TECH

T-Mobile says its old LTE spectrum won't fix Starlink Mobile's indoor woes
SpaceX, the parent company of the Starlink low-orbit satellite constellation, has reached an agreement with Grain Management to acquire up to 14 MHz of spectrum in the 800 MHz band in the United States. The spectrum is intended for use by Starlink Mobile, the mobile service operation currently being structured by the conglomerate.
The deal with the investment firm remains subject to regulatory approval by the U.S. Federal Communications Commission (FCC). Financial terms of the transaction—announced last Thursday, the 8th—were not disclosed.
"This is the final critical piece of the spectrum puzzle needed for SpaceX to offer full cellular coverage across the United States," said Elon Musk, SpaceX's controlling owner, in a post on X.
The company has previously revealed plans to pair its satellites with terrestrial femtocells to provide 5G mobile coverage. SpaceX believes that the newly acquired low-band spectrum will resolve a crucial technical gap, paving the way for Starlink to operate as a mobile carrier in the United States.
T-Mobile, AT&T, and Verizon stock dropped when SpaceX purchased T-Mobile's former 800 MHz spectrum batch. This has been hyped as the last critical piece for Starlink Mobile becoming a rival fourth carrier, but T-Mobile isn't buying it.
T-Mobile spent years trying to get rid of the 800 MHz spectrum that it previously used for 4G LTE coverage but has no use for in the times of blazing 5G speeds and a "spectrum layer cake" approach to building out its network.
Grain Management bought the portfolio from T-Mobile in August 2026 for $2.9 billion, and SpaceX has now agreed to buy it for an estimated $8 billion, with up to 14 megahertz of paired spectrum on the table, pending FCC approval. While the stock price of T-Mobile, Verizon, and AT&T dropped on the news, as this piece of spectrum could potentially allow Starlink Mobile to offer indoor coverage, T-Mobile's CTO isn't having it.
The argument is that owning airwaves and running a carrier are two very different things. The 14 MHz portfolio is spectrum T-Mobile once ran as a single 5 MHz channel pair for LTE but sold it because it no longer fits its strategy since today's 5G Standalone and 5G Advanced networks use much wider channels.
Even with it, Starlink Mobile would hold roughly 80 MHz, and some of that is uplink only, while T-Mobile says it sits on nearly 400 MHz of low band and mid band spectrum. Moreover, a satellite hundreds of kilometers up faces about 50 dB more path loss than a tower a kilometer away. Dropping from 2 GHz to 800 MHz claws back only a few dB of that gap.
The whole reason this spectrum matters is indoor coverage, as wall penetration is the Achilles heel of signal beamed from space directly to cell phones like the Galaxy S26 Ultra that is discounted on Amazon, even if SpaceX equips Starlink dishes with femtocell gear. Saw points out that more than 70% of mobile traffic happens indoors, at home, at work, in shops, and at venues. Starlink's existing and planned DTC (direct-to-cell) satellite constellation is great for outdoor use, but a consistent indoor experience is a much harder job. So lower frequencies will likely help Starlink penetrate walls somewhat, but signal strength at the window and a usable connection in the living room are different things.
Even outdoors, T-Mobile calls satellite a complement to dense 5G networks, not a replacement, as a satellite beam covers an area that hundreds of terrestrial sectors serve today, and it could get ugly when thousands of people stream video in the same city. Saw also reminded that the US wireless industry has poured nearly half a trillion into infrastructure and spectrum auctions to build its 5G network, and it takes time, not just money.
While T-Mobile is defending its turf here and says it welcomes competition, SpaceX evidently intends to move fast, and the company has already shown it can surprise incumbents. With the launch of its massive V3 DTC satellites, Starlink Mobile will probably become a solid rural and fallback option, but it remains to be seen if it can be a real competitor in cities if it keeps acquiring relevant spectrum.
Outgoing T-Mobile CFO Peter Osvaldik categorically rejected the idea that SpaceX's Starlink satellite-to-smartphone service can be a serious competitor to its 5G network and is not convinced the company has a solid plan to do so.
Speaking at Citi's 2026 Global TMT Conference on Wednesday, he shot down the various ways Starlink has entertained taking on wireless carriers, which escalated with SpaceX's mega IPO this year, and ridiculed its slapdash approach.
