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T-Mobile's satellite messaging put to the test: Here are the resultsT-Mobile's satellite messaging put to the test: Here are the results
T-Mobile is offering satellite messaging services through 477 satellites operated by SpaceX's Starlink. Now, Signals Research Group (SRG) is putting that new offering through its paces.
Mike Dano / Light Reading
February 27, 2025
1 Min Read
Source: Jose Luis Stephens/Alamy Stock Photo
Wireless network research company Signals Research Group (SRG) published some of the results from its recent tests of T-Mobile's new satellite messaging service, running through SpaceX's Starlink satellites.
The firm highlighted a few noteworthy takeaways:
The connections are 4G LTE, not 5G.
They run over a tiny slice of T-Mobile's spectrum holdings: 5MHz of spectrum in Band 25 (1952.5MHz).
There's very little delay between the messages being sent and received. According to SRG, "in many cases, the delivery time was largely comparable to a terrestrial text messaging service. In a few instances, the delivery time wouldn't suffice if the text message read, 'Help, a Grizzly bear is chasing me,' but if that is what the message reads, then the sender's days on earth are already numbered."
There doesn't appear to be much interference between SpaceX's satellites and T-Mobile's terrestrial cell towers – an early concern in the sector. "I decided to really stress test the service from inside my house, a mere 1.5 miles from the nearest T-Mobile cell site, which offers great Band n25 5G coverage (e.g., the same exact radio channel used by Starlink)," SRG's Michael Thelander wrote on social media. "Despite the 40-45 dB difference in signal strength between Starlink (LTE) and 5G in the same 5MHz channel at my house, the messages always got delivered / received, even when placing the phone on a basement stairway banister located in the middle of my house."
The findings are important because SRG conducts its tests using professional wireless network testing equipment from the likes of Rohde & Schwarz and Accuver. Indeed, the firm has a lengthy history of running detailed networking tests on emerging wireless technologies, from open RAN to dynamic spectrum sharing.
To read the complete article, visit Light Reading.
