ITU Myth #1: Smallsats Are Limited to Just S-band and UHF

One of the most persistent misconceptions in the satellite industry is that small satellites are restricted to operating in S-band or UHF spectrum. This belief has become so entrenched that it often shapes mission design before teams even explore what’s truly possible.

Let’s be clear: this is a myth, not a rule; and it’s time we moved past it.

The ITU Doesn’t Care About Your Satellite’s Size

The ITU Radio Regulations make no distinction based on mass or volume. They classify spectrum use based on radiocommunication service type, not spacecraft size. Whether your satellite weighs 3 kilograms or 3 tonnes, the rules are the same.

Yet somehow, smallsat developers still tend to believe they must “stick to S band or UHF.”

Where the Myth Comes From

This myth is rooted in earlier realities that, while once valid, no longer reflect the state of today’s smallsat technology.

Historically, smallsats faced significant technical constraints. Their limited power budgets, thermal capacity, and antenna size made it challenging to operate reliably at higher frequencies such as X, Ku, or Ka band. These limitations naturally steered early developers toward lower-frequency bands like UHF and S band.

In addition, ground segment availability and compatibility played a role. UHF and S band were more commonly supported by existing ground infrastructure, making them the path of least resistance — especially for academic missions and the first wave of commercial smallsat operators.

But that era is over.

What’s Changed

Modern smallsats are far more capable than their predecessors, thanks to significant technological advancements across key subsystems.

The development of miniaturized high-frequency radios has enabled small platforms to operate in bands previously thought inaccessible. Similarly, the availability of efficient amplifiers and software-defined radios (SDRs) has improved signal performance while keeping power consumption manageable.

Deployable and steerable antennas have expanded communication options, making it feasible for smallsats to operate in higher frequency bands with narrower beamwidths.

Meanwhile, on-board processing capabilities have dramatically improved, allowing for smarter data handling and reduced dependence on ground infrastructure.

As a result, smallsats are now used in a wide range of operational roles, including Earth observation, IoT services, maritime traffic monitoring, and inter-satellite communications, in a variety of frequency bands beyond the traditional choices of S band and UHF.

Smallsats are no longer just educational tools or proof-of-concept missions. They are delivering real commercial services and therefore deserve spectrum access policies that reflect their capabilities.

Why This Matters

Holding on to the idea that smallsats must operate only in S band or UHF has several serious consequences.

First, it limits innovation, particularly for missions that require high data throughput or low latency.

Second, it creates bottlenecks by concentrating smallsat activity in just a few heavily used frequency bands, rather than distributing demand more efficiently across the spectrum.

Perhaps most importantly, this mindset undermines efforts to build sustainable and scalable smallsat businesses. Without access to a broader range of spectrum options, smallsat operators are constrained in how they grow, serve customers, and compete globally.

Let’s Rethink the Default

If you're designing a smallsat system, don’t assume your spectrum choices are limited. The constraints you face are the same as for larger satellites; and so are the opportunities.

With WRC-27 on the horizon, there’s no better time to explore how spectrum opportunities will support access to a wider range of applications and frequencies for all classes of satellites; not just the big ones.

At River Advisers, we can guide you through the relevant WRC-27 agenda items and help you understand their implications for your business strategy and future spectrum access.