Got it figured out!
It was all in the APN settings. I will put a screenshot in of what they look like in case anyone decides to use this with T-Mobile and they do a firmware update on the SXT LTE6.
Of course, I still am on the 7.3.1 version, but when I do an LTE Firmware Check it is running the latest in that. I do not believe that upgrading the ROS to v7.6 is going to change anything.
And what did I ask in the very first entry I made here ?
Good you got it figured out.
lol, yes, you asked about the APN. However, as far as I knew it was correct.
When talking with the guys at T-Mobile, I told them what I did to get it working, and he said he was just about to suggest what I did. He said he normally only see’s the issue with 5G devices. But for some reason, with the new LTE Firmware, the “auto” IP Type does not play nice - have to force it to IPv4.
Also, before the new LTE Firmware update, the “Use Network APN” box was checked and it worked on the default “internet” APN.
So all of this revolves around the new LTE Firmware update.
You are confusing RouterOS and routerboard firmware.
You are running os 7.6, but your routerboard firmware is still at 7.3.1
No offense meant, but I’m not confused about the two. I know fully how to check and upgrade both. Both are v7.6
I did try downgrading after I had upgraded, which maybe is where the thought of my confusion comes in. What I found is it did not matter if I downgraded either, the LTE modem firmware never changed.
Now, the LTE modem firmware was completely new to me. Everything about using Mikrotik for an LTE gateway was/is new. I’m positive it was the issue.
A new anomaly happened.
Got the new SXT LTE6 kit-US in. Went through all the steps as before. Upgrade the Router OS to v7.6, upgrade the RouterBOARD firmware to the same, upgrade the LTE Firmware, make sure the APN is set exactly like the other one. In fact, set everything but the lan IP address the same. Same across the board.
Yet again, after the LTE firmware upgrade and a reboot - no connection/internet. Actually, it would ‘connect’ to the tower, but it would not pull a proper IP address, just pulled a private 192.0.0.2 address.
I tried everything. Swapped out SIM cards. Went through ALL of the configurations to verify that it was all the exact same as the other identical SXT.
Figuring it had to be an APN issue once again, googled up T-Mobile’s APN’s. Found one that is for ‘older devices’ epc.tmobile.com - and that made it work.
So why would the same devices, running the same configuration/software/firmware, have to use completely different APN’s?
It has to be an issue with the LTE firmware for this device. It is the only thing that is causing this. I do not know anything about how all that works, but it has to be a bug right?
I get the same 192.0.0.2 address.
CGNAT ?
Makes sense then.
Update -
Been in contact with Mikrotik Support. They released a new LTE module firmware for it. Upgraded both of my SXT’s and now they both work great.
Fingers crossed the issue is resolved now, but huge props to Mikrotik for getting on top of this quickly.
Can you give more information about this LTE module firmware update? I can’t find anything about this anywhere. I’m trying to connect with this same model to AT&T and am getting nowhere!
So all they had me do is go in and update the LTE module firmware. After I contacted them they released a new update.
If you use winbox, go into the interface list and double click on the lte1 interface. The popup box will give you the option of “Upgrade Firmware” on the right hand side.
Once you have upgraded the firmware, if it still does not work, I would suggest contacting AT&T and making sure you have the proper APN set.
Hope that helps. I found Mikrotik Support to be very helpful, I wouldn’t hesitate to reach out to them also.
Thanks BWPWA - I tried that, but as I cannot make a connection - it can’t pull the update.
Maybe I can plug the eth1 into a PoE connection that is also an internet connection and it can then connect? I was hoping they just has a file to drop in the Files location in WinBox to get it to do the update. I looked for a while to try to find an update file for the LTE1 interface - but no luck.
Only way to update is through LTE connection AFAIK.
(which on itself is pretty limiting if exactly that lte connection is not working whereas the rest might be perfectly ok)
Contact support. Maybe they can give you an alternative way using drag/drop.
