Trig TT23 Mode S and 1090ES ADS-B Transponder without GPS Overview:

Trig TT23 Compact Transponder (No Built-In GPS)

The TT23 is a next-generation compact transponder known for its efficient design, reliability, and full ADS-B compatibility when paired with an approved external GPS source. This lightweight, space-saving Mode S transponder is ideal for certified, experimental, and light-sport aircraft seeking a high-performance, low-power solution that fits even the tightest panels.

With minimal size and weight, the TT23 is designed to maximize panel space. It fits into a 57mm round hole or compact mount and includes all necessary installation hardware. The TT23 provides 250 watts of nominal output power, making it a Class 1 Mode S transponder suitable for both VFR and IFR operations, and fully visible to commercial, military, and general aviation traffic.

All Trig compact transponders are made up of two main parts: a compact control head with a built-in altitude encoder and a separate hardware box that can be installed anywhere on the airframe. The control head is just 54mm (2 3/25”) deep and fits in a panel with a 57mm (2 1/4”) round hole or a smaller compact mount – it comes with all the necessary fittings for either installation option. These compact transponders are highly efficient and commonly used in general aviation aircraft, gliders, and balloons, especially when paired with an auxiliary battery.

Trig’s compact transponders are easy to use, offering a clear, bright display that remains readable in any lighting condition and can be manually dimmed. The control head is also splash-proof, making it an excellent choice for open cockpit and seaplane operations.

Trig TT23 Key Features:

• Compact form factor – fits compact or standard 57mm instrument hole
• Requires an external GPS source for ADS-B Out (such as the TN70)
• Integrated altitude encoder
• Certified for IFR / VFR flight
• Bright, backlit LCD display with manual dimming
• Simple, one-handed operation – easy to use with gloves
• Low power consumption with fanless cooling design
• Splash-proof control head – great for open cockpit use
• Compatible with TC20 Control Head (optional)
• Optional GPS-integrated version available: TT23G

Certifications and Compliance:

• ETSO C88a, C112e, 2C112b, C166b
• TSO C88b, C112c – approved for IFR and VFR flight
• Meets ED-73E, ED-14G, DO-160G, DO-260B, DO-178C/B, DO-254 Level C

Specifications:

• Supply voltage: 11–33 V DC
• Current draw (typical at 14V): idle 0.15A, active 0.28A
• Nominal transmitter power: 250W at connector
• Operating temp: -40°C to +70°C (transponder), -20°C to +55°C (controller)
• Cooling: fanless – no additional cooling required
• Weight: 0.66 lbs (300 g)
• Controller dimensions: 1.8" H x 2.4" W x 2.1" L
• Transponder dimensions: 1.5" H x 2.6" W x 5.9" L

What’s Included:

• TT23 transponder and controller
• Mounting tray
• Installation kit (compact and round mounts)
• Installation and operating manuals (English, German, French)
• EASA Form One
• Two-year warranty from date of installation

Compatible Products:

• TN70 GPS – certified WAAS GPS source for ADS-B Out in certified aircraft
• TC20 Control Head – supports compact or 57mm round mount
• GPS-integrated alternative available: TT23G

Frequently Asked Questions:

What is the difference between the TT23 and the TT23G?
The TT23 requires an external GPS source for ADS-B Out, such as the TN70. The TT23G includes a built-in GPS certified to ETSO-C199 for a fully integrated ADS-B Out solution.

Is the controller display visible in all lighting conditions?
Yes, the backlit LCD display is easy to read in direct sunlight as well as low-light conditions. Manual dimming allows you to adjust brightness as needed.

Is the controller easy to use?
Yes. The 'CODE' dial and 'ENT' button allow simple, one-handed operation—even when wearing gloves.

How does the compact or round mount installation work?
The included TC20 control head can be installed in either a compact cutout or a standard 57mm round hole. The installation kit provides both options and includes a cutting template.

Can I use the TT23 in an open cockpit aircraft?
Yes. The TC20 control head is splash-proof, making it suitable for open cockpit and seaplane operations.

Does the TT23 have an STC?
Trig is working with Matrea Aerospace Design on an STC covering over 500 aircraft types. This STC will apply to the TT23 when paired with a compatible WAAS GPS source. It will not apply to the TT23G.

How do I use the TT23 for ADS-B Out compliance?
The TT23, when paired with a suitable external GPS source such as the TN70 or an approved WAAS IFR navigator, is ADS-B Out compliant in experimental, LSA, and (pending final STC) type-certificated aircraft in the U.S.