A point-to-point wireless link uses a pair of directional radios to carry network traffic between two locations, such as two buildings on a campus, a yard office and a main plant, or a remote site and the nearest network connection. Done well, it behaves like a long Ethernet cable. Its performance depends on clear line of sight, the right frequency band, solid mounting and a design with enough margin for weather.
When a wireless link makes sense
Point-to-point links are usually chosen when running cable is impractical or slow:
- Connecting buildings across a road, river, rail line or property you do not own
- Linking yards, gatehouses, pump stations or remote sites to a main network
- Providing a backup path alongside fibre or a carrier circuit
- Getting a temporary site, such as a construction office, connected quickly
- Avoiding the monthly cost of a leased line between your own sites
Fibre is still the first choice where it can be installed at reasonable cost, because it is unaffected by weather and has enormous capacity. Wireless wins on speed of deployment and where trenching or permits would be costly.
Point-to-point vs point-to-multipoint
A point-to-point link connects exactly two radios, with narrow beams aimed at each other. A point-to-multipoint system uses one base radio with a wider antenna to serve several remote sites. Point-to-multipoint is economical for many low-bandwidth sites around a central location; point-to-point gives the most capacity and reliability for a single important path.
What determines range and speed
Engineers plan a link with a link budget: a calculation of how much signal leaves one radio, how much is lost along the way, and how much arrives at the other.
- Transmit power and antenna gain. Larger dish antennas focus energy more tightly and reach further, but need more precise alignment and stiffer mounts. Transmit power and antenna gain are limited by regulation.
- Path loss. Signal weakens with distance, and higher frequencies lose more over the same distance.
- Obstructions. Buildings, terrain and trees in the path, or too close to it, cause loss. See the Fresnel zone and line of sight.
- Fade margin. The difference between the signal you expect and the minimum the radio needs. Margin absorbs rain, fog, ice and small misalignments.
- Channel width and modulation. Wider channels and higher-order modulation carry more data but need a stronger, cleaner signal. Most radios adapt modulation automatically as conditions change.
The practical result: short links at higher frequencies can carry very high throughput; longer links usually use lower frequencies and larger antennas, and trade some capacity for reach.
Frequency bands in brief
Links use either unlicensed bands, which anyone can use within the rules, or licensed bands, where a licence from Innovation, Science and Economic Development Canada (ISED) gives you a coordinated frequency. Unlicensed links are quicker and cheaper to set up but can suffer interference from other users. Licensed links cost more and take longer to approve but offer protection from interference. The trade-offs are covered in licensed vs unlicensed wireless backhaul.
Installation matters as much as design
Many link problems are mechanical:
- Mounts rigid enough that wind does not move a narrow-beam antenna off target
- Mounting heights that clear obstructions now and in future, including trees that grow
- Roof penetrations and attachments approved by the building owner and sealed properly
- Grounding, bonding and surge protection on outdoor equipment and cable runs
- Outdoor-rated cable and connectors with weatherproofing
- Safe roof and tower access, with fall protection and qualified climbers where needed
- Precise alignment, checked with signal readings at both ends
Roofs and towers are fall hazards. Antenna installation and alignment often happen at height. Work should be done by trained crews with a fall protection plan; see the fall protection hierarchy.
Running the link
Once installed, a link should be monitored like any other network component. Most radios report received signal level, modulation rate and errors. A slow decline in signal often points to a mount that has shifted or a new obstruction. Record the commissioning values so you have a baseline. For critical paths, plan a backup: a second link on a different band, a cellular failover or a carrier circuit.
A typical case: connecting a yard office
Consider an industrial site where a new yard office sits across a rail spur from the main building. Trenching under the tracks would need permits and time, so a wireless link is proposed. The planning usually goes like this:
- Define what the link must carry. A few computers, VoIP phones and security cameras in the yard office. Cameras set the capacity requirement, and phones set the need for low latency and steady performance.
- Check the path. From the main building roof, is the yard office roof visible with clearance above the rail cars, light poles and any stacked material in the yard? A site visit with photographs and a check of what may be built or stacked later matters as much as maps.
- Pick the band and antennas. For a short link with clear line of sight, a higher-frequency band can give high throughput with small antennas. If the area has many other unlicensed links, a licensed band may be worth the extra time.
- Choose mounting points. A wall mount on a parapet or a non-penetrating roof mount, with a route for the cable back to a network closet and a grounding point.
- Plan the backup. If the cameras or phones are important, decide what happens when the link is down: a cellular failover, or simply accepting that recording continues locally until the link returns.
- Install, align and record. Align both ends, confirm the received signal matches the design, and run a throughput test before the office moves in.
What the commissioning record should include
A finished link should come with a short record that anyone can use later to tell whether it has changed:
- GPS coordinates, mounting heights and azimuths for both ends
- Radio and antenna models, firmware version and configuration backup
- Frequency, channel width and, for licensed links, the licence details
- Designed and measured received signal level at each end
- Modulation rate and throughput test results at commissioning
- Photographs of mounts, grounding, cable entry and weatherproofing
- Monitoring thresholds and who is alerted when the link degrades
Compare monitoring data against these values after major storms and at least once a year, or more often for critical links.
How ehZee can help
Our point-to-point wireless service starts by asking what the link must carry and how important it is, then moves through a path survey, design, installation and verification of the finished link against the design.
Common questions
How far can a point-to-point link reach?
From a few hundred metres to many kilometres. Range depends on band, antenna size, terrain, mounting height and how much throughput and reliability you need. A path study gives a realistic figure for your sites.
Does snow or rain affect the link?
Rain mainly affects higher-frequency bands, and heavy wet snow or ice on antennas can reduce signal. A design with enough fade margin, and radios that adapt their rate, keep the link up through normal weather.
Is wireless secure enough for business traffic?
Modern radios encrypt the link, and the narrow beams are hard to intercept. Treat the link like any other network segment and apply the same security controls.