TMobile upgrade sites to 5G but on 3G backhaul?

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In a handful of areas, I notice TMobiles speeds vary wildly, even with plenty of spectrum, and what I would expect to be few users.

Case in point, a 'rural’ LTE on B4 with 20x20 on a colocated site will push 160Mbps alone.

TMobile sites in my area that are not on Colo or not on a building typically max out around 140Mbps with both B4 20x20 , B12 5x5 and B2 10x10 aggregated, while those that are Colo end up pushing well over 200Mbps., adding in B12/B71 will bring close to 300Mbps.  Only the colocated sites currently have been upgrade to 5G.

When I go out to other places, they appear to have upgraded some sites, but have capacity issues.  San Simeon, CA has been upgraded to 5G in April with B4 20x20, B12 5x5 and B71 10x10 as well as n71.  The issue is that regardless of day or night, you will have buffer issues, and be lucky to reach 0.5Mbps.  3G/2G were unusable.   Interesting enough, sites on either side were B4 20x20 only and typically no issue and seeing +120Mbps… of course they were.. Colocated.


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Did you ever figure anything out here?
I’m seeing pretty much the exact same behavior here (B66 LTE, when 5G enabled, but backhaul is going 3G, near-worthless), so that’s not weird.

I’m on a OP 8 Pro, and just about 4mi due North (slight NNE) of TMo main-HQ (in WA).

I was debating on asking them to send me a new SIM, but it sounds like that’d likely be a fool’s-errand.

Weird, that they’d want “5G indicating”, when the NR radio is at 0 dBm, and the LTE radio struggles (the front(haul) does okay, about 1/3 of if I go to <= 4G/LTE, but workable), but the backhaul is ridiculous, and sometimes just dies, on a test run…
OnePlus has a “use LTE balanced with 5G” setting, but this sure looks like a carrier-side deal…

Thanks for any insight, if you have any (I’m mostly back on non-5G now, because the battery drain is INSANE, when it’s searching like that, about 7%/hour overnight, I found out, a couple of nights ago).

What the heck are they doing, that the LTE-fallback is SO bad (3G on the backhaul, as you mention), particularly if the 5G signal is 0 dBm, you’d think the algorithm would just go for the full-LTE-balance side of things?


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Pretty much only some of the large/building macro sites near me have 5G/n71 and B71.

Out in San Simeon, it doesn’t matter what you’re connected to… its as if the entire site runs off an 10Mbps ethernet.   2G/3G ‘timeout’ on anything including speediest.  LTE - 0.5Mbps down / 6Mbps up is all you get - even with 20x20MHz AWS and 10x10 LTE B71 / 5x5 LTE B12 (should be capable of +200Mbps).  The site in town with 20x20AWS only is good for +140Mbps.

My phone isn't 5G, and until they deploy more 5G, there’s no reason to upgrade


I’m up in the greater-Seattle area, and my backhaul is fine, if I stay on LTE, ONLY.

If I go to 5G, my download (fronthaul) degrades a bit, perhaps 50-60%, and my ping times go WAY up, AND, my backhaul goes to almost zero (if I’m lucky I can get 0.5-1.0Mbps).

I don’t think TMo has provisioned this very well at this point, IMO/IME. If you’re on a 5G 0 dBm connection, I don’t get why they pass-through a solid (¾ bars) value, and then subsequently (this is my supposition part) cause the 4G/LTE to not fail-over, properly...

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T-Mobile is going to have to provide service in some remote areas if they want to compete with the Big 2 and that means they can’t always be as picky about backhaul as they’d like to be. Maybe, Starlink will provide some relief for these remote areas.

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I suspect that its less of a backhaul issue than the issue of your phone dsplaying 5G logo, connected to 5G service - far away vs. the site on 4G that’s right next to you.

I had similar issues when T-Mobile deployed B12 (700MHz) here, and a few instances of B71 with this as well.  This will occur until most sites are converted.

Eg.  The site ~2000’ away has B2/B4, and B12 was added 2 years ago.   The 4 other ‘nearby’ sites had already added B12, and being that it was ‘stronger’ and T-Mobile hadn’t set priority, it was picked up, and would not hand off until ~118 or worse dBm.  I could be in my driveway with 1 bar, and almost useless service unless I cycled airplane mode to have it connect - B2/B4 nearby.  T-Mobile changed the threshold to -116dBm , and problem solved.

I suspect that 5G will be similar .. if not worse initially in many areas.

If I set my phone to B71 right now… I drop to 1.5Mbps on the ‘good’ side, and < 1Mbps on the bad.. because its not close by with ~-113 to -116dBm in a good location.   There are times the my phone will hang onto B71 indoors w/o intervention.  Reset will bring it down to ~-100dBm, on B2/4/12 and ~100Mbps.

Since I don’t have a 5G phone yet, I’m only speculating.  As I don’t have any real need for one… I’ll wait, specs will get better, and price will come down.


Perhaps, but why does it “indicate at almost full-strength”, that’s pretty misleading, if you ask me.

If you’ve got basically a zero-5G signal, just enough to connect/ping, but that’s it, it would seem like it should indicate LTE, the “actual tower/radio”, that it’s using?  Plus, the performance shouldn’t fall off to 1/3/near-zero (down/up), right?

I think T-Mobile is doing something “fishy” here, personally, and I just need to figure out the right signal-tool, or perhaps go direct to ADB, to figure out what it’s “actually seeing”, in terms of connection.

The same way they’re “hanging onto” your B71, and nuking what could be a “decent B12 experience”, at your location, although in that case, it’s perhaps because the backhaul on the B71 tower is much better, so they’re rather steer devices there, who knows…

I walked about a 0.5mi radius around our place (all fairly dense suburban, all mapped as “excellent signal”, and all about 4mi due-N of TMo Main HQ, but I got more or less the same result.  This “we have 5G coverage for XX% of customers” is starting to look very, very sketchy, IMHO.

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Excellent signal on a map is different than excellent signal ‘quality’.

Eg.  In Fillmore, CA, it shows ‘excellent’ service, and there’s a ton of spectrum for me to use - however, signal ‘quality’ is/was the pits.  As a result, in a ‘best service’ area, I struggle around 1Mbps, with 3 channel carrier aggregation on LTE (20x20 B4, 15x15 B2 and 10x10 B71)… Signal to noise was ~0.5

Showing ‘NR 0’ is a little suspect here.  Since I don’t have a 5G phone (yet) I  couldn’t say.   I suspect that you’re really only connected to a 4G LTE site, as there’s no reading.  The current deployment of 5G with T-Mobile AFAIK, requires the ‘base band’ to be LTE, which would mean that you would be using 5G service when the 5G nr != 0 dBm…. or the tool is no good.   You need a proper diagnostics tool to determine what this is.

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Signal strength is not necessarily and indication of the speed one will get from a data connection. A congested 5x5 MHz band-12 carrier may have a strong signal but only enough spare capacity to send a SMS.

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modbot test post


only took two days to be able to post again..i call that improvement folks lol

thank all of yinz for putting that info out here,  a lot of fine points which are not commonly considered by many of us dunderheads…..all of these considerations are not for the faint of heart, or head.   Just to run a radical concept up the flagpole, wouldn’t it be great if T-Mobile had some kind of app which would tell you what was going on ? 

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Performance was still poor with 5g. Tickets filed and escalation to T-mobile OEM.