I’m beginning to wonder if the unit is not working right. It’s a bit unrelated to the post I suppose - but I’ll ask. Do the signal strength LEDs on the back of the unit light up - even it it doesn’t have a connection? Like when I was testing it earlier - I could do a Scan or Cell Monitor (forget which) and it would see signals on band B2 and B12 - one of them with -40 or so RSSI - but the signal strength LED indicators on the back of the unit never show anything. There are 5 bars there and none of them have ever lit up.
And another question - I know this is very directional - but like right now I’m testing it a different location and my cell phone has a couple of bars of signal - but running the Scan or Cell Monitor on this unit it is not showing anything. If there is cell signal at the location - even it I am not pointing at the source - should this unit “see” something? Or is it not picking it up as it needs to be pointing at the source? I have tried that as well - but still nothing on the Scan/Cell Monitor. There are definitely obstructions in the way - but my cell still gets some signal.
The 5 leds on the back are a signal strength indicator, when connected.
Do you have the possibility to use the SIM of your phone in that SXT ? Then you know for sure that SIM is ok (just be sure to search for the proper APN settings in advance).
If it connects, the device is ok.
If it doesn’t, you indeed do have other places to search for the problem.
And yes, it needs to be pointing roughly towards the source antenna which BTW might NOT be the one you think !
Use a tool like cellmapper.net or so to get an idea where that antenna should be for your provider.
The further that antenna is away, the more accurate it needs to be directed.
Signal on a cell phone can be subject to reflections from several places.
I have experienced the reverse for a vacation house we had in France.
ZERO (and I mean literally NADA) connection on a cell phone and pretty stable connection on my SXT device (mounted 4 meters up pointed as good as I could to a cell tower several km away).
I’m too scared to damage my cell phone sim. My phone is VERY central to my business operations.
I am thinking I might go to the local AT&T store and just get them to program a new sim for me for this device and try that route though.
I swear I had to do that with me last LTE device as moving the sim card over just wouldn’t work, but the new one fired up with no issues. But, I may be mixing up devices in my mind…
Its odd that they don’t have the LEDs light up to show signal even when not connected. I would think using the external LEDs to adjust the unit until LEDs were showing the best signal would come first - then try to make the connection by adjusting the settings.
Yeah, I know where the towers are here. So that’s not an issue. We only have 2 and I’ve been tracking them with LTE devices and mapping apps for a while to figure out what carriers are on them and what frequencies they are using, etc…
Thanks!
I could be wrong on the exact functioning of those leds but from what I recall, they only lit up when connection was made.
Connection can be made with pretty poor signal already.
So you may have to check again those APN settings first.
If your phone SIM is crucial to you (which I understand), maybe reverse the action ? Put the SXT SIM in a phone and see if it connects. Most people do have some older phones lying around in a drawer somewhere 
At least you will have a better idea where the problem might be situated.
This is the closest I could find describing the led function.
https://help.mikrotik.com/docs/display/ROS/LEDs#LEDs-WirelessSystems
It mentions modem-signal but that still leaves the question unanswered if that means connected or not. For my logic it should be connected since radio is not modem. Modem = data = connected. My view.
It is clear that it is not clear, that’s for sure.
Thanks - I appreciate the effort. Clear as mud docs are always fun!
Too many companies just don’t have any usage detail in the docs anymore. Here are LEDs. Here are 1000 settings - but little explanation about what they do or how they work together.
I’m not bashing Mikrotik - they do it too - but pretty much all manufacturers any more do that. I do like Mikrotik videos on how to do things with their devices - that is nice - but still too often too MUCH detail is left without discussion.
Surely they have done testing with many cellular carriers - it would be nice if they would put out docs with what settings they used that were successful!
I used a CLI setting to turn on logging for the lte interface as well - and there is a lot in the logs - but I have no idea what the information is telling me - nor any idea of where to find out what it means. The poor support at AT&T would surely not know what the data in the logs mean - they were fully confused about IP versions, authentication settings, and even what the APN should be set to.
Standard practice anymore seems to be to just turn it on and start doing stuff until it works!
Try to search for posts from user Sib, dancing panda.
He has got some scripts and good pointers to log lte issues and possible causes