Viavi/Aeroflex ATC-601 Mode S/A/C Transponder Ramp Test Set

Viavi / Aeroflex ATC-601 Features and Specifications *

The Aeroflex ATC-601 is a compact, portable, and highly functional avionics test set specifically designed for testing Mode A, C, and S transponders, including integrated Traffic Collision Avoidance System (TCAS) functionalities. Renowned for its reliability and ease of use, this test set has become a trusted tool in both civilian and military aviation maintenance environments. Developed by Aeroflex, the ATC-601 simplifies ground-based testing of airborne transponder systems, ensuring compliance with international standards and enhancing the accuracy and reliability of airborne communications and navigation systems. This serves as a bench and ramp test set for verifying the operation and calibration of aircraft transponders. Designed for use in hangars, line maintenance operations, and workshops, the unit simulates air traffic control interrogations and monitors the corresponding transponder replies. This ensures that each transponder is properly transmitting data on altitude, identification codes, and position information in response to air traffic control signals.The test set supports multiple ICAO transponder modes:

• Mode A: Provides aircraft identification information.
• Mode C: Transmits aircraft pressure altitude.
• Mode S: Offers advanced communication capabilities, including selective interrogation and data link functionality, used in modern TCAS systems.

Through these modes, the Aeroflex ATC-601 enables complete functionality testing, validation, and troubleshooting of essential avionics equipment, minimizing downtime and supporting compliance with regulatory standards such as FAA and EASA mandates.

This model is engineered to offer a balance of ruggedness, portability, and advanced testing capability. The unit provides complete verification of transponder responses across Mode A, C, and S. It can simulate ATC interrogations and evaluate transponder replies, including response accuracy, power output, frequency, and encoding of identification and altitude information. One of the most important upgrades from previous test sets is the built-in ability to simulate TCAS interrogations. The ATC601 evaluates TCAS transponders to ensure accurate response timing, format, and message content, a feature crucial for aircraft operating in controlled airspace where collision avoidance is a primary safety consideration. The test set features a simple control panel with intuitive menu navigation, making it easy for technicians to configure and initiate tests. Key test results are displayed clearly on the built-in screen, with automated test sequences that reduce human error and increase test repeatability. With its lightweight and compact design, it is particularly suitable for field operations. Maintenance personnel can easily transport it to different aircraft or locations, making it ideal for ramp and hangar use. Its battery-powered option further enhances mobility. This test equipment delivers consistent, high-precision test results. It is designed to operate within tight tolerances, which is essential for verifying transponder systems in high-stakes environments. Regular use of the ATC 601 as part of preventive maintenance routines can detect transponder issues before they result in communication or navigation errors. The ATC-601-2 is an enhanced version of the standard Aeroflex ATC-601, offering several critical upgrades while maintaining compatibility with the original model’s operating principles. It is engineered to accommodate evolving industry requirements, particularly in Mode S and TCAS test scenarios. While the original ATC-601 handles Mode S to a satisfactory level for most operators, the ATC-601-2 builds upon this with expanded capabilities for newer Mode S protocols and standards. It offers advanced bit-level analysis and supports extended squitter formats (ADS-B Out), which are becoming increasingly important due to regulatory changes worldwide. The ATC-601-2 includes an improved user interface with clearer displays and simplified navigation. This improvement boosts technician productivity and reduces the learning curve for less experienced operators. Unlike the standard ATC-601, the ATC-601-2 supports firmware and software updates, allowing users to keep the device compliant with future standards without needing to replace hardware. This feature extends the service life of the device and enhances return on investment.

As aviation technologies continue to evolve, tools like the Aeroflex ATC-601 remain vital in maintaining the accuracy and functionality of onboard systems. With increasing reliance on Mode S transponders for Automatic Dependent Surveillance–Broadcast (ADS-B) and other air traffic management systems, thorough ground-based verification is critical.The ATC-601 Transponder Test Set enables technicians to validate critical functionalities, including:

• Mode S data integrity.
• Altitude encoding accuracy.
• ADS-B compliance (particularly with ATC-601-2).
• Reply delay and power characteristics.
• ICAO address verification.

