LigoWave 5 GHz Wireless Bridge CPE, 15 dBi Panel Antenna DLB-5-15N

What this radio is for

A wireless bridge carries a network across a gap by radio, so two places can share one network with no cable between them.

LigoWave calls this model a CPE, short for customer premises equipment: the radio at the far end of a link. It can also run as an access point, so it can take either end of a short link.

How it works

• Polling: with iPoll, the radio at the centre of the network gives each client a turn to send. That keeps clients from talking over one another when several share one base-station.
• MIMO 2x2: two radio chains work at once, one reason this radio can use faster 802.11n rates than 802.11a.
• Bridge or router: in bridge mode the link behaves much like a long network cable. Router modes are offered for iPv4 and IPv6, with or without NAT (network address translation).
• Adaptive modulation: the radio changes how densely it packs data to suit the signal it has. ATPC does a similar job for output power.

Where to use it

Typical jobs are an outbuilding, a gatehouse or a pole in a car park, where digging for cable would be costly.

The beam is only 35 deg wide, so the radios at each end need to be aimed at each other. Keep the path clear, because trees and buildings weaken a 5 GHz signal.

What the figures mean in practice

• 15 dBi: dBi measures how tightly an antenna focuses its signal. A higher figure reaches further along a narrower path.
• Up to 29 dBm (country dependent): this is the strongest output, and it falls at faster data rates. Local rules can set a lower limit, so check what applies where the radio is fitted.
• Radio rates and real speed: the 300 Mbps data rate is a radio figure, and the capacity is 170 Mbps. Plan around what the wired port and the path can really carry.
• Receive sensitivity: this is the weakest signal the radio can use, shown as a negative number. It runs from -97 dBm at slow rates to -75 dBm at the fastest, so a long link needs a clean path to keep its speed.
• Channel size: wider channels carry more data but use more of the band. This radio offers 5,10, 20 and 40 MHz.

Installing it

• Surge protection: the grounding lug and grounded PoE allow a professional installation, resistant to electrical surges, so connect the lug rather than leaving it empty.
• Aiming: the software includes site survey, link test and antenna alignment tools, so use them before tightening the bracket.
• Cable run: use outdoor-rated network cable for the run up to the radio, as indoor sheaths can crack in sunlight.
• Adapter position: keep the PoE adapter somewhere dry with a mains socket.

Planning your system

One unit is not a link, so budget for a radio at each end, or a base-station plus a client at each site. Confirm both ends share a mode before ordering.

The bracket and the PoE adapter are included. The job still needs network cable, a mains supply at the adapter and a switch or router to connect to.

If the link carries CCTV to a network video recorder, add up the bitrate of every camera first. Compare the total with the 170 Mbps capacity and the 10/100 wired port, and leave headroom.

Standards and ratings explained

• FCC, IC and CE: FCC is the US radio approval, IC the Canadian one and CE the European conformity marking.
• Firmware: check current firmware features in the web interface once installed.