Question T-Mobile Home Internet (TMHI)

Tech Junky

Golden Member
Jan 27, 2022
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So, I looked into this late last year and never pulled the trigger on it but, now I've changed my mind and decided to go for it.

My phone tests at good speeds 600/100 or higher typically on 5G through a variety of TM MVNO's. The rep I spoke with to order service mentioned the location is considered "ultra high" for service which only confirms things further.

I read up on some things and watched some tubes on the equipment to gain some insight into the boxes being used and now there's a newer box being used from Arcadyan / 5G / AX / etc.

My plan because I can is to deconstruct it and amp things up a bit to see what it's really capable of on the modem level with external antennas. I have a few of them already from other WIFI projects so, it's not a huge issue to put something together. Might need to order some leads from Amazon but that should be maybe $5 to get the connectors outside of the plastic housing. I do have a card sitting around though that has 4 leads to SMA I could scavenge as well for this little experiment.

Ideally I'd like to rip the modem out of the box and put it into a PCI adapter and into my server to bypass the lack of networking control on the device. They really went BASIC on this thing with NAT / CGNAT / 2 Gig ports and absolutely no control over the nat / bridge options or anything really.

I couldn't find specific info on the modem inside whether it's mPCI or M2 or a router board so..... that's where ordering one and taking it apart comes into play.

Either way it's 50% cheaper than Comcast. I have 3 "towers" around me including the one on the roof of my building so coverage isn't an issue.

Gateway should be here in 2 days for a whopping $13 in shipping for expedited arrival. I want to get it in hand before my Comcast renews so I don't have to play the pay and then argue for a refund with them and end up waiting 6 weeks for a check in the mail situation.

TMO offered free 5-day / $9 3-day / $13 next day 2-day

Call took maybe 5 minutes... then again I'm like yeah, I do all that stuff to any question.

The reason for wanting to move the modem over to my server is a couple....
- gateway probably doesn't do LACP to bond Ethernet ports together if it doesn't have granular NAT settings
- one less thing to plug in / manage
- even though it's AX I get better results from my AP that's tuned and does 160mhz

Ripping the box apart shouldn't be too hard since it's a few screws and a few plastic clips to navigate around. If I new the format of the card though it would make life easier to order a PCI card now to have it show up when the box does. This should be a fun little adventure to play with though. If it hits the phone speeds or better life will be cake! If it doesn't then I'll make it either by fixing a bad design with different antennas or clone the IMEI to a better modem and pop the SIM into that instead.
 

Tech Junky

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This is key info:

Antenna Port Functions
  • Port M:
    • Frequency Range: 617-2690 MHz
    • Band Support(Download):
      • 4G: B2, B4, B5, B7, B12, B13, B14, B17, B25, B30, B41, B66, B71
      • 5G: n2, n25, n41, n66, n71
    • Band Support(Upload):
      • 4G: B2, B4, B5, B7, B12, B13, B14, B17, B25, B30, B41, B66, B71
      • 5G: n2, n25, n41, n66, n71
  • Port M1:
    • Frequency Range: 1710-5925 MHz
    • Band Support(Download):
      • 4G: B2, B4, B7, B25, B30, B41, B48, B66
      • 5G: n2, n25, n41, n66
    • Band Support(Upload):
      • 4G: B41
      • 5G: n41
  • Port M2:
    • Frequency Range: 1930-5925 MHz
    • Band Support(Download):
      • 4G: B2, B4, B7, B25, B30, B41, B48, B66
      • 5G: n2, n25, n41, n66
  • Port D:
    • Frequency Range: 617-2690 MHz
    • Band Support(Download):
      • 4G: B2, B4, B5, B7, B12, B13, B14, B17, B25, B30, B41, B66, B71
      • 5G: n2, n25, n41, n66, n71
These 2 connections are the key players for the bandwidth since M1/M2 are up to 6ghz which would be mmwave and the lack of channels would be slower connections. Though adding M1 to the mix might improve UL speeds if you're in an area using that band 41.

