Details
SCADA — supervisory control and data acquisition — is how a control centre sees and operates equipment spread across a region. The communication layer beneath it is what decides whether the system is trusted.
What the traffic looks like
Telemetry traffic is small, regular and intolerant of loss. An outstation reports a handful of values on a poll cycle; the centre occasionally sends a command back. Payloads are measured in hundreds of bytes.
That profile inverts the usual priorities:
| Office data | SCADA telemetry | |
|---|---|---|
| Bandwidth | High | Very low |
| Latency tolerance | Seconds | Bounded and predictable |
| Loss tolerance | Retransmit invisibly | A missed command matters |
| Availability | Business hours | Continuous |
| Site conditions | Building | Roadside cabinet, hilltop, pump house |
Specifying such a link by throughput is a category error. It is specified by availability, latency bound and the environment it has to survive.
Choosing the path
- Licensed narrowband radio — reliable, low running cost, your own spectrum, ideal for many outstations across a region
- Microwave links — where higher capacity or a backhaul aggregation point is needed
- Cellular — quick to deploy, per-site subscription, dependent on operator coverage
- Shared DMR infrastructure — telemetry alongside voice on the same repeaters, where the traffic budget allows
- Hybrid — primary and genuinely diverse backup, for sites where loss has consequences
Diversity has to be real. A backup link on the same mast, sharing the same power supply and the same backhaul route, fails at the same moment as the primary.
Where it is used
Water and wastewater — pump stations, reservoirs, treatment works, network pressure. Energy — substations, distribution switching, generation sites, renewables. Oil and gas — pipeline monitoring, valve stations, tank farms. Irrigation and agriculture. Environmental and flood monitoring. Traffic and motorway systems.
The common shape is many small sites, wide geography, no staff present, and a control room that needs to know now rather than tomorrow.
Site realities
Outstations sit where the process is, which is rarely where infrastructure is:
- Power. Frequently solar with battery, sized for the worst month rather than the average
- Environment. Temperature extremes, humidity, dust, and enclosures that have to survive them
- Lightning and surge. Exposed masts and long cable runs need genuine protection, not a token arrester
- Physical security. Remote cabinets are unattended and sometimes interfered with
- Access. A site that takes half a day to reach changes what "repairable" means
Security
SCADA networks were designed when isolation was assumed, and many still carry protocols with no authentication. Anything connecting them to a wider network needs segmentation, controlled access paths and monitoring. See firewall and network security.
What TechnoRF does
Path survey and link design, frequency planning and BTK licensing, equipment supply, enclosure and power design, installation, integration with the SCADA platform, and monitoring and maintenance of the communication layer. Get in touch with your site list and consequence classification.
Frequently Asked Questions
Why use radio when the site has mobile coverage?
Cost and control. A cellular subscription per outstation across hundreds of sites accumulates, and coverage at a remote pumping station is frequently marginal even where a phone appears to work. More importantly the operator network is outside your control: an outage or a congested cell during an incident is exactly when telemetry matters most. Many utilities run both, with radio primary and cellular as backup.
How much bandwidth does SCADA actually need?
Very little — often only a few hundred bytes per poll cycle. The demanding requirements are reliability and predictable latency, not throughput. This is why a narrowband radio link that would be useless for internet access is entirely adequate for telemetry, and why specifying SCADA links by megabits misses the point.
Can our voice radio system carry telemetry as well?
On DMR, yes, within limits. The standard supports data alongside voice, and telemetry from a modest number of outstations can share the infrastructure — which saves an entire parallel network. The limits are real: heavy polling competes with voice for slots, and a system carrying both must be sized for both. We calculate that budget before committing to a shared design.
What redundancy does a telemetry network need?
As much as the consequence of losing it justifies, and no more. A tank level that is read hourly tolerates a gap; a substation protection signal does not. The workable approach is to classify sites by consequence and give the critical ones a genuinely diverse second path — not a second link that shares the same mast, power supply and backhaul as the first.