SXT LTE6 kit - instable connection / lost internet

RouterOS Wireless Networking
1

Hi all,
new user of forum and Mikrotik hardware, but have been lurking around and found a lot of useful info in Wiki and forum.
I just recently bought and installed an SXT LTE6 kit, I have it installed inside the house high up in the attic.
Distance from cellmast is 970 meters, terrain-profile shows I should have free line of sight, possibly with buildings and tree blocking slightly.
I have the unit mounted with centerline directly to tower, give or take a few degrees.

I know I would probably get a better signal if mounted outside, but I am unable to get to the ideal mounting posistion because it is so high up.
From monitoring signal strength I believe current location will do, with RSRP=-90dB, RSSI=-58dB, SINR=7dB.
The wall is an uninsulated wood wall, so shouldn’t block too much signal.
With this signal I am able to get around 60Mbit/s down and 20Mbit/s up, which is sufficient for me (sometimes its better, sometimes worse).

I have upgraded RouterOS to latest 6.47.7 (stable), and was running at modem firmware R11e-LTE6_V025.
Notice yesterday that there was a new modem firmware R11e-LTE6_V026. Installed this new firmware, but it didn’t seem to resolve the problem.

I am posting this because I have a problem in that my internet connection is not stable. I have noticed this all since I first installed it, but first thought I had it pointing wrong direction etc.
But I now wonder if there is a problem with hardware or firmware/software in my device.

I am located in Norway. My provider is Telenor, and I have the APN configured as telenor.smart.

I will give an example of what happens:
Yesterday night before I went to bed I had very good performance, about 55/19Mbit/s.
When I arrived home after work this afternoon I was unable to connect to internet.
I did a reboot of the device, and service was back up.

It then worked for an hour or two, before it stopped again.

I have previously noticed that I have had varying performance, where I seem to be moving between bands and cells.
So with info found on this forum and Seans forum at https://confusedbird.com/ I have tried to lock to a cell/band using at-chat commands.

I checked for a while before I decided Primary band B3@20Mhz seemed to give me best performance, with CA-band B8@10Mhz.

I accomplished thsi with the following command:

[admin@MikroTik] > /interface lte at-chat lte1 input="AT*Cell=2,3,,1450,3" 
  output: +CREG: 6,"7b0d","01166b07",7
$CREG: 6,"7b0d","01166b07",7,"15c"
+CEREG: 1,"7b0d","01166b07",7

[admin@MikroTik] > /interface lte info lte1 once                           
           pin-status: ok
  registration-status: registered
        functionality: full
         manufacturer: "MikroTik"
                model: "R11e-LTE6"
             revision: R11e-LTE6_V026
     current-operator: 24201
                  lac: 31501
       current-cellid: 18246405
               enb-id: 71275
            sector-id: 5
           phy-cellid: 3
    access-technology: LTE (CA2)
         primary-band: B3@20Mhz earfcn: 1450 phy-cellid: 3
              ca-band: B8@10Mhz earfcn: 3750 phy-cellid: 93
                 rsrp: -90dBm
                 rsrq: -9.5dB
                 sinr: 3dB

Will continue in next post…

Edit: Added OS and firmware versions

low signal SXT LTE6
Initial connection SXTR T-Mobile US
2

When performance degrades or internet is lost, I notice I am no longer running with Primary Band + CA, only Primary.
And Access-technology has gone from LTE (CA2) to Evolved 3G (LTE):

/interface lte info lte1 once 
           pin-status: ok
  registration-status: registered
        functionality: full
         manufacturer: "MikroTik"
                model: "R11e-LTE6"
             revision: R11e-LTE6_V026
     current-operator: 24201
                  lac: 31501
       current-cellid: 18246405
               enb-id: 71275
            sector-id: 5
           phy-cellid: 3
    access-technology: Evolved 3G (LTE)
       session-uptime: 3h13m25s
         primary-band: B3@20Mhz earfcn: 1450 phy-cellid: 3
                 rssi: -60dBm
                 rsrp: -91dBm
                 rsrq: -9dB
                 sinr: 7dB

To fix this I would either reboot the device or run /interface lte at-chat lte1 input=“AT*Cell=0”

Any advice on how to proceed in troubleshooting/fix this issue would be greatly appreciated!
Please let me know what more info I need to supply.

