SXT LTE6 loses link

RouterOS Wireless Networking
1

Hi!
I’ve bought SXT LTE6 kit, set it up the same way as another one at my another place (no issues there for a half a year at all yet - turn on and forgot ), but with my new one there are a lot of LTE link loss issues. Especially at evenings and in nights.
I’ve noticed: the fist sign of problem is dissappearing of RSSI in interface info:

    pin-status: ok
  registration-status: registered
        functionality: full
         manufacturer: "MikroTik"
                model: "R11e-LTE6"
             revision: R11e-LTE6_V026
     current-operator: 25011
                  lac: 9011
       current-cellid: 198473729
               enb-id: 775288
            sector-id: 1
           phy-cellid: 276
    access-technology: LTE (CA2)
       session-uptime: 8m43s
                 imei: 356662100306072
                 imsi: 250110104447856
                 uicc: 8971100001044478569
         primary-band: B7@20Mhz earfcn: 2850 phy-cellid: 276
              ca-band: B7@20Mhz earfcn: 3048 phy-cellid: 276
                 rsrp: -68dBm
                 rsrq: -10.5dB
                 sinr: 23dB
                  cqi: 12
                   ri: 2

Just after modem reset (“AT+RESET”) RSSI is shown (-50 - -60dB), but then it disappears shortly. After RSSI disappeared LTE interface loses link in a while and modem often is in status “not searching”. After deactivation/activation of interface link goes up.
I have issues mostly in evenings and at nights - I suppose it correlates with cell/channel load.
I’d switched back to my old router+USB LTE dongle to check everything is OK with signal/cell and have had no link loss for 3 days (according to session uptime data from usb stick).
Full log attached.
A piece of log when an issue appeared:

18:21:50 interface,info lte1 link up
18:21:50 interface,info lte1 detect UNKNOWN
18:21:56 interface,info lte1 detect WAN
18:24:53 lte,async,raw SXTR__LTE: lte1: +CEREG: 1,"2333","0bd47801",9
18:24:53 lte,async,raw SXTR__LTE: lte1: +CREG: 11,"2333","0bd47801",9
18:24:53 lte,async,raw SXTR__LTE: lte1: $CREG: 11,"2333","0bd47801",9,"114"
18:24:56 lte,async,raw SXTR__LTE: lte1: sent AT+CFUN?
18:24:56 lte,async,raw SXTR__LTE: lte1: rcvd +CFUN: 1
18:24:56 lte,async,raw SXTR__LTE: lte1: sent AT+COPS?
18:24:56 lte,async,raw SXTR__LTE: lte1: rcvd +COPS: 0,2,"25011",9
18:24:56 lte,async,raw SXTR__LTE: lte1: +CEREG: 1,"2333","0bd4780c",9
18:24:56 lte,async,raw SXTR__LTE: lte1: +CREG: 11,"2333","0bd4780c",9
18:24:56 lte,async,raw SXTR__LTE: lte1: $CREG: 11,"2333","0bd4780c",9,"114"
18:24:59 lte,async,raw SXTR__LTE: lte1: sent AT+CFUN?
18:24:59 lte,async,raw SXTR__LTE: lte1: rcvd +CFUN: 1
18:24:59 lte,async,raw SXTR__LTE: lte1: sent AT+COPS?
18:24:59 lte,async,raw SXTR__LTE: lte1: rcvd +COPS: 0,2,"25011",9
18:25:09 lte,async,raw SXTR__LTE: lte1: +CEREG: 1,"2333","0bd47801",9
18:25:09 lte,async,raw SXTR__LTE: lte1: +CREG: 11,"2333","0bd47801",9
18:25:09 lte,async,raw SXTR__LTE: lte1: $CREG: 11,"2333","0bd47801",9,"114"
18:25:11 lte,async,raw SXTR__LTE: lte1: sent AT+CFUN?
18:25:11 lte,async,raw SXTR__LTE: lte1: rcvd ERROR
18:25:11 lte,async,raw SXTR__LTE: lte1: sent AT+COPS?
18:25:11 lte,async,raw SXTR__LTE: lte1: rcvd ERROR
18:25:19 lte,async,raw SXTR__LTE: lte1: +CREG: 0
18:25:19 lte,async,raw SXTR__LTE: lte1: $CREG: 0
18:25:19 lte,async,event SXTR__LTE: lte1: ^MODE:3
18:25:19 lte,async,event SXTR__LTE: lte1: +MSRI: 1
18:25:19 lte,async,event SXTR__LTE: lte1: +MPBK: 0
18:25:19 lte,async,event SXTR__LTE: lte1: *SIMDETEC:2,NOS
18:25:19 lte,async,event SXTR__LTE: lte1: +MMSG: 0, 0
18:25:19 lte,async,raw SXTR__LTE: lte1: +CGREG: 0
18:25:19 lte,async,raw SXTR__LTE: lte1: +CEREG: 0
18:25:19 lte,info lte1: not registred, state: 0
18:25:19 lte,info SXTR__LTE: lte1: not registred, state: 0
18:25:19 lte,async,event SXTR__LTE: lte1: +CPAS: 5
18:25:20 lte,async,raw SXTR__LTE: lte1: sent AT+CFUN?
18:25:20 lte,async,raw SXTR__LTE: lte1: rcvd +CFUN: 4
18:25:20 lte,async,event SXTR__LTE: lte1: *SIMDETEC:1,SIM
18:25:20 lte,async,event SXTR__LTE: lte1: *ICCID: 8971100001044478569
18:25:20 lte,async,event SXTR__LTE: lte1: *EUICC: 1
18:25:21 lte,async,raw SXTR__LTE: lte1: +CREG: 0
18:25:21 lte,async,raw SXTR__LTE: lte1: $CREG: 0
18:25:21 lte,async,raw SXTR__LTE: lte1: +CGREG: 0
18:25:21 lte,async,raw SXTR__LTE: lte1: +CEREG: 0
18:25:21 lte,async,event SXTR__LTE: lte1: *RADIOPOWER: 0
18:25:21 lte,async,event SXTR__LTE: lte1: *ADMINDATA: 0, 2, 0
18:25:21 lte,async,event SXTR__LTE: lte1: +CPIN: READY
18:25:21 lte,async,event SXTR__LTE: lte1: *EUICC: 1
18:25:21 lte,async,event SXTR__LTE: lte1: *ECCLIST: 5, 0, 112, 0, 000, 0, 08, 0, 118, 0, 911
18:25:22 lte,async,event SXTR__LTE: lte1: +MMSG: 0, 0
18:25:22 lte,async,event SXTR__LTE: lte1: +MMSG: 0, 0
18:25:22 lte,async,event SXTR__LTE: lte1: +MMSG: 1, 0
18:25:22 lte,async,event SXTR__LTE: lte1: +MPBK: 1
18:26:15 dhcp,info LAN-dhcp deassigned 192.168.9.240 from 7C:49:EB:9D:A9:F0
18:26:15 dhcp,info LAN-dhcp assigned 192.168.9.240 to 7C:49:EB:9D:A9:F0
18:26:19 lte,error failed to register on network
18:26:19 lte,error SXTR__LTE: failed to register on network
18:26:19 lte,account SXTR__LTE: lte1 session: 269s 6825731/879069 bytes 10783/6149 packets