"Imagine if we as a management team over the course of two months changed the strategy to how we're going to roll out a wireless network like a dozen times. You would laugh us out of the room and kick me out of the management team, appropriately so," he said.
Osvaldik pointed to the early notion that direct-to-device (D2D) connectivity from low-Earth orbit (LEO) satellites could replace terrestrial cellular networks. But basic physics rules out that scenario.
One of the limitations of satellite D2D is poor indoor coverage. Signals coming from satellites that are 350km above Earth lose strength by the time they reach handsets, so that the connection cannot penetrate buildings.
"The physics just don't allow direct-to-cell to be a substitute product ... You can't get through buildings, walls. You can't even get through a Tesla windscreen," said Osvaldik.
Another idea is to operate as a mobile virtual network operator (MVNO) running on a carrier's terrestrial network. Here, Starlink has met a wall of resistance from AT&T, T-Mobile and Verizon who are not open to an MVNO arrangement. They are also adamant that there is no so-called backdoor route via acquisition of another MVNO for regulatory reasons.
Building its own network is another option. But Starlink does not have the "path to the right level of spectrum assets," he said.
And then there's the femtocell strategy. This is the latest plan that "everybody in the know is laughing at and has betrayed the fact that there is no strategy there," he said.
SpaceX revealed during its first earnings call last month that it intends to compete directly with US wireless carriers using the spectrum it acquired from EchoStar to build a hybrid terrestrial-satellite network. The terrestrial part would be made up of rooftop small cells, an idea that has been widely criticised by wireless industry experts.
Osvaldik said T-Mobile estimates that it would take "over a billion femtocells to have the equivalent outdoor coverage with all the interference problems [and] backhaul problems."
"[Starlink] is not a competitive threat from a wireless perspective at all," he concluded.
Starlink still looms...However, when it comes to satellite broadband, it's a different story. Starlink broadband doesn't have the same challenges as mobile D2D because it uses "different spectral assets and external powered antennas."
Osvaldik downplayed the competition from Starlink for its 5G fixed wireless access and fiber, because the satellite operator is focusing on a different segment of the broadband market than T-Mobile.
"We're going to continue to see [Starlink] being successful going from the deep rural into suburban fringe, while simultaneously we're attacking from urban into more dense and midsized suburban," he said.
Verizon CEO Dan Schulman also dismissed Starlink's competitive threat in broadband and D2D, speaking at Goldman Sachs' Communacopia + Technology Conference on Wednesday.
"We've seen zero discernible impact on our broadband growth from any LEO satellite provider, including Starlink. The more I dive into the physics of satellite … the more convinced I am, whether it be broadband to the home or direct to device, that satellite is a complementary service … over the medium to long term, not a direct competitor. They just can't compete without a terrestrial network in urban and suburban," said Schulman.
T-Mobile has an exclusive partnership with Starlink for mobile satellite D2D services that lasts until at least the end of this year, and the carrier has not disclosed when the exclusivity expires.
The carrier has said that use of the mobile satellite service is very low, accounting for 0.0002% of its network usage.
T-Mobile along with AT&T and Verizon are considering working together to use satellite to fill rural coverage gaps. They agreed in principle to create a satellite joint venture to pool some spectrum resources and create a platform to engage with satellite operators. If they agree on definitive terms, the JV could be a model for keeping the relationship with satellite operators as a wholesale partnership and potentially head off direct competition.
T-Mobile argued that SpaceX’s acquisition of former 800 MHz LTE spectrum will not resolve Starlink Mobile’s indoor coverage limitations.
Key points of the debate:
• Wall penetration: Lower frequencies (such as 800 MHz) allow signals to pass through physical barriers better than high-band frequencies; however, a signal reaching a window is not the same as a usable connection inside a home.
• Capacity in dense areas: T-Mobile points out that a single satellite beam covers a vast area (currently served by hundreds of terrestrial towers), which could lead to bottlenecks and congestion if thousands of people attempt to stream video simultaneously in the same city.
• Network strategy criticism: T-Mobile and industry executives note that direct-to-cell satellites work well as a complement or outdoor emergency option, but they do not replace a dense 5G network or easily solve indoor coverage issues without massive terrestrial infrastructure.
• Partnerships and branding: T-Mobile even distanced its brand from Starlink regarding its T-Satellite service by removing direct mentions of Elon Musk’s company from certain official webpages.
by mundophone








