraft being serviced.