Industrial Wireless Point-to-Point Links Explained: Choosing Radios, Antennas and Network Equipment

Quick overview: This guide explains industrial wireless point-to-point links and the practical checks that help you understand and plan an installation. Use the contents below to go directly to the relevant section.

Point-to-point wireless links are used to extend Ethernet connectivity between two locations without installing a continuous copper or fibre cable between them. In industrial, mining, municipal, agricultural and commercial environments, they can connect buildings, remote plant areas, pump stations, security infrastructure, telemetry equipment and other networked systems.

A successful wireless link is not selected by distance alone. Line of sight, frequency band, antenna characteristics, interference, required throughput, mounting height, power, surge protection and the network interfaces at both ends all affect the final design.

This guide explains the main technical and purchasing considerations when selecting point-to-point wireless equipment.

What Is a Point-to-Point Wireless Link?

A point-to-point, or PtP, wireless link connects two fixed locations using a pair of compatible radios.

One radio is installed at each end. The radios form a wireless bridge so Ethernet traffic can pass between the two sites.

A typical link can therefore be represented as:

Local network → Ethernet switch → wireless radio )))) wireless path (((( wireless radio → Ethernet switch → remote network

The radios do not replace the entire network. They provide the wireless transport path between the two endpoints.

Common Applications

Point-to-point wireless links can be used for:

• Building-to-building network links
• Pump stations and reservoirs
• Boreholes and telemetry sites
• Mining and quarry infrastructure
• Industrial yards and warehouses
• Remote PLC or RTU networks
• Temporary project sites
• Agricultural facilities
• Campus networks

Wireless Bridge vs Wi-Fi Access Point

A normal Wi-Fi access point is generally intended to provide wireless access to client devices such as laptops, tablets and phones.

A point-to-point bridge is designed to create a fixed network link between two locations.

Although some wireless products support multiple operating modes, a customer requiring a building-to-building connection should specify a PtP bridge requirement rather than simply requesting Wi-Fi.

Line of Sight

Clear line of sight is one of the most important requirements for a reliable point-to-point link.

Buildings, terrain, trees, stockpiles, cranes and other obstructions can block or degrade the radio path.

Visual line of sight is important, but radio propagation also depends on clearance around the direct path.

What Is the Fresnel Zone?

The Fresnel zone is an elliptical region surrounding the direct radio path between the two antennas.

Objects entering this region can cause diffraction and signal degradation even when the antennas appear visually aligned.

For longer links, antenna mounting height may need to be increased to provide adequate clearance above terrain, buildings or vegetation.

A site survey or link-planning exercise is therefore preferable to choosing equipment only from the straight-line distance.

2.4 GHz vs 5 GHz vs Other Bands

Wireless equipment is available in different frequency bands. The appropriate band depends on the equipment, local regulatory requirements, interference environment, distance and required performance.

2.4 GHz can provide useful propagation characteristics but is commonly congested in populated areas.

5 GHz is widely used for outdoor wireless bridging and offers more channel options in many equipment families, but performance still depends on interference, permitted operating parameters and the specific installation.

Other bands and licensed solutions are available for specialised applications.

Always verify that the selected equipment and configuration are permitted for use in the country and application concerned.

Distance Is Not the Only Specification

A radio advertised for a long maximum distance is not automatically the correct choice for every shorter link.

Wireless performance depends on factors including:

• Transmit power
• Antenna gain
• Receiver sensitivity
• Frequency
• Channel width
• Interference
• Obstructions
• Fresnel-zone clearance
• Cable and connector losses
• Weather and environmental conditions
• Local regulatory limits

Quoted maximum distances should therefore be treated as product capabilities under specified conditions, not guaranteed performance at every site.

Throughput vs Link Rate

Wireless product specifications can quote radio or PHY rates that are higher than the actual usable network throughput.

Real application throughput is affected by protocol overhead, signal quality, interference, channel width, modulation, traffic direction and other conditions.

