Thank you for purchasing the Ubiquiti Networks® airFiber®
AF‑LTU. This Quick Start Guide is designed to guide you
through installation and also includes warrantyterms.
Package Contents
airFiber AF‑LTU
Gigabit PoE (24V, 1A)
with Mounting Bracket
TERMS OF USE: Ubiquiti radio devices must be professionally installed. Shielded Ethernet
cable and earth grounding must be used as conditions of product warranty. TOUGHCable™ is
designed for outdoor installations. It is the professional installer’s responsibility to follow local
country regulations, including operation within legal frequency channels, output power, and
Dynamic Frequency Selection (DFS) requirements.
Metal Strap
5 GHz TDD
Point-to-MultiPoint Radio
Power CordQuick Start Guide
Model: AF-LTU
Antenna Compatibility
• The AF‑LTU is designed for use with the LTU‑Extend dish
antenna (not included).
• The AF‑LTU is also compatible with the following horn
antennas (not included):
• Prism®AP‑5‑30
• PrismAP‑5‑45
• PrismAP‑5‑60
• PrismAP‑5‑90
Hardware Overview
Reset
Button
Ethernet
Port
Ethernet Port This PoE port is used for handling all user traffic
and powering the device.
Reset Button To reset to factory defaults, press and hold the
Reset button for more than 10 seconds while the device is
already poweredon.
Release Button To detach the AF‑LTU from the antenna,
rotate the device counterclockwise while depressing the
Release Button. (To detach the AF‑LTU from a horn, rotate the
horn instead of the device.)
Release Button
Release Button
AF‑LTU Unmounted (Back View)
(not visible)
AF‑LTU Mounted on Antenna
LEDs
GPSSignalLINK
Ethernet
Ethernet
Activity
Link
Signal 1-4 These LEDs light the following colors when on:
• Signal 1 LED will light red when on.
1 2 3 4
• Signal 2 LED will light yellow when on.
• Signal 3 LED will light green when on.
• Signal 4 LED will light blue when on.
Bootup to airOS® When powering on, the GPS, Link, and
Signal 1‑4 LEDs light on. Once the CPU code takes over, the
GPS, Link, and Signal 1‑3 LEDs turn off. Signal 4 LEDremains on
to indicate the boot sequence is underway.
Initializing airFiber Software When the airFiber application
begins to boot under airOS, the Signal 4 LED goes from solid on
to a 2.5 Hz flash. This continues until the AF‑LTU is fully booted.
Signal Level Once fully booted, the Signal 1‑4 LEDs act as a
bar graph showing how close the AF‑LTU is to ideal aiming. This
is auto‑scaled based on the link range, the antenna gains, and
the configured TX power of the remote AF‑LTU. Each Signal LED
has three possible states: On, Flashing, and Off. All Signal LEDs
would be solidly on in an ideal link. If the link has a 1 dB loss, the
Signal4 LED will flash; a 2 dB loss and the Signal 4 LED will turn
off. The full bar graph LED states are shown below.
dB
0 ‑1 ‑2 ‑3 ‑4 ‑5 ‑6 ‑7 ‑8 ‑9 ‑10 ‑11 ‑12 ‑13
loss
1 F 0 0 0 0 0 0 0 0 0 0 0 0
1 1 1 F 0 0 0 0 0 0 0 0 0 0
1 1 1 1 1 F F 0 0 0 0 0 0 0
1 1 1 1 1 1 1 1 1 1 F F F 0
0 = Off, 1 = On, F = Flashing
Additional LEDs
LEDStateStatus
OffNo GPS Synchronization
GPS
Normal Flash* Non‑Operational (Weak Signal)
OnOperational (Strong Signal)
OffRF Off
Short Flash*Syncing
LINK
Normal Flash* Beaconing
Long Flash*Registering
OnOperational
OffNo Ethernet Activity
Ethernet
Activity
Random Flash Ethernet Activity
Off
Ethernet
Link
OnGigabit Ethernet Link
10/100 Base‑T Link or
No Ethernet Link
* Short Flash (1:3 on/off cycle)
Normal Flash (1:1 on/off cycle)
Long Flash (3:1 on/off cycle)
Installation Requirements
• Clear line of sight between airFiber radios
• Clear view of the sky for proper GPS operation
• Vertical mounting orientation
• Mounting point:
• At least 1 m below the highest point on the structure
• For tower installations, at least 3 m below the top of