It's going to be an experiment to see if 2 antennas works as well as 4 when it comes to signals / bandwidth. It's kind of odd not to see UL/DL per connection though that wasn't mentioned in other sources. /scratching head/

On mu phones though finding band 71 is a priority because that's the 600mhz band that gives speed and distance when needed. The PCS bands for M1/M2 don't have much reach because of their spectrum signal being used. If you think of your home router and 2.4 vs 5 bands it's the same thing.

The 4 antennas though overall is 1/2 of what you find in your typical 5G handset. Though these antennas are much bigger in size in comparison it just means less chance for MIMO and CA being used due to the limited input/output on the modem.
 
Last edited:

VirtualLarry

No Lifer
Aug 25, 2001
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My plan because I can is to deconstruct it and amp things up a bit to see what it's really capable of on the modem level with external antennas.
I can see the FCC fines piling up now. Are you near an airport? They might consider you a "terrorist" if you do that, and it interferes with airplanes.
 

Tech Junky

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Jan 27, 2022
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No worries about any of those things @VirtualLarry

I'm not going going to modify the circuits on the modem just how it pulls in signals. Get it out of the plastic casing and move some connections around to optimal signal / bandwidth.
 

Muadib

Lifer
May 30, 2000
17,548
691
126
This might prove useful, as I was thinking about doing the same with either T-Mobile or Verizon.
 

Tech Junky

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@Muadib

NaterTater was a clue in ripping it apart and putting it back together with more oomph.


While he/they are recommending these hyper expensive MIMO exterior mounted antennas for ~$200-$400 supplementing it with just simple external options should suffice unless you have a really weak signal coming in and would have a benefit of exterior mounting something a bit more substantial.

https://www.amazon.com/dp/B07L5GPXCW - $20 and kind of ugly but 2 of them would connect to all 4 antenna outputs
https://www.amazon.com/dp/B09K63LQX3 -$37 for 2 antennas if you're going to transplant the modem into a different case

These 2 are pretty much the same specs w/ magnetic bases to hold them up in a window sill or on a table
https://www.amazon.com/dp/B06X3ZDKL9 - 5db
https://www.amazon.com/dp/B09WBFD7RJ - 6db

Also, there's one that supposedly does MIMO 4x4 w/ only 2 antenna leads...
https://www.amazon.com/dp/B07D93T1V9 - $50 / 2.5db - adhesive to stick it to a window or table / magnetic as well

The gateway should be showing up later today and I'm planning on ripping it apart to see if I can transplant the modem into my PC or an adapter to get rid of the nasty lack of config options and hijack it into just a modem w/o all the garbage incorporated into the box / OS. The videos only give a glimpse of what's inside the shell. The antenna connectors might be on a removable modem or part of a router board. There's not any good angles to view the guts of the gateway on any video I could find and of course there's no schematic I could find for the KVD21.

I think if I go external I will probably order 4 antennas to occupy the 4 ports on the modem and the puck @ $50 to see how they compare for performance. Whatever works better I keep and what doesn't goes back to Amazon for a refund.
 

Tech Junky

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So, I got the gateway and ripped it apart as much as I could before not being able to get the heat sinks off the Cellular side.

For the antenna's it's:

Black = WIFI
White = 5G

On the top there are 2 WIFI antennas
1654222266698.png

One side has #3
1654222303609.png

The other side has the 4th
1654222338947.png

I plan on disabling the WIFI because I have an AP feeding into my router/server and get great speeds w/o having to deal with this thing.
 

Tech Junky

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I uses a NANO SIM
1654222582313.png

The 5G / WIFI boards sandwich around a plastic spine in the middle
1654222636623.png

On the WIFI board you have 4 WIFI connections and a BT
1654222709480.png

Cellular side has the 5G + GPS connectors
1654222779711.png

5G in Red / WIFI not marked
1654222974043.png
 

Tech Junky

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Between the boards:

1654223023593.png

1654223040176.png

The white connectors come together outside of the plastic spine to join the 2 boards together.

To take it apart follow the video...

