Hello,
I am using multiple Quectel RG500Q-EA modules with the **same firmware, and I’m observing something strange during WCDMA testing in South Korea.
There are two active WCDMA Band 1 cells in my area:1.
- 10737 (SK Telecom, UARFCN 10737, 2132.4 MHz)
- 10836 (KT, UARFCN 10836, 2149.8 MHz)
Observation:
- Most modules only detect 10836
ex )
at+qeng=“servingcell”
+QENG: “servingcell”,“LIMSRV”,“WCDMA”,450,08,4020,20A81A5,10836,180,42,-67,-3,-,-,-,-,-
OK
at+qeng=“neighbourcell”
+QENG: “neighbourcell”,“WCDMA”,10836,-59,348,-820,-225,2,-32768,-
+QENG: “neighbourcell”,“WCDMA”,10836,-59,217,-830,-240,2,-32768,-
+QENG: “neighbourcell”,“WCDMA”,10836,-59,12,-840,-250,2,-32768,-
OK
- Some modules only detect 10737
ex)
at+qeng=“servingcell”
+QENG: “servingcell”,“LIMSRV”,“WCDMA”,450,05,2241,4815500,10737,62,1,-74,-6,-,-,-,-,-
OK
at+qeng=“neighbourcell”
+QENG: “neighbourcell”,“WCDMA”,10737,-68,71,-750,-65,2,-13,-
+QENG: “neighbourcell”,“WCDMA”,10737,-68,2,-840,-160,2,-32,-
+QENG: “neighbourcell”,“WCDMA”,10737,-68,60,-850,-165,2,-34,-
- All modules use the same firmware, same AT commands, and same test location/antenna
What I’ve confirmed:
- No SIM is inserted (test is passive)
- LTE detection works fine for all bands
- WCDMA servingcell and neighbourcell behavior varies by module
My questions:
- What could cause this frequency-specific behavior across modules that are otherwise identical?
- Is it possible to select a specific WCDMA UARFCN ?
Additional Question:
- In WCDMA mode, does the module only report neighbor cells that are on the same frequency as the serving cell?
I noticed that when one UARFCN is used as the serving cell, only that frequency appears in the neighbor cell list. Is this expected behavior?
Any insights or suggestions would be greatly appreciated. Thank you!