I've not used this particular device, but I have used Quectel GNSS modules, and they've been a surprisingly helpful company to work with. I'm a nobody, and working with Sony, Trimble, or ublox has been an exercise in frustration; you have to convince a salesperson that you're a big company and you can sell thousands of devices in order to just read the datasheet. This one does have some of the documents locked behind an access request, but in my experience, they've been very generous with those grants.
which is pretty good. Americans will want 4G bands B2, 4, 5, 12, 13, 14, 17, 20, 25, 26, 29, 30, 41, 66, and 71; this implements 9/15, it's missing bands 14, 17, 29, 30, 66, and 71. Those missing bands are either subsets or supersets of other bands (which could be interesting from a firmware perspective - will a tower with a band 66 antenna give this modem some of the central band 4 subset, or will it try to negotiate a channel that this can't access?), little-used ATT bands, or the 600 MHz T-mobile band 71, which has a wide rollout but poor device support.
My biggest question is, if I buy this phone today, with AT&T allow it on their network? My gut says no, they've been brandishing an ugly whitelist around for their big LTE push in February...
Nope, even before February they won't let you use the device, unfortunately. They're shutting down "incompatible" (non-whitelisted) devices and shipping out anything from $50 to used flagship replacements (pre-activated, so as soon as you receive the new one, your existing one will be shut off).
Unfortunately T-Mobile isn't a great option for this phone either, because the phone lacks band 71 (T-Mobile's only nationwide low-band). It may work well in some areas, but have no coverage in others. Verizon has a sort of pseudo-whitelist; you probably will have to activate a whitelisted phone and then swap the SIM, but it may work.
> will a tower with a band 66 antenna give this modem some of the central band 4 subset, or will it try to negotiate a channel that this can't access?
Here in the US (and likely in other places), carriers use MFBI[0] to solve this issue - it lets them broadcast both AWS-1 (as B4 and B66) and AWS-3 (as B66 only).
This first came into use when AT&T wanted to use B17 (Lower 700MHz blocks B-C) for their LTE network, rather than B12 (Lower 700MHz A-C). This prevented users from bringing their phones to smaller carriers (T-Mobile and US Cellular), who had significant 700A holdings. The FCC eventually pushed ATT to use both B12 and B17.
> little-used ATT bands
This phone likely wouldn't work on AT&T anyway - despite California's SB822 [1] forbidding it, they whitelist only specific devices on their network, and can go as far as soft blocking your account if you have one that is incompatible. I've linked the compatible phone list[2] below.
SB822's net neutrality provision has already been upheld in court (AT&T subscribers lost "data-free TV" on AT&T owned platforms because of it), but it remains to be seen whether other provisions (bans on tethering restrictions or device whitelisting, for instance) will be upheld as well.
That said, one nitpick I'd have is that these bands aren't necessarily "little-used" - B14 is FirstNet spectrum, and AT&T is currently rolling it out to a point where it reaches 99% of the population indoors. That's a strong commitment, and the band's support for HPUE means it can support coverage further than others at a similar frequency. B30 is WCS, which AT&T uses for capacity in a lot of places - but at 2300MHz it's not particularly useful for coverage. B17 is irrelevant due to MFBI and B29 is supplemental downlink (only useful for capacity).
It's important to think about the carrier aggregation combos that this device supports too - for folks who live in cities, carrier aggregation means a significantly more usable experience when the networks are congested. I don't see a supported list for that modem online, but it would depend on which are enabled in firmware anyway.
> 600 MHz T-mobile band 71, which has a wide rollout but poor device support.
As for T-Mobile; Band 71 is necessary in a lot of places, because they've been spectrum constrained for a long time. Until the 2017 auction for this 600MHz spectrum (which was rebanded from Digital TV service), they had no nationwide low-band holdings (unlike AT&T, who held many 850MHz Cellular licenses from decades ago, and Verizon, who won nationwide licenses to the 700MHz Upper C block in 2008). In 2015, they picked up licenses in the the Lower 700MHz range, mostly exclusive to A block - but they acquired almost none in US Cellular markets (much of the midwest, and parts of the northeast/northwest).
It's difficult to build out a network on midband alone - cell sites must be spaced far closer, and in-building coverage is very poor. This was one of T-Mobile's main limiting factors for a long time, and they didn't truly resolve it until that 2017 auction.
T-Mobile had a reputation for a long time for dropping service as soon as you entered a large building - this is why. Physics mean that lower frequencies are useful to telcos because they travel further, while higher frequencies are useful because they can carry more data.
The post-auction DTV transition wasn't short - it happened over 9 or 10 phases, which extended from 2018 until early 2020 (and were then extended again, due to the pandemic). This is part of why phones seem to have poor support - the 600MHz band is not widely used for cellular outside of the US and Canada even today, so it's common on popular phones made for those markets[3], but not in more niche devices like the PinePhone.
I've not used this particular device, but I have used Quectel GNSS modules, and they've been a surprisingly helpful company to work with. I'm a nobody, and working with Sony, Trimble, or ublox has been an exercise in frustration; you have to convince a salesperson that you're a big company and you can sell thousands of devices in order to just read the datasheet. This one does have some of the documents locked behind an access request, but in my experience, they've been very generous with those grants.
The modem supports the following bands:
which is pretty good. Americans will want 4G bands B2, 4, 5, 12, 13, 14, 17, 20, 25, 26, 29, 30, 41, 66, and 71; this implements 9/15, it's missing bands 14, 17, 29, 30, 66, and 71. Those missing bands are either subsets or supersets of other bands (which could be interesting from a firmware perspective - will a tower with a band 66 antenna give this modem some of the central band 4 subset, or will it try to negotiate a channel that this can't access?), little-used ATT bands, or the 600 MHz T-mobile band 71, which has a wide rollout but poor device support.