echoUAT Troubleshooting Guide

This guide covers common echoUAT problems involving power, Wi-Fi, transponder monitoring, altitude, GPS position, ADS-B traffic and weather, and FAA Public ADS-B Performance Reports (PAPRs).

The echoUAT is a discontinued product. uAvionix no longer sells replacement units or provides repair or rework service. Troubleshooting should confirm the installation, configuration, and connected equipment before concluding that the echoUAT has failed.

Begin With the Monitor Screen

The echoUAT Monitor screen provides the quickest way to determine which input is missing.

1. Power the aircraft and echoUAT.
2. Connect your phone or tablet to the echoUAT Wi-Fi network.
3. Open the echoUAT application.
4. Select Monitor.
5. Verify the following information:
   • Correct squawk code
   • Pressure altitude
   • GPS position
   • Aircraft ICAO address
   • ADS-B transmit and receive activity

Troubleshoot the missing or incorrect value before conducting another flight test.

echoUAT Does Not Power On

Check the following:

• Verify aircraft power at the echoUAT connector.
• Check the circuit breaker or fuse.
• Inspect the power and ground connections.
• Confirm the connector is fully seated.
• Look for loose terminals, damaged wiring, corrosion, or poor grounds.
• Verify that the aircraft voltage is within the limits specified in the installation manual.

A poor ground can cause intermittent operation, Wi-Fi disconnections, GPS errors, or failed ADS-B performance reports.

Indicator Lights

A red light flashing approximately once per second normally indicates ADS-B transmissions. A randomly flashing green light indicates received ADS-B information. These indications alone do not represent a failure.

echoUAT Wi-Fi Network Is Missing

If the echoUAT is powered but its Wi-Fi network does not appear:

1. Confirm power and ground at the unit.
2. Power-cycle the echoUAT.
3. Turn the phone or tablet’s Wi-Fi off and back on.
4. Search again for the echoUAT network.
5. Try a different phone or tablet.

If the Wi-Fi network remains unavailable, inspect the unit through the openings near the power connector. A steady blue internal light may indicate that the Wi-Fi hardware has failed. Contact uAvionix Support to confirm the diagnosis.

The Phone or Tablet Keeps Disconnecting

Mobile devices may leave the echoUAT network because it does not provide internet access.

• Disable automatic network switching.
• Turn off cellular hotspot features on nearby devices.
• Set the tablet to ask before joining other networks.
• Forget competing Wi-Fi networks temporarily.
• Confirm the device remains connected to the echoUAT while the aviation application is open.
• Disable any setting that automatically switches from Wi-Fi to cellular data.

After reconnecting, reopen the aviation application and confirm that the echoUAT appears as a connected device.

Squawk Code Is Missing or Incorrect

The echoUAT must receive the same Mode 3/A squawk code being transmitted by the aircraft’s transponder. An incorrect or missing code can cause PAPR failures, ATC discrepancies, or a duplicate “ghost” aircraft.

Before Adjusting the Threshold

• Confirm the aircraft has a compatible Mode C transponder.
• Place the transponder in ALT mode.
• Confirm the transponder is being interrogated by radar or an appropriate test set.
• Look for regular activity from the transponder’s reply indicator.
• Open the echoUAT Monitor screen and compare its squawk code with the transponder.

Adjust the Transponder Monitor Threshold

1. Open the echoUAT application.
2. Select Configure.
3. Tap the ECHO box three times to reveal the advanced settings.
4. Open Advanced.
5. Locate Transponder Monitor Threshold.
6. Adjust the threshold in small increments.
7. Save or update the configuration after each change.
8. Wait 30–60 seconds and check the Monitor screen.
9. Continue until the displayed code is stable and matches the transponder.

Do not select a threshold based only on a typical value. Aircraft wiring, antenna placement, transponder output, and installation geometry can affect the required setting.

ATC Sees Two Squawk Codes

This normally means the echoUAT is not synchronized with the aircraft transponder.

Verify that:

• The transponder is in ALT mode.
• The echoUAT Monitor screen shows the assigned squawk code.
• The transponder monitor threshold is properly adjusted.
• The code remains stable during repeated transponder replies.

