MC7455 Won't Connect to Network B41

[marcusa]

I have a ZBT-WG3526 running the latest R00ter (GoldenOrb_ Build 2017-12-15) and an MC7455.

I programmed in all the Sprint bands (and an option with all 3) as AT commands. But, when I force it to lock on B41, the Internet drops. When I check it's not on the Sprint network (see attachment). After a while like that all the info disappears (and yes, I am restarting the card after forcing the band). I even took the modem outside for better signal (67%) just in case that was it.

B41 works fine on my Sprint Note 5. Picking option 0D (all Sprint bands) fixes the issue on the card.

I reset the Sierra card to factory defaults and went at it from scratch to no avail.

Anyone have any ideas?

[JimHelms]

That really does not give us much to go by. Run the commands:

Code: Select all

at!entercnd="A710"
at!gstatus?

And post THESE results.

[marcusa]

When set to use any Sprint band:

Code: Select all

at!gstatus?
!GSTATUS: 
Current Time:  145		Temperature: 47
Reset Counter: 7		Mode:        ONLINE         
System mode:   LTE        	PS state:    Attached     
LTE band:      B25    		LTE bw:      5 MHz   
LTE Rx chan:   8415		LTE Tx chan: 26415
LTE CA state:  NOT ASSIGNED
EMM state:     Registered     	Normal Service 
RRC state:     RRC Connected  
IMS reg state: No Srv  		

PCC RxM RSSI:  -73		RSRP (dBm):  -95
PCC RxD RSSI:  -72		RSRP (dBm):  -92
Tx Power:      0		TAC:         2410 (9232)
RSRQ (dB):     -7.9		Cell ID:     0483540B (75715595)
SINR (dB):     13.8


OK

Immediately after locking B41:

Code: Select all

at!gstatus?
!GSTATUS: 
Current Time:  253		Temperature: 48
Reset Counter: 7		Mode:        ONLINE         
System mode:   LTE        	PS state:    Not attached 
LTE band:      No band		LTE bw:      1.4 MHz 
LTE Rx chan:   0		LTE Tx chan: 4294967295
LTE CA state:  NOT ASSIGNED
EMM state:     Deregistered   	Attach Needed  
RRC state:     RRC Idle       
IMS reg state: No Srv  		

PCC RxM RSSI:  0		RSRP (dBm):  0
PCC RxD RSSI:  0		RSRP (dBm):  0
Tx Power:      0		TAC:         FFFF (65535)
RSRQ (dB):     0.0		Cell ID:     FFFFFFFF (4294967295)
SINR (dB):     0


OK

About a minute after locking B41 it said no modem and then the modem showed up again (Modem present/Not connected) with this:

Code: Select all

at!gstatus?
!GSTATUS: 
Current Time:  418		Temperature: 47
Reset Counter: 7		Mode:        ONLINE         
System mode:   LTE        	PS state:    Not attached 
LTE band:      B41    		LTE bw:      20 MHz  
LTE Rx chan:   40978		LTE Tx chan: 4294967295
LTE CA state:  NOT ASSIGNED
EMM state:     Deregistered   	Attach Needed  
RRC state:     RRC Idle       
IMS reg state: No Srv  		

PCC RxM RSSI:  -93		RSRP (dBm):  -130
PCC RxD RSSI:  -83		RSRP (dBm):  -114
Tx Power:      0		TAC:         2410 (9232)
RSRQ (dB):     -11.7		Cell ID:     0497A432 (77046834)
SINR (dB):      4.2


OK

What's odd is immediately after connecting the other screen will show as I had in my previous attachment (w/signal strength) but after a minute none of the fields there are populated.

[JimHelms]

Notice the Cell ID when connected to Band 25 and compare it to the Cell ID when connecting to Band41. It is possible that these are two different towers, and that the Band25 tower does not have Band41--and it is trying to connect to another tower to receive Band41 whose signals are not adequate to stay connected.

Will it stay connected to Band25?

[marcusa]

It works great on B25 - just a little slow during congested times (20Mbps normally which is good, but will drop to 12 and sometimes lower during busy times).

I took the unit outside just to see if it helped. My phone was on B41 with a strong signal just fine, inside and outside. I may take it down the street to see if it works (and get an external antenna if that's the case). Any website where I can plug in the Cell ID and get the tower address?

Also, I could've sworn I saw a guide on this website showing what's a good signal on different bands but I can't find it and all the search terms are too common to use. Does that exist somewhere you know of or did I dream it?

Thanks for all your help!

[JimHelms]

There are several sites you can check the Cell ID. A google search should find them.

The signal strength chart is included in this topic.

[JimHelms]

You may also want to install an app on your phone to see what networks are available. Might give either Network Cell Info Lite or Netmonitor a try.

[RussWestrem]

The signal is to low and will drop packets. Are you running connection manager? If so, dont. The connection manager will restart your connection when it shouldn't with signals that bad.

[crumps]

What AT commands are you running to lock the card to a certain band and prioritize bands?

[JimHelms]

What AT commands are you running to lock the card to a certain band and prioritize bands?

This TUTORIAL has a section on locking bands.