Changing NB-IoT Bands
Having Problems connecting your Dragino NB-IoT device? Changing Bands might be an option, here's how.
Problem
BC660K-GL supports multi bands:
B1/B2/B3/B4/B5/B8/B12/B13/B14/B17/B18/B19/B20/B25/B28/B66/B70/B85.
It will search one by one and try to attach, this will take a lot of time and even cause attach to fail and show Signal Strenght:99. User can lock the band to specify band for its operator to make this faster.
What happens is that the device starts at the first band, and probably in your country, the last one is used. Before the device can reach and try to attach using the needed band, it goes to sleep before it can connect, as the device connection routine has no option to search for the corresponding band. It always does this reconnect and cycle through all bands with every message sent. It will always fail.
Solution
The solution is to lock the bands to the ones used in your country, and here's how you can do it.
This method is valid for BG660 devices, which are the latest series of Dragino devices with BLE connectivity for accessing the firmware terminal and button on the casing.
Connect via BLE Terminal
Connect to your device using a BLE Terminal
Enter the password to be able to communicate with the firmware (the password usually is on a sticker on the device packaging)
Enter Band Commands
Issue the following AT commands:
AT+QENG=0 to check which band is actually in used.
AT+QBAND? // Check what is the current used frequency band
AT+QBAND=1,4 // Set to use 1 frequency band. Band4
Europe General AT+QBAND=2,8,20 // Set to use 2 frequency bands. Band 8 and Band 20
Using 1NCE?
Band 20 probably is all you need
Dragino Wiki
For all Bands: See: http://wiki.dragino.com/xwiki/bin/view/Main/NB-IoT%20Deployment%20%2C%20Bands%2C%20Operator%20list/
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