Frequent modem disconnects MC7455/WG3526

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Vegas
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Frequent modem disconnects MC7455/WG3526

Post by Vegas » Fri Jan 18, 2019 6:42 pm

The modem drops connection frequently, seems to correspond with a new or returning device accessing wifi. Other wifi devices can still communicate to the router, but no internet service. I setup connection monitoring with modem reconnect which brings it back up very quickly.

I've already reset and reconfigured the modem to MBIM and added the Sprint OTA. No change. Using Calyx Sprint SIM.

Any ideas?
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sysandconnectionlogWG.txt
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JimHelms
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Re: Frequent modem disconnects MC7455/WG3526

Post by JimHelms » Sat Jan 19, 2019 9:59 am

What does your signal stats look like while connected. It is possible that the signals are less than optimal, and it is connecting on Band 41 at 2500HMz and the 2.4GHz (2400MHz) may be interfering and/or interrupting the quality of signals being received by the modem.

Also, try disabling Connection Monitor.

While it is connected, run the following command and post the results:

Code: Select all

AT!GSTATUS?

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Re: Frequent modem disconnects MC7455/WG3526

Post by Vegas » Sat Jan 19, 2019 1:36 pm

Without connection monitoring, it does the same thing but requires intervention to reconnect... resetting the router or modem.

Code: Select all

AT!GSTATUS?
!GSTATUS: 
Current Time:  30790		Temperature: 50
Reset Counter: 12		Mode:        ONLINE         
System mode:   LTE        	PS state:    Attached     
LTE band:      B41    		LTE bw:      20 MHz  
LTE Rx chan:   41292		LTE Tx chan: 41292
LTE CA state:  ACTIVE      		LTE Scell band:B41    
LTE Scell bw:20 MHz  		LTE Scell chan:41490
EMM state:     Registered     	Normal Service 
RRC state:     RRC Connected  
IMS reg state: No Srv  		

PCC RxM RSSI:  -62		RSRP (dBm):  -92
PCC RxD RSSI:  -71		RSRP (dBm):  -97
SCC RxM RSSI:  -68		RSRP (dBm):  -98
SCC RxD RSSI:  -66		RSRP (dBm):  -92
Tx Power:      5		TAC:         012B (299)
RSRQ (dB):     -6.5		Cell ID:     0034A43A (3449914)
SINR (dB):     25.6


OK

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Re: Frequent modem disconnects MC7455/WG3526

Post by JimHelms » Sat Jan 19, 2019 3:14 pm

Your antenna stats are usable.

Your issue could be related to the MTU value being too large for the tower you are using. This seems to affect some and not others.

This are recent discussions on the GoldenOrb Forum concerning this type of Sprint connection issues. Start on the bottom page and read forward.

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Re: Frequent modem disconnects MC7455/WG3526

Post by Vegas » Mon Jan 21, 2019 9:52 am

I changed to n.ispsn and set the MTU value to the one suggested in the forum... still disconnecting. I'll see if disabling the wifi and setting up another router as an AP will be smoother.

It's definitely workable... it reconnects so quickly it doesn't even stop video streaming. Every once in awhile I'll notice a website take too long to load and I know it's resetting, and see it in the logs, but I can live with that. I just wish I could pin point the cause.

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Re: Frequent modem disconnects MC7455/WG3526

Post by JimHelms » Mon Jan 21, 2019 10:35 am

What did you finally use for the MTU value? You might also try 1428.

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Re: Frequent modem disconnects MC7455/WG3526

Post by Vegas » Mon Jan 21, 2019 3:27 pm

1484. I'll try 1428

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Re: Frequent modem disconnects MC7455/WG3526

Post by JamesReinhold » Wed Sep 25, 2019 8:49 pm

Jumping in to add another suggestion on this thread. I've built 2 MC7455/WG3526 setups and one has had very good performance. The other was good for a while and then also started having what appeared to be frequent disconnects, but where actually reboots. This was happening anytime the router/modem was being used (traffic) or multiple devices connecting. I isolated the router and modem card - which worked fine independently. Going off a hunch I swapped power adapters between the two WG3526's and right away noticed they were different.