Remove 4 screws bottom
Remove top lid w/ screwdriver around the 4 corners
Remove 2 screws on top
Pry the sides from the bottom up / back comes off from front /. wedge from the front >> back to pop the tabs

If you want to get knee deep there's 6 screws on each board to remove / 1 of which is hidden behind the screen bracket
- remove the button panel to reveal the 2nd screw behind it that holds the bracket to the spine
 
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Tech Junky

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Knowing how this stuff works I'm going to attempt a few things to break into the OS and see what sort of things can be modified. There's the URL method but, there should be a serial method or ssh option to dig into it a bit deeper. I can't picture this being impossible to make changes on from a command line. Sire, they flash an image to it from the warehouse but, figuring out the flashing method is the key to unlocking things. There's obviously a reason why there's 2 USB-C ports and the Ethernet ports might be a way into it as well. My bet is on the USB ports letting you into the programming side. Of course it could be stupid simple and use a URL that's "hidden" to upload the image. It's just a matter of digging deeper than just prying it apart to add some better antennas.

If I get ambitious I might get some screw extractors to pull the heat sinks off and see if this is setup with a SOC or a module. If it's a module life would be better being able to port it over to a PCI card or USB board. There's no real need to SIM lock to the IMEI but, according to several sources they do.

I stumbled across some site that resells TMO / VZ / ATT data packages that mentioned getting a SIM from them and putting it into your own "router" / modem for the same $50/mo. I kind of wish I had come across that sooner. I might still venture into building my own box for this sort of service. IT's relatively simple to do and unleashing the raw power of the network would be nice. Though the guts of this thing should be able tohit 2.5gbps / 300mbps. The antenna issue is a place to start though since the PCB antennas are a bit on the small side. Though they're enormous compared to what's in a Phone.
 

Tech Junky

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Here's what I'm thinking for the 5G side of things.

Combine the 2 connectors for low band to 1 antenna and mid band to the other..

https://www.amazon.com/gp/product/B07SL285FQ - connect to each of the 5G sockets
https://www.amazon.com/gp/product/B091DQ3HGZ - combine the 2 SMA's into a single feed
https://www.amazon.com/gp/product/B074YXQYCP - connect to each antenna

IOW Connect M/D to one antenna and M1/M2 to the other since they use the same channels. ($40)

Otherwise skip the Y cables and run 4 antennas ($50)

Or just hookup M / D to their own antennas and skip M1/ M2 completely. ($30)

  • Port M:
    • Frequency Range: 617-2690 MHz
    • Band Support(Download):
      • 4G: B2, B4, B5, B7, B12, B13, B14, B17, B25, B30, B41, B66, B71
      • 5G: n2, n25, n41, n66, n71
    • Band Support(Upload):
      • 4G: B2, B4, B5, B7, B12, B13, B14, B17, B25, B30, B41, B66, B71
      • 5G: n2, n25, n41, n66, n71
  • Port D:
    • Frequency Range: 617-2690 MHz
    • Band Support(Download):
      • 4G: B2, B4, B5, B7, B12, B13, B14, B17, B25, B30, B41, B66, B71
      • 5G: n2, n25, n41, n66, n71


  • Port M1:
    • Frequency Range: 1710-5925 MHz
    • Band Support(Download):
      • 4G: B2, B4, B7, B25, B30, B41, B48, B66
      • 5G: n2, n25, n41, n66
    • Band Support(Upload):
      • 4G: B41
      • 5G: n41
  • Port M2:
    • Frequency Range: 1930-5925 MHz
    • Band Support(Download):
      • 4G: B2, B4, B7, B25, B30, B41, B48, B66
      • 5G: n2, n25, n41, n66
 
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Muadib

Lifer
May 30, 2000
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Here's what I'm thinking for the 5G side of things.