When requesting equipment, specify the actual network traffic requirement rather than relying only on the largest number printed on the radio specification.

How Much Bandwidth Is Required?

The required capacity depends on the application.

A telemetry link carrying small PLC or RTU data packets may require relatively little bandwidth. A link carrying multiple high-bandwidth data streams can require substantially more.

Other traffic such as VoIP, file transfers, SCADA, remote desktops and general network access should also be considered.

Where several services share the link, estimate the combined traffic and allow suitable headroom.

Latency

Latency is the time taken for data to travel across the network path.

For many monitoring and general network applications, a well-designed wireless bridge can provide suitable performance. Applications with strict timing, deterministic control or specialised real-time requirements need more careful assessment.

Do not assume that an ordinary Ethernet wireless bridge is a substitute for every deterministic industrial communications system.

Integrated vs External Antennas

Many outdoor point-to-point radios include an integrated directional antenna. Others use separate external antennas.

Integrated units simplify purchasing and installation because the radio and antenna are designed as one assembly.

External-antenna systems can provide more flexibility where a particular antenna pattern, gain, mounting arrangement or radio location is required.

Directional Antennas

Point-to-point links normally use directional antennas that concentrate radio energy toward the opposite endpoint.

Common antenna types can include panel, sector, dish and other directional designs.

For a simple two-site PtP bridge, the antenna at each end should be selected and aligned for the intended link rather than using a broad omnidirectional antenna without a specific reason.

Antenna Gain

Antenna gain describes how an antenna concentrates energy in particular directions relative to a reference.

Higher gain can support longer or more focused links, but it also produces a narrower beam pattern in many antenna designs, making alignment more critical.

Higher gain does not mean unlimited legal transmit power. The complete radio system must comply with applicable limits.

Beamwidth

Beamwidth describes the angular width of an antenna's main radiation pattern.

Narrow-beam antennas can reduce reception of unwanted signals from other directions and are useful for longer PtP links, but accurate alignment becomes more important.

Mounting structures must also be sufficiently stable to maintain alignment.

Polarisation and MIMO

Modern wireless bridges commonly use multiple radio chains and MIMO techniques.

Where separate antennas are used, antenna polarisation and orientation must match the radio design and manufacturer's requirements.

Incorrect antenna connections or orientation can significantly reduce performance.

Interference

Wireless links share spectrum with other transmitters. Interference can come from nearby access points, wireless bridges, industrial equipment or other radio systems operating in or near the same band.

A spectrum scan or site survey can help identify existing channel usage before final configuration.

In congested environments, selecting equipment solely by advertised range can lead to poor results if the interference environment is ignored.

Channel Width

Wider wireless channels can support higher data rates under suitable conditions, but they also occupy more spectrum and can be more difficult to use in congested environments.

Narrower channels can sometimes improve robustness or spectral efficiency for lower-bandwidth links.

The appropriate setting depends on the radio platform, required throughput and local RF environment.

Automatic vs Manual Channel Selection

Some wireless systems can automatically select channels, while others are commonly configured manually for fixed links.

For critical infrastructure, channel planning should consider neighbouring systems and site requirements rather than assuming an automatic setting will always provide the best long-term result.

PoE Power

Outdoor wireless radios are commonly powered using Power over Ethernet.

This allows network data and power to reach the radio through the Ethernet cable, simplifying installation at poles, masts and rooftops.

However, not all PoE is the same.

Before connecting equipment, confirm:

• PoE standard or voltage
• Required power
• Whether the device uses IEEE-standard PoE or passive PoE
• Injector or switch compatibility
• Cable requirements

Passive PoE vs IEEE PoE

Some wireless equipment uses passive PoE rather than standards-based IEEE 802.3af, 802.3at or 802.3bt power negotiation.

Connecting incompatible passive-PoE equipment can damage devices.

Never assume that a PoE-labelled radio can be connected to any PoE switch. Verify the exact input requirement.