If the echoUAT cannot detect the transponder, it may transmit an incorrect code, including zeros, while the transponder transmits the assigned code.

A Ghost Image Appears Near the Aircraft

A nearby duplicate or “ownship ghost” is commonly caused by a mismatch between the echoUAT transmission and the aircraft’s transponder transmission.

Check:

• ICAO address
• Tail number
• Squawk code
• Pressure altitude
• Transponder monitor threshold
• Configuration in the connected aviation application

The ICAO address must be entered correctly and must match the aircraft registration.

echoUAT No Longer Detects the Transponder

First confirm that the transponder itself is operating correctly and replying to interrogations. Then inspect the echoUAT Monitor screen and readjust the transponder threshold if necessary.

Some Mode S transponders may no longer work reliably with the echoUAT’s wireless transponder-monitoring function due to changes in radar interrogation behavior. uAvionix specifically notes this issue with the Garmin GTX 330. Those installations may require a hardwired data connection; however, the echoUAT MUX cable has been discontinued and is no longer available from uAvionix.

Pressure Altitude Is Missing or Incorrect

The echoUAT must receive pressure altitude from a compatible source.

Check whether the installation uses:

• An echoALT blind encoder, or
• A supported hardwired encoder or transponder data source.

Then verify:

• The echoALT or encoder has power and ground.
• Connectors and wiring are secure.
• The echoUAT Monitor screen displays pressure altitude.
• The displayed altitude is reasonable when compared with the aircraft encoder or transponder test equipment.

The echoALT is required when the echoUAT is not receiving altitude from another approved hardwired source. Transponder monitoring alone may not provide altitude when the aircraft is outside radar coverage.

GPS Position Is Missing or Invalid

Check:

• Power and ground to the approved GPS source
• GPS antenna placement and condition
• Coaxial cable and connectors, if applicable
• Serial-data wiring between the GPS and echoUAT
• Correct serial-data configuration
• Whether the GPS has an unobstructed view of the sky

If using a skyFYX or skyFYX-ext, confirm its output is connected correctly to the echoUAT. The skyFYX GPS output should not be split and shared with an AV-30.

Persistent NIC or NACp failures may indicate degraded GPS reception, electrical noise, poor grounding, antenna problems, or an incorrect GPS configuration.

No Traffic or Weather Is Displayed

Verify the problem in this order:

1. Confirm the tablet is connected to the echoUAT Wi-Fi network.
2. Confirm the aviation application recognizes the echoUAT.
3. Verify that the application is configured to display traffic and weather.
4. Check the echoUAT receive activity.
5. Inspect the ADS-B antenna, coaxial cable, and connectors.
6. Test while airborne and within ADS-B ground-station coverage.

Weather and some traffic services depend on reception from the FAA ground network. Limited results on the ground or in an area with poor tower coverage do not necessarily indicate an equipment failure.

Traffic Appears, but ADS-B Out Does Not Work

ADS-B In and ADS-B Out are separate functions. Receiving traffic does not confirm that the echoUAT is transmitting compliant ADS-B Out data.

Check:

• GPS position
• Pressure altitude
• Squawk code
• ICAO address
• Transmit antenna and coax
• Aircraft identification
• Transponder synchronization

Request an FAA PAPR after correcting the installation and conducting an appropriate validation flight.

Do not change unrelated configuration values simply to clear a PAPR failure. Identify the failed parameter and troubleshoot the source supplying that information.

When to Contact Support

Before contacting uAvionix Support, collect:

• echoUAT serial number
• Aircraft registration
• Transponder make and model
• GPS source
• Altitude source
• Current echoUAT configuration screenshots
• Monitor-screen screenshots
• FAA PAPR
• Description of recent maintenance or avionics work
• Details of when the problem began

Because the echoUAT is discontinued, uAvionix can help confirm the diagnosis but cannot repair or replace a failed unit. If ADS-B Out has failed but ADS-B In still operates, the echoUAT may continue to provide traffic and weather while another compatible product supplies ADS-B Out.

Refer to the current echoUAT FAQs and the echoUAT User and Installation Guide for approved installation and configuration information.