For those who follow everything about broadband speeds, Ookla published a recent article talking about the deployment of millimeter wave spectrum in U.S. cellular networks. You might remember the big burst of marketing in 2000 when Verizon commercials bragged about gigabit speeds on cellphones. These fast speeds were enabled by millimeter wave spectrum that had been deployed at the time in a handful of urban business districts. At the time, Verizon told investors that millimeter wave was going to be the future of cellular, and that cellular broadband was going to be able to compete head-on with cable and fiber networks. They had plans on the drawing board to deploy the technology deep in neighborhoods.

As a reminder, millimeter wave spectrum uses much higher frequencies than are normally used for cellular service. Before the Verizon marketing blitz, the company had purchased a lot of 28 GHz spectrum from Straight Path and XO Communications. That’s a significantly higher frequency than the mid-range spectrum (1 – 4 GHz) used for cellular service. It’s called millimeter wave spectrum because the radio waves for 28 GHz are extremely short. AT&T also dipped its toe into millimeter wave spectrum with the acquisition of 29 GHz spectrum.

The Ookla article points out that many of Verizon’s millimeter wave spectrum deployments are still in use, and the use of millimeter wave spectrum is growing. Ookla cites statistics compiled by its RootMetrics effort, where the company sends people to take random cellular speed tests in markets around the country. When those in-person tests are combined with the normal Ookla speed tests conducted by the public, the Ookla article shows that in the second half of 2025, that 2.2% of Verizon cellular speed tests used millimeter wave technology, while 0.2% of AT&T used the higher spectrum. T-Mobile had virtually no millimeter wave usage.

The report demonstrates the issues with using millimeter wave spectrum. The technology can deliver gigabit speed, but the effective distance from a transmitter is very short. RootMetrics found millimeter wave speed test connections mostly within 500 feet of a transmitter, even though the spectrum can theoretically carry for a half mile. That short distance limits the use of the spectrum to high traffic areas where the extra spectrum can help relieve pressure on the other cellular spectrum bands. In case you’re wondering, most high-end cellphones manufactured since about 2001 include the ability to receive the millimeter wave spectrum. Most of the rest of the world, other than South Korea, never activated millimeter wave spectrum in networks or cellphones.

Interestingly, this report also tells a similar story about C-Band spectrum (3.7 – 4.2 GHz). Most RootMetrics speed tests for connection using C-Band were found within a half mile from a tower, although the spectrum can theoretically carry for two miles. This is good proof that, while cellular speeds are improving, the fastest speeds are found relatively close to towers. The older spectrum bands used for cellular, like 700 MHz and 900 MHz, carry for many miles, but carry far less bandwidth.

The Ookla report goes into detail about the coverage found in a few markets. For example, the  report includes a map of millimeter wave just south of downtown Denver that shows small pockets of good coverage next to areas with poor coverage, again demonstrating the distance limitations on the technology. The report is well worth reading.