PoE Injectors

A PoE injector adds power to an Ethernet connection so a remote device can be powered over the network cable.

Some wireless bridge kits include injectors, while others require them to be purchased separately.

Purchasing should confirm what is included rather than assuming the radio package contains all required power equipment.

Ethernet Port Speed

A wireless radio capable of high radio rates can still be limited by its wired Ethernet interface.

For example, a device with a 100 Mbps Ethernet port cannot deliver gigabit wired throughput regardless of a higher advertised wireless link rate.

Where high bandwidth is required, verify whether the radio provides Fast Ethernet, Gigabit Ethernet or another interface.

Copper Ethernet Distance

Standard copper Ethernet links have practical distance limits defined by the Ethernet standard and cabling system.

If the radio is mounted far from the nearest network switch or equipment room, the copper cable route must be considered.

Long outdoor copper runs also increase exposure to electrical surges and potential differences between locations.

Outdoor Ethernet Cable

Outdoor wireless installations should use cable appropriate for the environment and equipment.

Consider UV exposure, moisture, mechanical protection, shielding requirements, connector sealing and routing.

Indoor patch cable is not automatically suitable for permanent outdoor mast or rooftop installation.

Surge Protection

Outdoor radios and long Ethernet cables can be exposed to lightning-induced surges and electrical transients.

Suitable Ethernet surge protection, grounding and bonding should be considered as part of the installation according to the equipment manufacturer's requirements and applicable electrical practices.

A surge protector does not make an installation immune to direct lightning strikes.

Grounding and Bonding

Masts, enclosures, shielded cabling, surge protection devices and network equipment may require grounding or bonding depending on the installation design.

Incorrect grounding can create safety, surge and communications problems.

Site electrical requirements and manufacturer instructions should take precedence over generic assumptions.

Fibre at Wireless Sites

Fibre can be useful between an outdoor wireless termination point and the wider network, particularly where electrical isolation, long cable distances or high bandwidth are required.

A typical architecture might use:

Wireless radio → short protected Ethernet connection → industrial switch with SFP → fibre uplink

This combines the flexibility of wireless between sites with fibre distribution within the local infrastructure.

SFP Modules and Wireless Infrastructure

Industrial switches used at wireless endpoints can provide SFP slots for fibre uplinks.

The SFP must match the switch, fibre type, wavelength, connector and required distance.

Wireless equipment and fibre equipment should therefore be considered as parts of one network architecture rather than isolated purchases.

Industrial Ethernet Switches at Remote Sites

A remote wireless endpoint may need to connect several devices such as a PLC, RTU, HMI or other network device.

An industrial Ethernet switch can provide the local network fan-out and, depending on the model, managed networking, VLANs, fibre uplinks and PoE.

The switch port count and power requirements should be included in the site design.

VLANs Across a Wireless Bridge

Many transparent wireless bridges can carry VLAN-tagged Ethernet traffic, but this capability and configuration should be confirmed for the selected platform.

If several services such as automation and corporate data share the wireless link, VLANs can help maintain logical network separation.

Segmentation should be designed as part of the wider network and cybersecurity architecture.

Management Access

Wireless radios require configuration and ongoing management.

Management features can include local web interfaces, central controllers, cloud platforms, SNMP, logging and firmware management depending on the manufacturer.

For remote infrastructure, consider how authorised personnel will securely access and monitor both radios after commissioning.

Cybersecurity

A wireless bridge carries network traffic across a radio path and should be incorporated into the site's cybersecurity design.

Good practice can include:

• Strong administrative credentials
• Secure wireless encryption supported by the platform
• Restricted management access
• Network segmentation
• Disabling unused services
• Firmware updates
• Configuration backups
• Monitoring and logging

Default credentials and unnecessary public management exposure should be avoided.

Environmental Rating

Outdoor radios need suitable protection against the installation environment.

Check manufacturer ratings for water and dust ingress, operating temperature, humidity, wind loading and mounting conditions.