By accurately replicating ATC and TCAS interactions, this tester helps reduce flight-test dependencies and supports safer aircraft operations. It is designed with durability and maintainability in mind. Routine calibration ensures continued accuracy, and replacement parts are generally available through authorized service providers. Additionally, the widespread use of this model means support documentation, training, and accessories are readily accessible. For organizations that operate fleets with diverse aircraft types, having standardized, multi-mode test equipment like this simplifies the maintenance logistics. The ATC-601-2 variant’s upgradability further ensures longevity in dynamic regulatory environments. This device is a trusted and time-tested avionics test set that enables precise and efficient testing of Mode A, C, and S transponders, as well as TCAS systems. It is known for its portable design, intuitive operation, and robust performance in demanding environments. For operators requiring more advanced features and regulatory flexibility, the ATC-601-2 offers an enhanced solution with upgradable software, extended Mode S capabilities, and improved usability. Whether used in large commercial hangars, regional maintenance shops, or mobile MRO operations, the ATC-601 continues to play a critical role in ensuring avionics integrity and airspace safety. For avionics professionals seeking reliable, field-proven equipment with a reputation for performance, the Aeroflex ATC-601 remains a preferred choice.

The Aeroflex ATC-601 price and features make it a very attractive option comparing to similar transponder test sets available on the market. 

Features

• Supports interrogation and reply verification for Mode A, Mode C, and Mode S transponders.
• Provides simulation of TCAS aircraft to test transponder responses under realistic collision avoidance scenarios.
• Compact and lightweight build optimized for field use, ideal for both bench and ramp testing.
• Equipped with a user-friendly screen for real-time test data visualization and easy menu navigation.
• Offers the flexibility of battery-powered operation, enabling use in locations without immediate access to AC power.
• Includes predefined test routines to streamline common maintenance procedures and reduce human error.
• Supports both radiated (over-the-air) testing and direct coaxial connection to transponder output.

Benefits

• Reduces aircraft downtime with quick setup, automated testing, and fast result reporting.
• Helps maintain adherence to FAA, EASA, and ICAO requirements for transponder performance verification.
• Verifies critical transponder functions essential for ATC communication, traffic separation, and collision avoidance.
• Minimizes the need for expensive flight tests by offering comprehensive on-ground transponder diagnostics.
• Compatible with a wide range of transponder systems, from legacy Mode A/C to modern Mode S and TCAS-equipped aircraft.
• Simplified controls and readable displays reduce training requirements and improve productivity for avionics personnel.

Capabilities

1. Mode A Transponder Testing
• Simulates interrogation and measures aircraft identification response (Squawk code) accuracy and integrity.
2. Mode C Altitude Verification
• Evaluates encoded pressure altitude transmitted by the aircraft, essential for vertical separation.
3. Mode S Communication
• Assesses advanced Mode S functions including data link, selective interrogation, and error-free reply decoding.
4. TCAS Functionality Simulation
• Mimics nearby aircraft to verify transponder behavior in conflict alert scenarios, supporting airborne collision avoidance system checks.
5. Signal Strength and Frequency Analysis
• Measures and displays the transponder’s output power and frequency to ensure performance within specified tolerances.
6. Response Time and Format Validation
• Evaluates the timing, completeness, and accuracy of replies to ensure transponder responsiveness.
7. ICAO Address and Flight ID Testing
• Confirms that transmitted identification data matches programmed aircraft information.

Specifications

• Frequency Ranges:
• Interrogation: 1030 MHz
• Reply: 1090 MHz
• Supported Modes:
• Mode A, C, S (including TCAS and ADS-B compatibility in ATC-601-2)
• Power Measurement Range:
• 0.25 to 1,000 Watts Peak (Direct Connect)
• Up to 0.5 W Radiated Mode
• Display:
• High-contrast LCD with multi-line readout and menu-driven interface
• Connectivity:
• Antenna ports for radiated tests
• RF ports for direct coaxial testing
• Battery:
• Rechargeable battery pack for portable use
• AC power adapter for bench operation
• Dimensions:
• Approx. 11” x 8” x 4” (varies slightly by configuration)
• Weight:
• Under 10 lbs (varies slightly by model)
• Environmental Tolerance:
• Operating temperature range: typically 0°C to 50°C
• Ruggedized for field operations
• Variants:
• ATC-601: Standard model with full transponder and basic TCAS testing.
• ATC-601-2: Enhanced version with extended Mode S support, firmware upgradability, and advanced ADS-B testing.

BASIC INFORMATION

CHARACTERISTICS

* Viavi / Aeroflex ATC-601 technical specifications is provided for reference only. Avionteq cannot ensure accuracy of the technical specifications presented herein. The technical data may not relate entirely to all model and versions of the ATC-601 such as the models sold by Avionteq.

Viavi / Aeroflex ATC-601 Transponder / ADS-B Test Sets to Buy, Rent, Sell or Trade in

Avionteq offers both new and refurbished or used Viavi / Aeroflex ATC-601 Mode S/A/C transponder ramp test set for sale or rent at most competitive price. All refurbished equipment are thoroughly tested and come with our warranty and fresh calibration certificate (when required). You can also sell your excess / surplus Viavi / Aeroflex ATC-601 or receive trade-in credit towards purchase of other test equipment.