Combine the 2 connectors for low band to 1 antenna and mid band to the other..

https://www.amazon.com/gp/product/B07SL285FQ - connect to each of the 5G sockets
https://www.amazon.com/gp/product/B091DQ3HGZ - combine the 2 SMA's into a single feed
https://www.amazon.com/gp/product/B074YXQYCP - connect to each antenna

IOW Connect M/D to one antenna and M1/M2 to the other since they use the same channels. ($40)

Otherwise skip the Y cables and run 4 antennas ($50)

Or just hookup M / D to their own antennas and skip M1/ M2 completely. ($30)

  • Port M:
    • Frequency Range: 617-2690 MHz
    • Band Support(Download):
      • 4G: B2, B4, B5, B7, B12, B13, B14, B17, B25, B30, B41, B66, B71
      • 5G: n2, n25, n41, n66, n71
    • Band Support(Upload):
      • 4G: B2, B4, B5, B7, B12, B13, B14, B17, B25, B30, B41, B66, B71
      • 5G: n2, n25, n41, n66, n71
  • Port D:
    • Frequency Range: 617-2690 MHz
    • Band Support(Download):
      • 4G: B2, B4, B5, B7, B12, B13, B14, B17, B25, B30, B41, B66, B71
      • 5G: n2, n25, n41, n66, n71


  • Port M1:
    • Frequency Range: 1710-5925 MHz
    • Band Support(Download):
      • 4G: B2, B4, B7, B25, B30, B41, B48, B66
      • 5G: n2, n25, n41, n66
    • Band Support(Upload):
      • 4G: B41
      • 5G: n41
  • Port M2:
    • Frequency Range: 1930-5925 MHz
    • Band Support(Download):
      • 4G: B2, B4, B7, B25, B30, B41, B48, B66
      • 5G: n2, n25, n41, n66
You move fast!!! Keep it up, and thanks for the pics!
 

Tech Junky

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After a little more thought on the antenna subject I have a couple of different options I'm considering.

Might as well take advantage of all 4 ports on the gateway for maximum potential.

This expands things a bit.

Still need the pigtails to come out of the gateway - https://www.amazon.com/gp/product/B07SL285FQ - $8.50

I found some good reviews on some RP-SMA antennas from rednecks with trail cams, if anyone is good at backwoods engineering it's them.
https://www.amazon.com/gp/product/B08LTDZ7X9 - 2 pack x 2 - $18
Need RPSMA / SMA converters
https://www.amazon.com/gp/product/B08W1Z6XC4 - 2 pack x 2 - $17

Alternative puck like device / SMA / not adapter needed
https://www.amazon.com/gp/product/B07K7CDQ5W - $34

So,, prices being virtually equal it depends on the performance / aesthetic of keeping things tidy. The whole SMA/RPSMA things is just which side the pin in the connector sits on. Most devices for cellular use SMA and home routers use RPSMA.. .why? I guess it keeps people from just buying an antenna that works w/o the need for looking at the connector.
 

Tech Junky

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So, I started digging a bit more to figure out what antenna ports 4 & 5 are on the cellular side and stumbled upon this
https://www.reddit.com/r/tmobileisp/comments/saf05z
1654283427570.png

Doesn't really say what they're for but, I'm thinking about hooking up some antennas to them and see what it does with them.

Also states the modem is - Fibocom FG360NA https://www.fibocom.com/en/products/5G-FG360-NA.html

Looks like it's a SOC / LGA which wouldn't be able to ported over to an enclosure / PCI card so, that means no need for the screw extractors to pull the heat sinks off.

Chipset platformMT T750
Support SA/NSA,Support NR CA
5G Sub-6n2/5/7/12/14**/25/30/41/66/71/77/78
LTE FDDB2/4/5/7/12/13/14/17/25/26/29/30/66/71
LTE TDDB41/48/46
WCDMAB2/4/5
MIMO5G NR: DL 4×4 MIMO: n2/7/25/30/41/46**/48**/66/77/78
UL 2×2 MIMO: N41/77/78
LTE : DL 4×4 MIMO:B2/4/7/25/30/41/66

So, figuring out the optimal 4x4 setup to combine 5G / LTE could be interesting... shame the UL is 2x2 listed here but, that might be where those 2 extra connectors could come into play.

I think w/ the antennas I might keep the lid off and mount them to the array grill of the PCB antennas using a washer if the SMA don't stay put w/o one. Putting 4 antennas on top rather than using the long cables to put them on a window would be more optimal. Having the cables up to 6ft would be useful though too. I think there's enough space between the lid / chassis to run the pigtails out of the top vs the bottom. This also makes for the need to use longer pigtails which reduce the RF abilities due to resistance.