Best regards,
Jens


Update:
I have seen that peeople have been asked to supply cell-monitor informations, so here we go (after first unlocking with at-chat):

[admin@MikroTik] > /interface lte at-chat lte1 input="AT*Cell=0"           
  output: +CREG: 6,"7b0d","01166b05",7

[admin@MikroTik] > /interface lte cell-monitor lte1                        
PHY-CELLID BAND                      PSC EARFCN                 RSRP          RSRQ          RSSI         SINR
       126 B3                                            1450                        -97dBm         -15dB
       128 B3                                            1450                        -93dBm         -10dB
       348 B7                                            3050                       -100dBm         -11dB
       349 B7                                            3050                        -99dBm       -15.5dB
       350 B7                                            3050                        -95dBm       -13.5dB
       373 B3                                            1450                       -105dBm       -19.5dB

[admin@MikroTik] > /interface lte cell-monitor lte1 duration=60  
PHY-CELLID BAND                    PSC EARFCN                   RSRP          RSRQ          RSSI         SINR
         5 B3                                              1450                      -104dBm       -19.5dB
        38 B3                                             1450                      -105dBm       -19.5dB
       126 B3                                            1450                        -95dBm       -13.5dB
       128 B3                                            1450                        -91dBm        -9.5dB
       194 B3                                            1450                        -97dBm       -19.5dB

There are some other cells showing up and disappearing, is there a way to keep everything it finds instead of blanking?
Jens

Update:
Checked today at lunch after leaving cell-selection open overnight.
Got good down/up-speed at 58.58/13.66Mbit/s and ping at 34ms. interface shows:

[admin@MikroTik] > /interface lte info lte1 once 
           pin-status: ok
  registration-status: registered
        functionality: full
         manufacturer: "MikroTik"
                model: "R11e-LTE6"
             revision: R11e-LTE6_V026
     current-operator: 24201
                  lac: 31501
       current-cellid: 18246412
               enb-id: 71275
            sector-id: 12
           phy-cellid: 221
    access-technology: LTE (CA2)
       session-uptime: 14h23m29s
         primary-band: B7@20Mhz earfcn: 3248 phy-cellid: 221
              ca-band: B7@20Mhz earfcn: 3050 phy-cellid: 350
                 rssi: -70dBm
                 rsrp: -99dBm
                 rsrq: -6dB
                 sinr: 16dB

I have been connected this cell 18246412 before, but it has showed very varying performance, that is why I selected to try to bind to 18246405.
May have to take a step back and reassess, must admit I find it difficult to keep the head clear on what is happening… :slight_smile:

Jens

3

A bit odd that the signal strength (RSSI) is so high compared to SINR / RSRP which are far from optimal considering the proximity to the mast. This might indicate the unit is misaligned or there are objects like trees or buildings the dampers the signal.

B3 (1800Mhz) is a good choice but requires line-in-sight with no obstacle in between. Try to put the device at high as possible preferable on top of the roof using mast pipes. If you for some reason are unable to get a clear line-in-sight, pick the lower band B20 (800 Mhz) for a more stable signal.

When you have achieved a sufficiently stable signal, you can start adjusting specific options like carrier aggregation and cell lock.

Some useful hints regarding the various signal indicators: Mobile Signal Strength Recommendations

4

Thanks for taking the time, Larsa.
At least for now I don’t have the option of moving higher up, and I have tried my best using maps and compass to get the alignment correct.
Buildings and trees are likely to be in the way, yes.
I had a look at the info in the link you supplied, and I have seen most of it before, but a very useful reminder.
When I installed/aligned, I paid most attention to RSRP and SINR, while at the same time trying to keep RSRQ in my sidevision :slight_smile:

So to your suggestion:
I tried allowing only b20 (in webfig -lte1).
But result is not good, with DL of 4.86Mbps and UL slightly better at 12.91Mbps.
Here is the current info:

[admin@MikroTik] > /interface lte info lte1 once 
           pin-status: ok
  registration-status: registered
        functionality: full
         manufacturer: "MikroTik"
                model: "R11e-LTE6"
             revision: R11e-LTE6_V026
     current-operator: N Telenor
                  lac: 31501
       current-cellid: 18246400
               enb-id: 71275
            sector-id: 0
           phy-cellid: 27
    access-technology: Evolved 3G (LTE)
       session-uptime: 1m27s
         primary-band: B20@10Mhz earfcn: 6400 phy-cellid: 27
                 rsrp: -80dBm
                 rsrq: -11dB
                 sinr: -2dB
                  cqi: 7
                   ri: 2
[admin@MikroTik] > /interface lte cell-monitor lte1 duration=60 
PHY-CELLID BAND                                                          PSC EARFCN                                                                  RSRP          RSRQ          RSSI         SINR
        52 B20                                                               6400                                                                  -90dBm       -19.5dB
       166 B20                                                               6400                                                                  -93dBm       -19.5dB
       321 B20                                                               6400                                                                  -86dBm         -18dB
       323 B20                                                               6400                                                                  -82dBm         -15dB


