IFR NAV-401L Avionics Ramp Test Set

The Cobham / Aeroflex / IFR NAV-401L is a self-contained ramp and bench test set designed for the comprehensive functional testing and calibration of aviation navigation and communication equipment. It is engineered to meet the requirements for Category I and Category II ILS systems, as well as COMM, NAV, and Marker (MKR) systems. The NAV-401L integrates a modulated signal generator with a variable output attenuator, offering both crystal and variable frequency modes across multiple bands. Its capabilities extend to testing VOR, Localizer (LOC), Glide Slope (G/S), Marker beacons, and communication systems. The unit includes built-in monitoring and measurement features such as a percentage of modulation monitor, a VOR bearing monitor, and an RF power meter for COMM transmitters. Additionally, it features a built-in counter for frequency display and a power source that can operate from an AC supply or an internal rechargeable battery.

### Technical Specifications

* **Product Type:** Ramp and Bench Test Set for Avionics
* **Manufacturers:** Cobham, Aeroflex, IFR, Marconi, Viavi Solutions
* **Model:** NAV-401L
* **Intended Use:** Testing and calibration of NAV, COMM, ILS, GS, VOR, and MKR systems.
* **System Compatibility:** Category I and Category II ILS systems.

### Signal Generation

* **Signal Generator Capabilities:** Generates signals for MKR, VOR, LOC, G/S, and COMM systems.
* **Frequency Modes:**
* XTAL (Crystal) mode: Utilizes pre-defined crystal frequencies.
* VAR (Variable) mode: Allows for continuously tunable frequencies within each band.
* **Frequency Bands (Crystal Control):**
* 75 MHz
* 108.0 MHz
* 108.1 MHz
* 126.9 MHz
* 334.7 MHz
* *Note: Any frequency may be chosen in each band at the time of test set order.*
* **Frequency Tolerance (Crystal Control):** ±0.005%
* **Frequency Phase-Locking:**
* All bands: 25 kHz intervals (except G/S)
* G/S: 50 kHz intervals
* **Variable Mode Frequency Tolerance:** ±0.002%
* **Output Attenuator:** Variable output attenuator.
* **Maximum Output:** -7 dBm (0.1 V) on any band.
* **Output Range:** -7 dBm to -110 dBm.
* **Internal Localizer Transmitter:** Approximately -18 dBm output at the generator output jack for simultaneous LOC and G/S signal radiation in G/S XTL mode with LOC switch active.

### Modulation and Tones

* **Modulation Types:**
* MKR: 95% modulation ±5%
* VOR: 30% modulation ±2%
* COMM: 30% modulation ±2%
* LOC & G/S: 30% modulation ±2%
* **Modulating Tones (Digitally Derived):**
* 1020 Hz (Indent tone)
* 400 Hz
* 1300 Hz
* 3000 Hz
* *Tone Accuracy:* ±1%
* **NAV Tone Phase Accuracy (LOC and G/S):**
* Phase-locked with an accuracy of 0.1 degrees relative to the 30 Hz Reference signal.
* Relative phase between 90 Hz and 150 Hz tones can be varied in 5-degree steps.
* **Modulation Percentage Monitor:** Accurately indicates modulation levels on any band (0-30% or 0-100%).

### VOR Testing Capabilities

* **VOR Bearing Selection:** Selectable in 0.1-degree steps.
* **VOR Bearing Accuracy:** ±0.1 degree.
* **Built-in VOR Bearing Monitor:** Provides a 90-degree bearing monitor of VOR output.
* **VOR Course Derivation:** 3600 digitally derived courses.

### LOC and G/S Testing Capabilities

* **DDM (Depth of Modulation) – LOC:**
* Available DDM values: 0.093, 0.155, 0.200 DDM (with tone delete for flag tests).
* Accuracy: ±0.0013 DDM (±1.3 µA).
* Variable Control: ±0.4 DDM.
* **DDM (Depth of Modulation) – G/S:**
* Available DDM values: 0.091, 0.175, 0.400 DDM (with tone delete for flag tests).
* Accuracy: ±0.0024 DDM (±2.0 µA).
* Variable Control: ±0.8 DDM.
* **Modulation (LOC):** 20% (±2%) for each tone (90 Hz, 150 Hz).
* **Modulation (G/S):** 40% (±2%) for each tone (90 Hz, 150 Hz).
* **LOC/G/S Centering Calibration:** Calibratable from the front panel.

### COMM Testing Capabilities

* **RF Power Meter:** Measures COMM transmitter power.
* Range: 0-10 W or 0-100 W.
* Selection: Peak or average power switch.
* **COMM Transmitter Demodulation Output:** Allows viewing or listening to COMM modulation.

### Built-in Counter

* **Functions:** Displays generator frequency, COMM transmitter frequency, or 0 dBm external frequencies.
* **External Frequency Range:** 1 MHz to at least 300 MHz.
* **Counter Time Base Accuracy:** ±0.002% (derived from a 10 MHz clock oscillator).

### Electrical and Power

* **AC Supply Operation:**
* Input Voltage: 115 V / 230 V
* Frequency: 50 Hz to 500 Hz
* **Internal Battery:**
* Type: Rechargeable NICAD battery system (e.g., 2.0 AH).
* Ramp Operation Time: Approximately 2 hours (with counter off).
* Automatic Power Off: Unit automatically powers off after 10 minutes of inactivity to conserve battery life.
* Counter Operation on Battery: Operates only when the counter activate button is pressed.
* Battery Charging: Continuous charging is supported while the unit is plugged in, regardless of whether it is powered on or off.

### Physical Characteristics

* **Dimensions (H x W x D):** 5.1 inches (13.0 cm) x 11.4 inches (29.0 cm) x 16.1 inches (41.0 cm)
* **Weight:** Approximately 18 lbs (8.1 kg) (with 2.0 AH NICAD battery supply and AC charger).
* **Case:** Portable case.

### Interfaces

* RF Output Connector
* Modulation Input / External Frequency Counter Input Connector
* COMM Receiver Antenna Connectors (also used for COMM Transmitter Connector)

### Environmental

* **Operating Temperature:** 0°C to 50°C

Why Choose Aumictech for Cobham / Aeroflex / IFR NAV-401L?
At Aumictech, we specialize in supplying high-end avionics test equipment. Whether you need a reliable test set for comprehensive VOR, ILS, and COMM system calibration, a portable solution for ramp testing, or robust equipment for laboratory diagnostics, our team ensures the Cobham / Aeroflex / IFR NAV-401L delivers maximum performance for your aviation maintenance and certification applications.