Viavi ALT-8000, ALT-8015 Test Note

Test Note

Radio Altimeter Test Procedure Using the
VIAVI ALT-8000/8015

The VIAVI ALT-8000/8015 RF-Based Portable Radio Altimeter Flight Line Test Set allows replication of in­flight conditions by simulating altitudes, including climb/descend profiles, to verify your installed system and
isolate a bad component.

This document provides the basic instructions to test an installed system. With little editing, it can be easily adapted to your aircraft platform for formal procedure development.

Contents

ALT-8000/8015 Test Setup ……………………………………………………………………………………. Page 1
Altitude Simulation Test via Direct-Connect ……………………………………………………….………… Page 5
Altitude Simulation Test via Coupler …………...…………………………………………………….………. Page 7
Profile Test – Direct or Coupler…...…………………………………………………………………………… Page 9

Radio Altimeter Sensitivity Test – Direct or Coupler …….……….………………………………….……. Page 13

ALT-8000/8015 Test Setup

Radio altimeter: Ensure the aircraft or bench test fixture is energized, however the radio altimeter should be
in the OFF condition.

ALT-8000/8015:

1. Press the Power On button on the front of the ALT-8000 to power on the test set. See Fig. 1-1.

Figure 1-1 Power On Button

VIAVI ALT-8000/8015

2. On the launch bar, press the Test Setup function key. See Figure 1-2.

Figure 1-2 Launch Bar

3. Locate the two 20 ft cables (P/N 88511 and 89527), the two 4 ft cables (P/N 91253 and 91255) or
the 100 ft cable set (P/N 88500), whichever will be used.

NOTE: The 20 ft cables will be referenced in this procedure.

4. Connect the cable with the yellow ends (P/N 88511) to the UUT:RX (Yellow) connector on the top
panel of the ALT-8000/8015. See Figure 1-3.

5. Connect the cable with the red ends (P/N 89527) to the UUT:TX (Red) connector of the ALT­8000/8015. See Figure 1-3.

Page 2

Figure 1-3 ALT-8000/8015 Top Panel

VIAVI ALT-8000/8015

Figure 1-4 Test Setup Screen

Figure 1-5 Delay Calibration Screen

6. Connect the other ends of the 20 ft cables together, using one of the supplied TNC to TNC Adapters
(P/N 38353).

NOTE: For the Delay Calibration, the 20 dB attenuators should NOT be installed on the ALT­8000/8015.

7. On the Test Setup screen, press the Delay Calibration button. See Figure 1-4.

8. On the Delay Calibration screen, press the Start button to start the delay calibration. See Figure 1-5.

NOTE: The calibration process is automatic. When delay calibration is complete, the Test Setup screen
is displayed.

Page 3

VIAVI ALT-8000/8015

Figure 1-6 Loss Setup Screen

9. Remove the TNC to TNC Adapter from between the TX and RX cables.

10. Set UUT Settings – UUT Detect Mode to Auto. See Figure 1-4.

11. Set RF Settings – Level Mode to Auto. See Figure 1-4.

12. On the Test Setup screen, press the Loss button to go to the Loss setup page. See Figures 1-4
and 1-6.

13. Locate the cable loss value listed on the cable connected to the UUT:TX port (Red) and enter this
value as Cable Loss – UUT:TX Cable Loss (Red). See Figure 1-6.

14. Locate the cable loss value listed on the cable connected to the UUT:RX port (Yellow) and enter this
value as Cable Loss – UUT:RX Cable Loss (Yellow) See Figure 1-6.

15. For coupler testing, enter 20 dB as Ext. Attenuation – UUT:RX Attenuation (Yellow) and for direct
connect testing, enter 40 dB as Ext. Attenuation – UUT:RX Attenuation (Yellow). See Figure 1-6.

NOTE: 20 dB attenuators are only required for pulse type radio altimeters. They are not used for
FMCW and FMCW-CDF type radio altimeters.

16. Locate the coupler with the red UUT:TX label and then locate the Loss Value label on the coupler.
Enter the Coupler Loss Value as Coupler Loss – UUT:TX Coupler Loss (Red). See Figure 1-6.

17. Locate the coupler with the yellow UUT:RX label and then locate the Loss Value label on the
coupler. Enter the Coupler Loss Value as Coupler Loss – UUT:RX Coupler Loss (Yellow). See
Figure 1-6.

Page 4

VIAVI ALT-8000/8015

Figure 2-1 Test Setup - Direct

Altitude Simulation Test via Direct-Connect

1. Perform the ALT-8000/8015 Test Setup instructions beginning on page 1.

2. Ensure that two of the 20 dB TNC attenuators are connected to the UUT:RX Port (Yellow) of the
ALT-8000/8015. Connect one 20 dB attenuator directly to the ALT-8000/8015 and then connect the
second 20 dB attenuator directly to the first one. Then connect the coax to these attenuators.

NOTE: 20 dB attenuators are only required for pulse type radio altimeters. They are not used for
FMCW and FMCW-CDF type radio altimeters.

3. Connect the red coaxial cable to the TX port of the radio altimeter being tested. Connect the yellow
coax to the RX port of the radio altimeter being tested.

4. Apply power to the radio altimeter being tested.

5. Set RF Settings – Connection Type to Direct. See Figure 2-1.

6. Touch the gray vertical bar on the left side of the display to display the launch bar.

7. On the launch bar, press the Simulation function key. See Figure 1-2 and 2-2.

Page 5