[admin@MikroTik] > /interface lte cell-monitor lte1 duration=60 
PHY-CELLID BAND                                                          PSC EARFCN                                                                  RSRP          RSRQ          RSSI         SINR
        29 B20                                                               6400                                                                  -95dBm       -16.5dB
        52 B20                                                               6400                                                                  -89dBm       -19.5dB
       166 B20                                                               6400                                                                  -94dBm       -19.5dB
       321 B20                                                               6400                                                                  -86dBm       -18.5dB
       323 B20                                                               6400                                                                  -83dBm       -13.5dB

As a test, should I try to lock to one of the other cells, or is that a waste of time?
Edit: Also: Shouldn’t I be able to get CA2 on 800Mhz

5

I have 3 towers to choose from from my house.
I chose the current one because it was the closest. Its at 147degree bearing at a distance of about 970meters.
Drawback with this tower is that there is likely a lot of buildings and trees, as well as more people around it, being located in the village center.

The two other towers are further away, at about 2200 and 2300 meters (bearing north for one and north-west for the other one - roughly).
They are both located in areas of industry, so there are less people around them - particularly at night.
There are buildings of course, but I think terrain might help me a little.
My question:
Will the more than doubled distance to tower be neglible, so I should do further tests with those two other locations?

LineOfSight current location - with points being lifted up to real height above ground shows the line clear of terrain by 5-6meters.
But of course there are houses and trees that I am unable to calculate, but taller than that..

6

It looks like the basic signal levels are still to low even for B20.

What do you get when testing with your smartphone? If you get a decent speed and good signal levels with your phone check what mast it’s connected to by the Cell-ID and compare it with the device to check if its pointing to the same base station antenna.


About 2200 meters is still pretty close and no problem if you can manage to get a decent line-of-sight, that in this case is probably more important than the one which is closest.

What tower did your smartphone pick?

7

Thanks again.
From the living room two floors down it selects the same tower and cell as the mikrotik, at band 3, with similar poor performance Up/down.
I will do some LOS checks ( https://www.solwise.co.uk/wireless-elevationtool.html ) for the other to towers and see what they look like.
Then I will go up and move the Mikrotik to the “most promising one” and se what happens.
I have only tested it from the lower floors, so I guess moving up a few meters could be just enough to catch a sweet spot.

8

Sounds good, feel free to come back and tell me how it went. Have a good one!

9

OK, went up to the loft and moved antenna to the other end of the house, pointing at a bearing of 357 degrees to the tower - distance 2.2km / elevation diff 14m.
At first it locked at b3@10Mhz as primary band and b3@20Mhz as CA, but after a speedtest of 62/43Mbps DL/UL with 42 ms ping it had switched the primary and CA - which makes sence performance-wise for the upload speed.
Here are some output:

[admin@MikroTik] > /interface lte info lte1 once 
           pin-status: ok
  registration-status: registered
        functionality: full
         manufacturer: "MikroTik"
                model: "R11e-LTE6"
             revision: R11e-LTE6_V026
     current-operator: 24201
                  lac: 31501
       current-cellid: 19127816
               enb-id: 74718
            sector-id: 8
           phy-cellid: 16
    access-technology: LTE (CA2)
       session-uptime: 4m22s
         primary-band: B3@10Mhz earfcn: 1306 phy-cellid: 16
              ca-band: B3@20Mhz earfcn: 1450 phy-cellid: 373
                 rssi: -60dBm
                 rsrp: -85dBm
                 rsrq: -7.5dB
                 sinr: 16dB
[admin@MikroTik] > /interface lte cell-monitor lte1                        
PHY-CELLID BAND                                                          PSC EARFCN                                                                  RSRP          RSRQ          RSSI         SINR
        16 B3                                                                1306                                                                  -95dBm          -6dB
        17 B3                                                                1306                                                                 -110dBm       -19.5dB
        96 B3                                                                1450                                                                 -103dBm       -11.5dB
       348 B7                                                                3050                                                                 -124dBm         -16dB
       350 B7                                                                3050                                                                 -124dBm         -16dB
       374 B3                                                                1450                                                                 -102dBm       -19.5dB