An outdoor-rated radio still needs correct cable entry, connector sealing, mounting and surge protection.

Mounting Hardware

Radios may be mounted on poles, masts, walls, towers or dedicated brackets.

Before ordering, confirm whether the required mounting hardware is included.

Consider pole diameter, bracket adjustment, wind exposure, antenna alignment and future maintenance access.

Wind Loading

Dish and panel antennas present surface area to the wind.

For exposed or elevated installations, mounting structures must be suitable for the antenna size, expected wind conditions and site engineering requirements.

Large high-gain antennas should not simply be attached to an unsuitable lightweight pole.

Link Redundancy

Where communications are critical, a project may require redundant paths.

Redundancy can involve a second wireless path, alternative frequency, fibre route, cellular connection or other network architecture.

Two radios mounted on the same structure and following the same obstructed path may not provide meaningful independence.

Point-to-Multipoint Is Different

A point-to-multipoint network connects one central site to multiple remote sites.

This requires different capacity, antenna and network planning from a simple point-to-point bridge.

If more than two locations must communicate through one wireless system, specify the number and positions of all remote sites rather than requesting multiple independent PtP kits by default.

Common Selection Mistakes

• Buying radios based only on maximum advertised distance
• Ignoring line of sight and Fresnel-zone clearance
• Not specifying required throughput
• Confusing radio link rate with usable Ethernet throughput
• Ignoring local interference
• Using the wrong frequency band
• Not checking Ethernet port speed
• Assuming all PoE is compatible
• Forgetting PoE injectors or power supplies
• Using unsuitable outdoor cable
• Forgetting surge protection and grounding requirements
• Not checking mounting hardware
• Ignoring antenna alignment and wind loading
• Not considering fibre or switching requirements at the endpoints
• Assuming PtP equipment is automatically suitable for point-to-multipoint networks

Replacing an Existing Wireless Link

When replacing existing radios, provide the manufacturer and exact model numbers from both ends if possible.

Also record:

• Link distance
• Mounting height
• Frequency band
• Antenna type
• PoE requirement
• Ethernet port speed
• Existing throughput
• Connected switches
• VLAN requirements
• Power arrangement
• Any central management platform

Changing radio platforms can require reconfiguration at both ends and should be planned accordingly.

A Practical Planning Checklist

For an accurate quotation, provide as much of the following information as possible:

• Application: ___
• Site A location: ___
• Site B location: ___
• Approximate distance: ___
• Clear line of sight: yes, no or unknown
• Approximate mounting height at Site A: ___
• Approximate mounting height at Site B: ___
• Required throughput: ___ Mbps
• Traffic/application: PLC/SCADA, general data or other
• Preferred frequency band if specified: ___
• Ethernet interface required: Fast Ethernet, Gigabit or other
• PoE available: ___
• PoE standard/voltage: ___
• Outdoor mounting hardware required: yes or no
• Surge protection required: yes or no
• Local industrial switch required: yes or no
• Fibre uplink required: yes or no
• VLANs required: yes or no
• Existing radio model if replacing: ___
• Quantity of links: ___

For difficult, long-distance or obstructed links, additional site information or a proper wireless survey may be required before final equipment selection.

For wireless enquiries, provide the link distance, site conditions, required throughput, line-of-sight information and existing equipment wherever possible. This helps narrow the requirement before equipment is quoted.

Technical Note

This article provides general purchasing and networking information. Wireless performance cannot be guaranteed from product specifications alone. Radio-frequency planning, local spectrum regulations, line of sight, Fresnel-zone clearance, interference, mounting, grounding, surge protection, network design and cybersecurity must be assessed for the specific installation. Manufacturer documentation, applicable regulations, site requirements and competent technical assessment take precedence.

Related catalogue examples: Commercial Wireless & Point-to-Point. For an equipment enquiry, contact Softcore Group Industrial Solutions at info@softcoregroup.co.za.