A signal of 100MHz with harmonics is found at the RX input. See Spectrum Analyser screen grab when RX is connected to it.
RX connected to Spectrum Analyser Input
TX with 30dB load connected to spectrum analyser (not used)
Also test fail.
[ TEST STARTED ]
->Start time: Tue Mar 19 23:38:30 2019
->Device: LimeSDR Mini, media=USB 3, module=FT601, serial=1D424C3C64FD34, index=0
Serial Number: 1D424C3C64FD34
[ Clock Network Test ]
->REF clock test
Test results: 7380; 20577; 33774 - PASSED
->VCTCXO test
Results : 6711012 (min); 6711169 (max) - PASSED
->Clock Network Test PASSED
[ FPGA EEPROM Test ]
->Read EEPROM
data: 18 07 26 18 07 26 2
->FPGA EEPROM Test PASSED
[ LMS7002M Test ]
->Perform Registers Test
->External Reset line test
Reg 0x20: Write value 0xFFFD, Read value 0xFFFD
Reg 0x20: value after reset 0x0FFFF
->LMS7002M Test PASSED
[ RF Loopback Test ]
->Configure LMS
->Run Tests (TX_2 -> LNA_W):
->On board loopback test:
Test 1:(SXR=1000.0MHz, SXT=1005.0MHz, TXPAD=8): Result:(-46.8 dBFS, 5.00 MHz) - FAILED
->Configure LMS
->Run Tests (TX_1 -> LNA_H):
->On board loopback test:
Test 1:(SXR=2100.0MHz, SXT=2105.0MHz, TXPAD=8): Result:(-46.5 dBFS, 5.00 MHz) - FAILED
->RF Loopback Test FAILED
=> Board tests FAILED <=
Elapsed time: 4.90 seconds
Lime Suite GUI allows me to tune output signal and this does not interfere with RX.
The reception works, I can receive FM broadcast station as they are strong.
I try with a homemade probe to get signal at the RX stage but difficult as the FM signal is all over.
It clearly indicates that there is an issue with RF part. It considered to be OK down to ~22dBFS, but -46dBFS clearly indicates an issue. Check matching network components, maybe some of them are damaged.
I looked at the board RF part on binocular magnifier with no specific finding.
Looking at the schematic the Sky13411 IC3 IC4 and VT3 RF MOSFET are involved on the Loopback RF part if I am not wrong.
Where in Lime Suite GUI I can control RFSW TX and RX level for both IC3 and IC4 and as well for TX LB SH to do a try?
I connected the Lime RX to another RX SDR, see the result below:
RX SDR nothing connected
I can not answer this question. Every component in the chain, including LMS7002M may be affected.
Contact Crowd Supply for more details, please.
Connect to the board with LimeSuiteGUI, then go to menu item Modules → Board controls. Here you will find “RX RF port parg” and “TX RF port path” , “Loopback” controls.