[admin@MikroTik] > /interface lte info lte1 once    
           pin-status: ok
  registration-status: registered
        functionality: full
         manufacturer: "MikroTik"
                model: "R11e-LTE6"
             revision: R11e-LTE6_V026
     current-operator: 24201
                  lac: 31501
       current-cellid: 19127812
               enb-id: 74718
            sector-id: 4
           phy-cellid: 373
    access-technology: LTE (CA2)
       session-uptime: 6m36s
         primary-band: B3@20Mhz earfcn: 1450 phy-cellid: 373
              ca-band: B3@10Mhz earfcn: 1306 phy-cellid: 16
                 rssi: -60dBm
                 rsrp: -89dBm
                 rsrq: -7.5dB
                 sinr: 16dB
[admin@MikroTik] >

There are no locks in place, except I only allow LTE. The unit was powered off during the move, so a fresh start..
Any comments?

10

Looks like you nailed it at the initial “tryout”! Signal levels are significantly better and the ul-speed of 43 Mbit is actually very good.

At that speed, you should be able to get a ping latency of about 20-30 ms. Run a traceroute and pick the first available address that pops up and run a new ping test. You can also try to ping the gateway address in the lte1 interface (cmd: ip dhcp-client print detail). This will enable you to ping an address on the internal distribution network that causes a minimum delay.

Since this was the first attempt with the new placement, I would be very pleased. With a little further tweaking and fine tuning the location of the device, you can probably get another 10-15 Mbit on the inbound. But if you want to achieve significant greater improvements in speed than that, you need to establish a clear LoS by placing the antenna outdoors and without any visible obstacles to the tower.

11

Larsa,
Yes, I’m quite happy with this. But I had done quite thorough preparations in finding the bearing to use.
I am calling it the night now, but will look into your suggestions tomorrow.
Might also try the tower to the nort-west, just for the fun of it…
Thanks,
Jens

12

Please read that information:
Simple watchdog: http://forum.mikrotik.com/t/sxt-lte-4g-cat6/134468/1
Advance watchdog: http://forum.mikrotik.com/t/tx-rx-fp-rx-dropped-pppoe-account/132656/1
LOG & Watch LTE parameters: http://forum.mikrotik.com/t/r11e-lte6-2ca-not-staying-connected/136004/22

13

Thanks SIB,
I have seen those posts, and will investigate further.
But link currently seems much more stable, with Primary-band B3@20Mhz and CA-band b3@10Mhz giving down/up-speeds of 65/40.
Will investigate Larsas suggestion on improving/monitoring ping speeds, and get back when ready.
Jens
Edit: I have PRTG monitoring running, so I have some kind of historical data to help me when/if performance degrades.

14

Strange things are going on :slight_smile:
I went up to turn the unit towards the tower in the northwest, just as a test to se what I would get.
So I turned unit to bearing 294degrees. (old bearing was 357degrees), and restarted the unit.
Then went down to check what was going on, how the signals would be.
And strangely enough it was still sitting at the tower/cell from yesterday.
I thought it might be because they were both withing the 60degree sector of the antenna, so I turned it further west to bearing approx 270degrees.
New reboot, but its still sitting comfortable on the same cell from the tower in the north:

[admin@MikroTik] > /interface lte info lte1 once 
           pin-status: ok
  registration-status: registered
        functionality: full
         manufacturer: "MikroTik"
                model: "R11e-LTE6"
             revision: R11e-LTE6_V026
     current-operator: 24201
                  lac: 31501
       current-cellid: 19127812
               enb-id: 74718
            sector-id: 4
           phy-cellid: 373
    access-technology: LTE (CA2)
       session-uptime: 13m26s
         primary-band: B3@20Mhz earfcn: 1450 phy-cellid: 373
              ca-band: B3@10Mhz earfcn: 1306 phy-cellid: 16
                 rssi: -65dBm
                 rsrp: -94dBm
                 rsrq: -6.5dB
                 sinr: 14dB

As you can see, the signals are still quite good, even with that angle.And so are down/up speeds.
I am puzzled at what is going on.
I have tried to find position of towers based on cellid/lac etc. but I don’t think the databases are updated.
Anyone have good source for locations? (In Norway we have something called www.finnsenderen.no , but it just shows location and owner, not the ID’s .)