Versions:

modem: R11e-LTE6_V026
OS: 6.48.1

mikrotik.log (65 KB)

failed to register a network
2

This “*SIMDETEC:2,NOS” means a SIM is Not Detected at slot 2.
You use a sim slot a or b ?
You can use “isopropyl alcohol” at sim card pins ?

And I know about one bug at lhgr who have 1xsim slot and RouterOS breake connection bcs he see missing sim at not exist slot 2… maybe this is the same bug.

You create a good post. Please write to support@mikrotik.com or use portal to create a ticket.

3

Thanks for help, SiB!
I’ve got in touch with support and upgrade modem firmware to next non-public version. It has been solved the issue.

4

Hello gen555
Could you share how you upgraded to next non public firmware version ? I wrote support but for 4 days still no answer. My problem is very similar to yours. And its getting worse and worse each day. Almost 2 disconnects every hour. Its very annoying.

5

R11e-LTE6 have 027 version of firmware now.
Only Support can share you a firmware file with 028.

6

The R11e-LTE6_V028 is now public available

7

Hello All!

I didn’t want to create a new topic, as my problem is almost identical as the OP’s, however - the difference is that the modem will never re-register itself after deregistering. The issue existed on ROS 6.48 with LTE firmware 028 and it still exists now on ROS 7.2.1 + LTE 033.

What I’ve noticed is that it happens when there’s no traffic via the modem for some time. If I’m working via the internet, during the day - it will never happen. But during sundays, if I’m not using the connection for few hours - the sim card deregisters.

My device is LGH LTE6 with CA. I also have a secondary (backup) modem which is SXT LTE kit v2 (it uses different provider). After switching the simcards between the devices - SXT works okay (althou it has veery poor reception), and the LGH deregistered after some time of inactivitiy. This proved that problem is with the device itself and not related to sim card/provider.

What’s odd - even USB Power Reset is not causing the sim card to re-register. I have to reboot the LHG completely (/system reboot). At the moment - i have a script running every 5 minutes that checks the status of LTE interface and if it’s not registered - it simply reboots the LHG, but it’s not solving my problem and is quite annoying.

Anyone, any idea?
Thank you in advance!

[EDIT]
Today, I did a USB Power Reset, but for a little bit longer time (7 seconds) and the card has registered again.