Maybe just unclip all of those PCB's and throw them into the box the gateway came with to reduce clutter inside the enclosure if I put it back together. I keep running across people selling / making stands w/ fans to properly ventilate the enclosure indicating there's a heat issue that produces stability / speed issues.

Not quite sure why the hell this thing needs BT / GPS though. Might disconnect those as well. GPS would be helpful potentially for moving vehicles to switch towers faster. /shrug/
 

Tech Junky

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Ordered the antennas / pigtails / adapters from #14 above and they should arrive tomorrow for testing. The only one that's a delay is the adapter to use the panel antennas. I still haven't even bothered plugging in the gateway at this point. I've got some ideas on how I want to setup the antennas either on the antennas cage with some washers / SMA connectors or zip ties to the corners of the cage since there's 90 degree bends on the panel antennas. The pucks are well, probably going to hang off the blinds on the windows or sit next to the gateway or magnetically to the table the gateway will sit on.

Also, another option is since the UFL connectors fit through the screw holes where the rubber feet go they could route through there and be a bit more sleek or put the gateway on its side and put the antennas on either end (top/bottom). I suppose the pucks could do the same keeping it compact and clean.

When looking at the antennas though I noticed the "LTE/D" / M / M1 are vertical and M2 is horizontal.
 

lakedude

Platinum Member
Mar 14, 2009
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Combine the 2 connectors for low band to 1
I wish I remembered Field Theory from Electrical Engineering better but this sounds like a no-no. You are taking what is already a weak signal and at best chopping it in half and that doesn't account for noise and reflections that could be introduced.
 
Last edited:

Tech Junky

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I wish I remembered Field heory from Electrical Engineering better but this sounds like a no-no. You are taking what is already a weak signal and at best chopping it in half and that doesn't account for noise and reflections that could be introduced.
Already moved beyond that idea and ordered 4 x antennas to play with. I already tossed that idea aside after thinking about it.

Once I power it up and start doing testing then it's onto the hacking of it to see if there's a way to reconfigure some of the defaults beyond just shutting off the WIFI.
 
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Tech Junky

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Plugged it in and fired it up.

The screen for some reason is just white but, the unit works just fine.

I thought maybe the white screen was a boot issue and reconnected all of the leads for WIFI / put the sim in and still had a white screen. Looked on my wifi analyzer and saw the SSID and just ignore the screen at this point, it's useless anyway.

Did some preliminary speed tests and was hitting 150 x 75 and then recalled the stupid converged SSID's issue... went in and switched that off and got up to ~300x75 just by doing that.

The wifi analyzer shows this thing outperforming signal wise my AP but, my AP does 160mhz and this look like it's doing 80mhz which is fine for the WAN but, internally would be a bit slow.

I'm going to have to dig into NT's scripts as they're throwing an error in PS for some reason.

Can't wait to test the new antennas though to see if I can gain some more ground to get the speeds up to where the phone hits ~600x100. It should make a difference being able to have all 4 antennas pointing in the right direction.
 

Tech Junky

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Got the pigtails & pucks installed but, while the reach of the cables is nice I think it's attenuating the signals a bit much. Speeds dropped ~30%. The monitoring app also dropped from the top level to one below it.

I figured out the screen issue... seems I got a bit heavy handed and the ribbon cable has a tear in it. No big deal don't need the screen anyway.

I hooked the pucks up with M1/D on one and M/M2 on the other. San

Out of curiosity I switched them around to pair up M/M1 for combined DL/UL and M2/D for purely DL. About the same for speeds.

Now, focusing on the M / M1 on separate antennas focusing on DL/UL only excluding the DL only. About the same speeds.

Paired up both low band M/D and M1/M2.Same speeds.