I am suspecting that when I thought I connected to the tower in the north yesterday, I actually connected to the tower in northwest.
I will try to point antenna to lets say bearing 30 to see if it changes.
…

15

OK, with unit pointing at bearing 30degrees it connected to a different cell:

[admin@MikroTik] > /interface lte info lte1 once 
           pin-status: ok
  registration-status: registered
        functionality: full
         manufacturer: "MikroTik"
                model: "R11e-LTE6"
             revision: R11e-LTE6_V026
     current-operator: N Telenor
                  lac: 31501
       current-cellid: 19127816
               enb-id: 74718
            sector-id: 8
           phy-cellid: 16
    access-technology: LTE (CA2)
       session-uptime: 11m10s
         primary-band: B3@10Mhz earfcn: 1306 phy-cellid: 16
              ca-band: B3@20Mhz earfcn: 1450 phy-cellid: 373
                 rssi: -65dBm
                 rsrp: -93dBm
                 rsrq: -7.5dB
                 sinr: 24dB
                   ri: 2

It gives me 73Mbps down but only 9 down, with ping of 51ms.
So I try to lock on b3@20Mhz using

/interface lte at-chat lte1 input="AT*Cell=2,3,,1450,373"

This gives me:

[admin@MikroTik] > /interface lte info lte1 once 
           pin-status: ok
  registration-status: registered
        functionality: full
         manufacturer: "MikroTik"
                model: "R11e-LTE6"
             revision: R11e-LTE6_V026
     current-operator: 24201
                  lac: 31501
       current-cellid: 19127812
               enb-id: 74718
            sector-id: 4
           phy-cellid: 373
    access-technology: LTE (CA2)
       session-uptime: 1m34s
         primary-band: B3@20Mhz earfcn: 1450 phy-cellid: 373
              ca-band: B3@10Mhz earfcn: 1306 phy-cellid: 16
                 rssi: -62dBm
                 rsrp: -90dBm
                 rsrq: -7dB
                 sinr: 16dB

And Down/Up of 86/22 with 43ms ping…
Hmm…
Guess I need to think a little about this, what is going on… :slight_smile:
Edit: No that didn’t look right, its back on current-cellid: 19127812 instead of current-cellid: 19127816

16

Larsa,

Here we go:
I didn’t get your command ip dhcp-client print detail to give us what you asked for, instead I got:

admin@MikroTik] > ip dhcp-client print detail 
Flags: X - disabled, I - invalid, D - dynamic

But I did a traceroute in webfig - tools, and the first hop is 77.16.1.145.
Doing a ping to that gives me

25 of 25 packets received	0 % packet loss	Min: 32 ms	Avg: 38 ms	Max: 64 ms

I guess I can live with that, and consider mounting the antenna outside for improvement. That side of my house is much easier to get to using a lift.

To let the mind wander a little:
As i understand it, the SXT LTE6 Kit has a 9dBi antenna gain, with a beamwidth of 60degree.
There is a new unit announced - the LHGG LTE6 kit - sporting a 17dBi antenna gain with a beamwidth of 25degree.
I am not very familiar with signal-theory, so bear over with me…
If I were to get this new LHGG LTE6 unit, what improvement should I be expecting compared to my current unit?
Or does the improved antenna gain just come into play over longer distances and weaker signals?
It seems from the antenna gain patterns in the brochure that the new unit has better gain at both the two frequencies used here (800Mhz and 1800Mhz):

SXT LTE6:       1.5dBi@800Mhz and  7.4dBi@1800Mhz
LHGG LTE6:      4.8dBi@800Mhz and 15.2dBi@1800Mhz

And as for my test to the northwest today: Maybe that tower does not have sector covering me?

17

One of the tools I have used to get the bearings can be found here:
https://setcompass.com/
Might be useful for others as well…

18

The difference in gain is what you get regardless the distance to cell tower. If you’re getting RSRP of -93dBm now, you’d get same cell at RSRP of around -85dBm. What changed antenna pattern does to interference depends where that interference comes from … if it’s from roughly direction towards cell tower, then RSRQ (or SINR, both measure ratio between signal and interference+noise) will remain the same. If, OTOH, interference source is in another direction, then using higher-gain antenna will improve RSRQ (and SINR).


Could be. Cell towers usually have high-gain antennae mounted and if none of them are directed in your direction, you won’t receive signal from that cell tower.

19

Thanks, mkx.

And this is probably near to impossible to answer, but I have to ask:
How could the increase in RSRP from -93dBm to -85dBm in the B3 band (1800Mhz) translate into response time (ping) and down/up speeds, roughly ?

20

Ping time likely won’t change (or not much). Change in UL/DL speeds will depend mainly on change in RSRQ/SINR. It will also depend on how MNO has QoS profiles set on cell tower. Ideally you could see double throughput, realistically 20-30% better, in (unlikely) worst case there won’t be any change.