General Interest / Specifications

» How far can the radios transmit?

Antenna selection affects the transmission range.

» How do the radios handle interference in the unlicensed spectrum?

AvaLAN products operate in the less saturated 900MHz and 5.8GHz bands. Unique to AvaLAN products is our frequency intelligence that merges the best of Frequency Hopping with Direct Sequence radio architecture. AvaLAN’s protocol continuously monitors the error rates of each packet to determine the quality of the link. If the error rate increases due to interference the AvaLAN product will autonomously change channels. With 12 channels at 900MHz and 58 channels at 5.8GHz the AvaLAN solution can intelligently adapt where frequency stagnant or random hopping systems fail.

» Why use 900 MHz or 5.8 GHz?

900MHz

Pros:
•    AvaLAN’s AW900 product line uses the 900MHz band and the equipment does not interfere with WiFi.
•    The AW900 product series does not require an FCC license.
•    900MHz provides great penetration power through walls and foliage.

Cons:
•    Only 12 channels are available at 900MHz and some areas, denser metropolitan areas, may not have the whole spectrum available reducing the number of available channels.

5.8GHz

Pros:
•    AvaLAN’s AW5800 product line uses the 5.8GHz band, the equipment does not interfere with WiFi.
•    The AW5800 product series does not require an FCC license.
•    With 58 channels available the AW5800 product series offers better functionality in dense metropolitan areas.
Cons:
•    5.8GHz does not penetrate and therefore must have a Line of Sight communication path.

» Why not use 2.4GHz or a WiFi system?

WiFi systems generally are less secure and may not work well due to radio saturation and interference. The range is also reduced due to the wider spectrum and higher frequency being used.

» What is the difference between the “TR” series and the “T” series radios?

The AW900xTR is identical to the AW900xT with the exception that it has an integrated web server that allows users to log into the radio using a standard internet browser. The same is true for the AW5800xTR vs. the AW5800xT.
When logged into the web interface it is possible to view diagnostic information, configure the radios and perform a spectral scan for interference.
The web interface works with most internet browsers by using an SVG plug-in for the Spectrum Analyzer (this plug-in is pre-installed in the Firefox browser).

» How do the radios handle retransmission of packets with errors?

AvaLAN products use a sub-block retransmission protocol rather than a full packet retransmission protocol. AvaLAN’s Smart Packet Fragmentation protocol breaks large Ethernet packets into smaller sub-blocks. If any sub-block has an error only that block is retransmitted instead of the whole packet.

Configuration / Troubleshooting

» How do I align the antennas?
All antennas need to be polarized the same for proper communication. The flat panel antennas have a sticker indicating polarization. Please refer to the charts below for proper alignment and polarization techniques. In the majority of cases simple eyeing techniques are sufficient to align the antennas. If unsure of alignment use the radios’ built-in link quality meter to indicate alignment.