So we took one of the devices with consistently (seems capped) upload speeds of 400kbps to a site with a working device. Connecting it to the same antenna that was giving 20M/20M to another device, the "bad" device is getting 400kbps.
So after a lot of comparison between the 2 we found that the firmware and HW revisions are different. Here's what they look like:
Working Device
Model EM7455
Firmware SWI9X30C_02.33.03.00
HW Revision EM7455
NON-Working (slow) Device
Model EM7455
Firmware SWI9X30C_02.33.03.00 r8209 CARMD-EV-FRMWR2 2019/08/28 20:59:30
HW Revision “1.0”
What is the extra "r8209 CARMD-EV-FRMWR2 2019/08/28 20:59:30"?? I tried re-flashing again with the latest image from Sierra's site and that extra stuff remains.
Could these be some kind of early hardware revision?
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Here I go again. I swear these devices are out to kill me or cause me to go crazy. I have spent so many hours with these modems with absolutely no clear path to victory. I simply don't understand it.
Here's the situation -- Brand new, fresh install of Ubuntu 20.04 from ISO in our office and the modem works fine. 30M down, 30Mish up. Consistent. Steady. Great. No issues at all.
Take it to the site, about 30-35 miles away. MAJOR urban area, city, lots of sites. 30M down, 0.4M up. Steady, consistent, never moves. I can't get any decent upload speeds. Its the same SIM, same hardware, same EVERYTHING that was working 30M/30M just 45 minutes earlier, but when it gets to the new location the upload speeds are non-existent.
So, I check AT!GSTATUS and see that my SINR is low, 6-8. I create some band plans based on cellmapper info since I know that I have a tower with Bands 2, 5, 13, and 66 nearby. B2 is no good, SINR is typically around 5. So I change my band plan to 5 and 13. AT!RESET and reboot.
Now I'm on B5 and everything (to me) looks great:
Code: Select all
!GSTATUS:
Current Time: 848 Temperature: 37
Reset Counter: 3 Mode: ONLINE
System mode: LTE PS state: Attached
LTE band: B5 LTE bw: 10 MHz
LTE Rx chan: 2560 LTE Tx chan: 20560
LTE CA state: NOT ASSIGNED
EMM state: Registered Normal Service
RRC state: RRC Connected
IMS reg state: Full Srv IMS mode: Normal
PCC RxM RSSI: -62 RSRP (dBm): -86
PCC RxD RSSI: -63 RSRP (dBm): -86
Tx Power: -15 TAC: 6701 (26369)
RSRQ (dB): -11.3 Cell ID: 018C2625 (25962021)
SINR (dB): 17.6
Code: Select all
Hosted by Sprint (Springfield, MA) [22.29 km]: 52.641 ms
Testing download speed................................................................................
Download: 31.60 Mbit/s
Testing upload speed......................................................................................................
Upload: 0.40 Mbit/s
Modem gods, please help!
