Wireless Joint

Hello Everyone,

Really appreciate the experts helping out on this forum - I've learned a lot through reading many of the forum posts here.

I'm having an issue with my Sierra Wireless EM7511 modem working for a while (hours, days), then the internet either stops working or slows to a crawl. If I power cycle the router or reset the modem via AT command, I usually get internet back at a reasonable speed (2-4 Mb/s), though sometimes I'll still have minimal/no internet. I don't understand networking well enough to troubleshoot this issue, and would appreciate any help in what I should be checking or testing to see why it isn't working when it stops, so I can figure out how to fix it. A part of me thinks it might just be weak signal or tower congestion, but the fact that I can often do a reset and get good internet back makes me think there is something else going on.

My setup:
Sierra Wireless EM7511 with 01.11.00.00 generic firmware (SW release notes identify this as Release 14 that is carrier approved for Telstra, but at!IMPREF? returns "generic" under carrier. This FW is outdated - wonder if I should reflash to latest Verizon, or latest generic?)

ZBT-WG2536 router with WiFiX-NEXP1GO-GO2021-09-11-upgrade.bin firmware

Router and modem were purchased used. I did a clean install of the router firmware which seems to have fixed a DHCP lease issue I was having.

Cell network is Visible. I have not applied any "magic" to the IMEI. Antenna is currently set up in my living room, trying to get this stable before I put it up on the roof. Signal strength is OK but not great (if I understand it correctly...):

AT!GSTATUS?
!GSTATUS:
Current Time: 149 Temperature: 35
Reset Counter: 3 Mode: ONLINE
System mode: LTE PS state: Attached
LTE band: B4 LTE bw: 10 MHz
LTE Rx chan: 2100 LTE Tx chan: 20100
LTE SSC1 state:NOT ASSIGNED
LTE SSC2 state:NOT ASSIGNED
LTE SSC3 state:NOT ASSIGNED
LTE SSC4 state:NOT ASSIGNED
EMM state: Registered Normal Service
RRC state: RRC Connected
IMS reg state: No Srv
PCC RxM RSSI: -82 PCC RxM RSRP: -110
PCC RxD RSSI: -80 PCC RxD RSRP: -107
Tx Power: -- TAC: 0509 (1289)
RSRQ (dB): -11.1 Cell ID: xxxxxxxxxxxx
SINR (dB): 9.4
OK

While typing this up my internet went from decent after a restart to terrible (40 Kb/s) and stayed terrible through three different modem resets, but now is good again (3 Mb/s) after about 20 minutes of terrible. Comparing my signal strength numbers to what I posted above (which were taken when internet speed was terrible), everything is about the same except the SINR, which is now 2.6 dB, but bounces all over the place.

Hello,
With the antenna inside could just be having extreme signal changes. When the SINR is very bad your performance will be bad. For now would pay attention to that signal. Could you rig the antenna outside a window. Or maybe band lock to lower frequency bands that are easier to get connection too like bands 13 and 5. Now these bands are not fast or ideal but could see if you could get consistency with them.

Thank you for the response. I have tried other bands and found band 4 to be the most consistent. My antenna is at a large window aimed at the tower. There are a lot of trees in the way though, and the metal siding and soffits on my house could be causing interference?

I have not noticed a good correlation between SINR and performance - A moment ago the SINR was at 10.8 and I had no internet. I stepped away for 5 minutes and now the SINR is changing from 1.6-9.6 (changes significantly every 10 seconds when the debug info updates), and I have 1-3 Mb/s.

I have everything to get the router and antenna up on the roof - maybe that will solve the issue with a stronger signal, but still not sure why resetting the modem will often result in good speeds.

Guess you could take it in your car and go close to the tower and see what happens. Continues to ask crazy when close to it you know something else is up.