Perks of living in Kathy Neustadt’s Hilltop neighborhood in Denver include its sizable homes, wide-open city parks and proximity to Cherry Creek. But even in one of the city’s more expensive neighborhoods, residents still grapple with a problem faced by many Denverites: poor cell phone reception.

“Everyone in the area will confirm that the service around this area sucks,” Neustadt, 67, an AT&T customer, wrote in an email. “First world problems, but such a pain!”

Spotty cell phone reception plagues Denverites in seemingly random pockets throughout the city — making dropped calls and weak data signals a recurring annoyance. Much of the problem is caused by the Mile High City’s topography and landscape, experts say, with occasional hills and even trees affecting the reliability of users’ everyday cellular devices.

Dozens of people told The Denver Post about places where they consistently face trouble with cell service, including parts of the neighborhoods of Hilltop, Capitol Hill, Park Hill, Baker, Platt Park, Central Park and Green Valley Ranch.

“Wireless performance is very localized,” said Doug King, the director of business development at RootMetrics, an Ookla company that tracks mobile network performance. “It’s not so much that the Rockies impact performance in Denver as it’s the topography of the market,” with the Denver market’s terrain — including in the suburbs — varying between hills and flat land on the rolling plains.

Those environmental factors “all have an impact on coverage and propagation of the wireless signals across the market,” he added.

When Neustadt drives by Graland Country Day School in her East Denver neighborhood, her phone calls either cut out or drop completely. At home, the service quality is so poor that Neustadt says she sometimes travels farther around the block to avoid dropped calls.

“The way I have resolved it is by spending a ton of money to upgrade my Wi-Fi, so I can use Wi-Fi calling in my house,” she said. Although she’s called her carrier about the problem, it “made no difference.”

How the major carriers score

After conducting tests across 125 metropolitan areas nationwide for RootMetrics’ most recent Metro Area RootScore Report, the company found performance in Denver was around the national average, King said in an interview.

“Historically, Verizon has had the best performance,” he said.

In the city, Verizon trumps the other major cell carriers, T-Mobile and AT&T, for network reliability, network accessibility, call performance and overall performance. However, T-Mobile still beats Verizon and AT&T for network speed, data performance and text performance, the RootMetrics report indicates.

T-Mobile maintains a reputation for offering the most consistent quality of mobile network services throughout the rest of Colorado and across the United States, according to Opensignal’s latest USA Mobile Network Experience report. T-Mobile also ranked as the best in the state for video experience, 5G signal coverage, 5G signal availability, and download and upload speeds.

5G refers to 5th-generation mobile broadband, which the carriers installed in recent years to increase data speeds — often in the form of green-painted poles along neighborhood streets.

T-Mobile and AT&T both offer the highest proportion of time that users on their networks maintained a 3G, 4G or 5G connection in Colorado. Meanwhile, Verizon provides the most geographic coverage in the state’s populated areas for users on 2G, 3G, 4G and 5G connections, Opensignal reports.

Still, one T-Mobile customer, Ellen Wingenter, says she encounters little to no cell coverage when driving up Central Park Boulevard from East 35th Avenue to Northfield High School in northeast Denver, leaving her annoyed.

It “seems weird, with the bulk of the development in the Central Park neighborhood, that they wouldn’t have fortified cell coverage,” said Wingenter, 46.

T-Mobile, AT&T and Verizon respond

Over the last two years, T-Mobile has added 49 new cell towers and upgraded nearly 350 existing towers across Denver, said Lyssa Hansen, senior communications manager. The modifications are aimed at expanding the carrier’s 5G coverage, strengthening the performance of wireless networks and boosting its capacity “to keep pace with suburban and rural growth,” she added.

In the Baker neighborhood south of downtown Denver, Mark Tabor, president of the Baker Historic Neighborhood Association and a T-Mobile user, has seen new transmission poles — but they’re to no avail.

He described the service on his block as “variable, with frequent dropped calls.”

“Customers in the Baker neighborhood and northeast Denver can expect continued network improvements over the next year and into 2025,” Hansen said in an emailed statement. “T-Mobile covers nearly all of Denver with our Ultra Capacity 5G.”

Driving down Broadway, which borders Baker, AT&T customer Tom Dorsa says he loses cell phone connection when he passes the Chubby Cattle Denver restaurant, Mutiny Information Cafe and the Goodwill Archer Store, near Ellsworth Avenue.

Suzanne Trantow, AT&T spokesperson, said that, in addition to an area’s topography, the building materials and device type present in a given location can also impact signal strength.

Between 2020 and 2022, the carrier invested more than $550 million in wireless and wired network infrastructure throughout the state, focusing on an expansion of 5G capacity, Trantow said. In the Denver area, AT&T has added new cell sites, small cells and capacity additions.

Verizon spokesperson Lauren Peterson highlighted “a major multi-year transformation of its network, aggressively deploying 5G Ultra Wideband on more than 200 cell sites throughout Denver to extend coverage and capacity.”

The carrier increased its capacity on fiber-optic cables to move more data through its network and boosted bandwidth to its cellular network for new services, such as wireless internet service for homes and businesses.

It’s not just obstructions that degrade cell service, like leaves on trees or building walls. The size of an area and its population density also can affect signal quality. Verizon referred to Denver as a broader area for coverage, requiring hundreds of cell sites to provide sufficient service.

Where exactly a customer is making phone calls will affect their signal strength, too, with it degrading as they move farther away from the site, Verizon said.

For King at RootMetrics, the biggest contributor to service performance is the spectrum range available to the carriers.

“Your higher-spectrum bands are going to allow for higher speeds,” he said, but they won’t perform well farther away from cell towers.

For example, T-Mobile uses a mix of low-band and mid-band spectrums — the latter of which allows the company to offer high speeds. But other carriers that utilize lower-spectrum bands perform more reliably, King said, even if the speeds can be slower.

Ultimately, given the factors at play, King says he is impressed with the performance of Verizon, T-Mobile and AT&T in Denver. Each carrier scores well in testing categories, such as speed, reliability and data, King said, so “the performance of all three carriers in Denver is quite good” — even if customers run into spotty patches in parts of the city.

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