Extremely slow LTE/5G on GL-X3000

Technical Support for Routers 4G LTE, 5G NR, USB modems
1

I have a Vodafone Red+ (germany) data SIM. Connection registers fine and usually shows decent 5G signal, as below:

image
image643×780 24.9 KB

However, the connection is essentially unusable as the data rate is generally <1Kbps, so I am e.g. able to load google.com but it takes several minutes. The strange thing is that it has actually worked fine on some occasions, and I have recorded speed tests with >300Mbps downloads. Phone on the same plan (Red+ is a data-only add-on card that shares my quota) shows good speeds.

I have upgraded firmware to RM520NGLAAR03A04M4G_01.202.01.202, set mbn to ROW_Commercial, no effect. APN is web.vodafone.de. SIM shows active in the vodafone website.

A lot of posts suggest looking up 5G bands on the phone and locking/masking to those, but after a bit of googling it appears that it's not actually possible to view 5G bands on android 15/Pixel 9 Pro without root? I tried several apps and none of them seem to show the band information.

What steps should I take to diagnose this situation?

2

factory reset router as well, no effect with that either

3

Try downloading the Android APP Cellular-Z on phone to see if it can check the bands?

If above APP does not work, you can try to lock the scanned bands related to the current SIM operator.

4

I was able to see my LTE bands (B1 and B7) with Cellular Z but not the 5G NSA bands. Setting them to what the provider seems to use (n1, n3, n28, n78) didn't change anything.

5

Hello @parkan

Please check antennas and make sure all antennas are connected properly.

In addition, help to check the following AT command outputs when router internet is normal and when speed goes down, so as to compare:

AT+QREJINFO?
AT+CGDCONT?
AT+CGCONTRDP

If convenient, when speed issue occurs, log in to ssh terminal and run command, and then share pcap file with us for further analysis :
tcpdump -i rmnet_mhi0 > modem.pcap