T-Mobile's new 600MHz network has been spreading like wildfire. The carrier says it has lit up more than 800 cities and towns with the new "extended range" Band 71 LTE, and that's changing the carrier's reputation for lacking rural coverage in much of America.

In cooperation with Ookla Speedtest and T-Mobile, we decided to see how real T-Mobile's claims are. We looked at Ookla's crowdsourced tests since March 1 to paint a picture of where T-Mobile users are seeing Band 71, and where you might need a new phone if you aren't.

Band 71 uses old UHF TV frequencies that are still being cleared by TV stations, but T-Mobile has been working with those TV stations to get them freed up more quickly than expected. Along with longer-range LTE, it's going to be the base band for T-Mobile's nationwide 5G network.

T-Mobile has a Band 71 coverage map feature on its website. It's fun and easy to use: go to maps.t-mobile.com, enter and zoom in on a town, and click the "See how coverage can improve" button. Toggling that on and off shows how life changes with a Band 71-capable phone.

Only a few phones are Band 71-capable right now, but T-Mobile pledges to offer more throughout the year. Unless you're using an LG G7, K30, or V30, a Samsung Galaxy S8 Active or S9/S9+, or a OnePlus 6, you aren't getting Band 71. If you're looking for a low-cost Band 71 phone, you'll probably have to hang out for a few more months until those are released.

Most of our Speedtest.net Band 71 sightings are in places where T-Mobile already had LTE; it just wasn't great. Take Omaha, Nebraska, for instance. There, T-Mobile had existing LTE coverage, but it didn't penetrate buildings well. People in that metro area will find Band 71 means they can use T-Mobile phones more reliably within buildings.

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We're definitely seeing T-Mobile LTE in cities that never had it before, though. Laramie, Wyoming, was a 2G town before Band 71 rolled in. We saw a half-dozen successful Band 71 speed tests there. Wheeless, Oklahoma, had no T-Mobile coverage at all east of town. Now it does. The same goes for Cedarville, California, and chunks of Port Orford, Oregon, all places we saw real-life tests.

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People in a few major cities should consider getting new Band 71 phones if they're frustrated with T-Mobile coverage. We saw improved results in the New Jersey suburbs of New York City, for instance. But mostly, the new network is being used to expand small-city and rural coverage—the places where T-Mobile needs it the most.

For more, take a look at our primer on Band 71, T-Mobile's official coverage tool, or Spectrum Gateway's map of service areas where T-Mobile can currently deploy 600Mhz. Below, see what we found.

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