Licensed vs Unlicensed Radio in Oil and Gas: Trade-Offs for Remote Telemetry
Choosing between licensed and unlicensed radio is really a choice about how much interference risk and administrative effort you will accept in exchange for cost and speed of deployment. Neither is universally better, and many mature networks use both.
Note for the reader: this article gives general industry background for US operators. Spectrum rules vary by country and change over time, so confirm current requirements with your regulatory counsel or a qualified frequency coordinator.
The basic difference
Licensed radio means you hold a license from the regulator (the FCC in the United States) for specific frequencies, at specific sites, under defined power and coverage conditions. Licensing generally gives you protection from harmful interference by other licensed users, and a legal path to resolve conflicts.
Unlicensed radio operates in bands where anyone may transmit with certified equipment, as long as it follows the technical rules for that band (power limits, modulation method, and so on). There is no site license and no exclusivity, and under the FCC's Part 15 framework an unlicensed device must accept any interference it receives and may not cause harmful interference to licensed users. Your protection from interference is the design of your equipment, not the regulator.
The common bands in telemetry
- Licensed narrowband UHF and VHF. Long used for SCADA, including the 150 MHz and 450 MHz ranges. They offer good propagation and penetration, narrow channels, and modest data rates, which is plenty for polling.
- Licensed MAS (Multiple Address Systems), in the 928/952 and 932/941 MHz band pairs (often referred to loosely as "900 MHz"). Designated for point-to-multipoint telemetry and control. It is popular in oil and gas because it pairs favorable sub-GHz propagation with licensed protection. Data rates are modest, and channels are coordinated.
- Licensed microwave (for example 6 GHz and 11 GHz point-to-point). For backhaul and high-capacity links between hubs, with coordinated paths and high reliability, and with rain fade as a real design factor at the higher frequencies (notably 11 GHz and up; 6 GHz is more rain-tolerant). 6 GHz remains the backbone of licensed point-to-point microwave, though it now also hosts coordinated unlicensed use.
- Unlicensed 900 MHz ISM (902 to 928 MHz in the US). Widely used for remote telemetry, with spread-spectrum radios that need no site license.
- Unlicensed 2.4 GHz and 5 GHz. Higher capacity, shorter reach, and much busier, with consumer Wi-Fi and many other devices sharing the space.
What spread spectrum does (and doesn't) do
Unlicensed 900 MHz radios use spread-spectrum techniques, mainly frequency-hopping (FHSS), with direct-sequence (DSSS) also defined. The idea is to spread the transmission across a wider piece of spectrum rather than sit on a single frequency. Frequency hopping jumps between channels in a pattern known to both ends, so a burst of interference on one channel costs you a retry rather than the whole link.
This makes spread-spectrum radios surprisingly robust in modest interference. It does not make them immune. When the band gets crowded, such as when multiple operators or an adjacent facility deploys many radios in the same area, throughput and reliability fall, and you have no regulatory recourse. Spread spectrum is a coping mechanism for a shared band, not a guarantee.
Trade-offs for remote telemetry
| Factor | Licensed | Unlicensed |
|---|---|---|
| Interference protection | Regulatory protection and coordination | None; engineering and luck |
| Time to deploy | Slower (application, coordination, approval) | Fast; buy, install, go |
| Up-front effort and fees | Higher (application, coordination, ongoing license maintenance) | Lower |
| Data rate | Often modest | Often higher |
| Predictability over years | Higher, since the band stays managed | Depends on who moves in nearby |
| Best for | Critical links, custody transfer, safety-related telemetry, large networks | Less critical sites, rapid deployment, short or secondary links, temporary builds |
A few practical points sit behind that table:
- Criticality drives the decision. The question to ask is what an outage on this link costs. Where the answer is a custody-transfer measurement, an ESD signal, or an unmanned site with no backup, the protection of licensed spectrum often justifies the effort. Where the answer is a redundant or low-consequence point, unlicensed is often fine.
- Interference risk is not static. An unlicensed band that is quiet today can be crowded in two years. A site assessment is a snapshot; it is not a warranty.
- Licensed does not mean fade-proof. Licensing protects against other users, not against terrain, weather, hardware aging, or antenna damage. A licensed link still needs margin and monitoring.
- Terrain and range matter as much as band. Lower frequencies generally travel farther and handle foliage better, which is why sub-GHz bands dominate long remote telemetry runs.
- Mixed networks are normal. Plenty of operators run licensed backbones with unlicensed spurs, or licensed primaries with unlicensed backup paths. The result is a multi-vendor, multi-band network that is harder to see as a whole than any one radio type.
- Compliance is an ongoing task. Licensed sites need their records, renewals, and coordination kept current, and equipment must be certified for the band you use.
A simple way to decide
- List each link by consequence of loss, not by distance alone.
- Assign critical links to licensed spectrum unless there is a strong reason not to.
- Use unlicensed where deployment speed or cost matters more than protection, and where a degraded link will not create a safety or measurement problem.
- Plan for the interference you cannot see yet: build margin, and watch the trend.
See your mixed licensed and unlicensed network in one view.
Aevus Comms (RF Link Intelligence) is vendor- and band-neutral in what it is meant to do: bring licensed and unlicensed, multi-vendor radio links into one read-only view so you can watch margin trends across the whole mixed network.
Related Articles
The band-by-band overview: VHF, UHF, MAS, ISM, cellular, satellite.
Why a weakening link still answers polls until it doesn't.
Ring topologies, PRP, HSR, and when each is worth the cost.
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