case about nRF9160 AT cmd AT%XRFTEST=1,1,28,7480,17,0,3,12,0,0,0,0,0 failed

[peter.min]

Hi,

Why does setting this frequency fail to transmit

Thank you for all your assistance.
Kind regards,
Peter.Min

[dejans]

Hi,

Could you provide more information on what you want to test? 

Could you describe the problem in detail?

Could you provide all commands so that I could try to reproduce the issue?

Best regards,
Dejan

[peter.min]

Hi dejans,

1. Its purpose is to test the RF performance of frequency point 748MHz.

2. I tested the  Band 28.

Its start 703MHz tests ok

Its end 748Mhz test failed.(Why did the test fail at this point)

3. The AT command above is all the instructions

Thank you for all your assistance.
Kind regards,
Peter.Min

[dejans]

Hi,

Looking at your screenshot, there seem to be some command or commands entered before AT%XFACTORYRESET=0. Could you provide all AT commands that you entered from the moment you opened LTE Link Monitor?

Which application sample did you flash to your board?

Best regards,
Dejan

[peter.min]

Hi,

1.The first at command is

AT+CFUN?

+CFUN: 0

OK

The AT command above is all the instructions

2.The application is serial_lte_modem.

Thank you for all your assistance.
Kind regards,
Peter.Min

[dejans]

Hi,

I have reproduced the error. I have made an internal inquiry. I'll get back to you when I get new information.

Best regards,
Dejan

[dejans]

Hi,

The error we both observed is not an actual error, but it comes up as an error when frequency values are not properly chosen. Chapter 5.7.3 of the ETSI TS 136 101 V14.22.0 Rel 14 specifies the formula for calculating the UL frequency. For example, for band 1 this would give value of 1979.9 MHz and for band 28 the value would be 747.9 MHz. Therefore, the command that you used for band 28 should not be done with value 7480, but with the value 7479 for the UL upper bound. I have tested this myself and it worked on my side. Please note that it is up to the user to correctly make limitations for the transmission frequency. 

Best regards,
Dejan

[peter.min]

Hi dejans,

Very clear answer

Thank you for all your assistance.
Kind regards,
Peter.Min