On average ~200DL/~60UL //\\ OEM ~300DL/~75UL

Looks like I'm hitting B2 - LTE / N41 - 5G

Gotta wait for Amazon tomorrow for the adapters to go in between the RPSMA and SMA pigtails. Considering this eliminates the cabling speeds should pick back up and hopefully be better quality signal. The pigtails have a decent amount of length but, to make things sleek about half the length would be good if routing them out the top of the gateway. (2.5"-3" )

If you wanted to run them out of the bottom though they're a good length to fish up the sides or through the foot holes where the screws were. Maybe not using the puck technique and spacing out the slabs will work better.
 

Muadib

Lifer
May 30, 2000
17,548
691
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Attenuation is my main concern. I bounce between 5G and 5G UW here at home, on my phone using Verizon towers. DL speed with 5G is in the low 200mbps range, and 5G UW is somewhere between 100-200 mbps above that. I'm hoping that you can improve your signal range to prove it can be done with positive results. I wish you well!
 

Tech Junky

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@Muadib Well, going from the top tier to one below with the long cables says something about the PCB antennas working well / designed well. Distance isn't really an issue considering how the OE / Phone pick up the signal strength pretty well and decent speeds. I have an OP 8 Pro that has all of the bands TM uses for this exact reason to make sure the bandwidth is there when it's needed. It's nice to use as a backup through the hotspot function or in the car to connect the MMI to for streaming / live data on maps.

I just think the gateway is leaving some speed on the table with its design and if it's not then I'll just put it back together the way it came and quit messing with it. The popular reviews for using external / outdoor antennas are the people in the middle of nowhere struggling to get even 20 x 1 out of their hotspot devices. They're happy to hit 50x10 at best. Coming from cable w/ gig service down to 1/3 of that is doable for 1/2 the price. I just have a tendency to max out the performance on tech things or at least try to before giving into the design that's presented.

I'm not going to deal with the Waveform 2x2 / 4x4 $200+ antennas for this sort of thing as I don't personally need them to get a signal. With the panel antennas though to keep stress off the UFL coax cables I'm thinking of mounting them all on top or 2 on top and 2 down the corners. I'll probably start with all 4 on top with 2 up and 2 @ 90 degrees on opposing corners. Depends on how I can rig them to the plastic securely. W/O the plastic outside parts in place mounting is kind of limited. Maybe some double sided tape will help at some point as well.

Yeah, VZW and UW is using mmWAVE which is high band / low distance. I tried their MVNO - Visible and while unlimited data it just didn't have bandwidth but, I paid for 3 months and got $100 back. In some spots I was struggling though to get 1mbps out of it. I even went to a store and put the sim into a VZW branded device and it still sucked. Now, with most MVNO's you get the same speeds as the native carrier typically. So far though I've used 3-5 different MVNO's with TM as the network and they all perform really well. I've since moved my number over to Google again to make switching easier for the best deals w/o having to deal with porting it from one carrier to another. Just take the sim out and put the new on in and it just works. Of course updating google to the new # on the phone so it knows where to send calls is a simple 2 minute SMS verification.

If I can get this gateway to work though at ~600 x ~100 I would be content not pushing for gig plus speeds. Tomorrow should give a little more insight with the different antennas w/o the cable. At least they should bring the speeds back to the OEM PCB levels. I have faith in the rednecks though as some mentioned using several different sets before picking these.
 

Tech Junky

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Got the paddles hooked up and tested. The only real difference was signal quality bax to the max like the PCB antennas. Speed did go up a fraction to 250x80. Not to be outdone I hooked up some cheap leftover WiFi antennas and got the same speeds. Though the WiFi antennas did drop a notch below in signal quality. I think it's stone to put it back together as it arrived and call it a day for boosting the speeds.
 

Muadib

Lifer
May 30, 2000
17,548
691
126
Got the paddles hooked up and tested. The only real difference was signal quality bax to the max like the PCB antennas. Speed did go up a fraction to 250x80. Not to be outdone I hooked up some cheap leftover WiFi antennas and got the same speeds. Though the WiFi antennas did drop a notch below in signal quality. I think it's stone to put it back together as it arrived and call it a day for boosting the speeds.
Thanks for giving it a good try.
 

Tech Junky

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Doing more testing in a different location away from the tower location and got 100UL. Going to retest everything. This is in the North side vs West where the tower is. There's also the TM station antennas on the roof on that side.
 

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