This is the power adapter for the WG3526 that was rebooting under traffic load:
20190925_065229.jpg
And this is the power adapter for the WG3526 that is working fine:
20190925_165707.jpg
Now - not sure why these are different, but both are what came with the WG3526 and they have quite different outputs.

So may want to check power supply when running into reboot type issues.

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Re: Frequent modem disconnects MC7455/WG3526

Post by BillA » Fri Jan 03, 2020 1:15 am

JamesReinhold wrote:
Wed Sep 25, 2019 8:49 pm
Jumping in to add another suggestion on this thread. I've built 2 MC7455/WG3526 setups and one has had very good performance. The other was good for a while and then also started having what appeared to be frequent disconnects, but where actually reboots. This was happening anytime the router/modem was being used (traffic) or multiple devices connecting. I isolated the router and modem card - which worked fine independently. Going off a hunch I swapped power adapters between the two WG3526's and right away noticed they were different.

Now - not sure why these are different, but both are what came with the WG3526 and they have quite different outputs.

So may want to check power supply when running into reboot type issues.

Well, no wonder, the top adapter is a 0.75Amp at 8Volts (which equals to only 0.50Amp at 12Volts), while the bottom one is much beefier 2.5Amp at 12Volts, in other words the top one is really low, thus the frequent disconnects. By the way, you can't really trust the labels either, I've come across labels showing 2Amp at 12Volts which turned out more like 1Amp even under a light load. I've learned over decades of troubleshooting electronics, that most issues turn out to be simpler than thought, yet we keep digging in all the wrong places.

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Re: Frequent modem disconnects MC7455/WG3526

Post by ruralbee » Sun Jan 19, 2020 7:59 pm

I'm getting the exact same behavior on EM7565. I'm on Sprint as well with r.ispsn. I upgraded from the MC7455 to the EM7565 hoping to fix the connection drops. It goes faster but drops just as much, if not more, & is mainly noticeable under load. I have upgraded the USB cable, tried it with connection monitoring, without, varying the settings, etc... Not much improvement. MBIM or QMI doesn't seem to make much of a difference.

I'm using a Linksys WRT1900ACS with the USB enclosure w/ a 3A stock power supply. External omni antennas about 4 miles from Sprint, nearly LOS.

I'll let you know if I figure out a solution. It feels like it is a USB issue but I can't confirm that. I had narrowed the system & kernel log down but I have no idea what it means.

my logs are attached for reference & comparison

Code: Select all

AT!GSTATUS?
!GSTATUS: 
Current Time:  2240		Temperature: 35
Reset Counter: 51		Mode:        ONLINE         
System mode:   LTE        	PS state:    Attached     
LTE band:      B41    		LTE bw:      20 MHz  
LTE Rx chan:   41094		LTE Tx chan: 41094
LTE SSC1 state:INACTIVE    	LTE SSC1 band: B40    
LTE SSC1 bw  : 20 MHz  		LTE SSC1 chan: 41292
LTE SSC2 state:INACTIVE    	LTE SSC2 band: B40    
LTE SSC2 bw  : 20 MHz  		LTE SSC2 chan: 41490
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:  -63		PCC RxM RSRP:  -96
PCC RxD RSSI:  -63		PCC RxD RSRP:  -91
SCC1 RxM RSSI: -76		SCC1 RxM RSRP: -97
SCC1 RxD RSSI: -72		SCC1 RxD RSRP: -89
SCC2 RxM RSSI: -82		SCC2 RxM RSRP: -99
SCC2 RxD RSSI: -75		SCC2 RxD RSRP: -91
Tx Power:      --		TAC:         1e20 (7712)
RSRQ (dB):     -10.0		Cell ID:     03d55f32 (64315186)
SINR (dB):      5.4


OK
Attachments
systemlog.txt
(12.97 KiB) Downloaded 67 times
kernel_log.txt
(1.34 KiB) Downloaded 52 times
AT!GSTATUS.txt
(991 Bytes) Downloaded 58 times

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