Receiving and transmitting at 1MHz

Projects LimeSDR
3

Hi Marty,

Thanks for your reply - I’ve tried transmitting using a simple GNURadio flow (grc file here).

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When transmitting a single tone at various frequencies, these are the outputs (as measured by my DSA815):

  • 50MHz: 3.2dBm
  • 20MHz: -42dBm (!)
  • 10MHz: -68dBm
  • 5MHz: -81dBm
  • 2MHz: -94dBm
  • 1MHz: -102dBm, I can just about resolve this if I crank the spectrum analyser RBW all the way down.

Now these values are much much smaller than what you measured at 1.825MHz (-8.77dBm compared to -94dBm). I ran LimeQuickTest but no problems were found, so hopefully there’s no hardware issue. Here’s the output:

[ TESTING STARTED ]
->Start time: Fri Nov  8 13:46:03 2019

->Device: LimeSDR-USB, media=USB 2.0, module=FX3, addr=1d50:6108, serial=XXXXXXXXXXXXXXXX
Warning: USB3 not available
  Serial Number: XXXXXXXXXXXXXXXX

[ Clock Network Test ]
->FX3 GPIF clock test
  Test results: 25316; 29072; 32828 - PASSED
->Si5351C test
  CLK0: 17555 / 17554 - PASSED
  CLK1: 17555 / 17554 - PASSED
  CLK2: 17555 / 17554 - PASSED
  CLK3: 17555 / 17554 - PASSED
  CLK4: 17555 / 17554 - PASSED
  CLK5: 17555 / 17554 - PASSED
  CLK6: 17555 / 17554 - PASSED
->ADF4002 Test
  Result: 10 - PASSED
->VCTCXO test
  Results : 5112944 (min); 5113079 (max) - PASSED
->Clock Network Test PASSED

[ FPGA EEPROM Test ]
->Read EEPROM
->Read data: 12 08 06 12 08 06 02
->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 ]
Note: The test should be run without anything connected to RF ports
->Configure LMS
->Run Tests (TX_2-> LNA_L):
  CH0 (SXR=800.0MHz, SXT=805.0MHz): Result:(-12.2 dBFS, 5.00 MHz) - PASSED
  CH1 (SXR=800.0MHz, SXT=805.0MHz): Result:(-14.5 dBFS, 5.00 MHz) - PASSED
->Run Tests (TX_1 -> LNA_W):
  CH0 (SXR=1800.0MHz, SXT=1805.0MHz): Result:(-11.9 dBFS, 5.00 MHz) - PASSED
  CH1 (SXR=1800.0MHz, SXT=1805.0MHz): Result:(-16.0 dBFS, 5.00 MHz) - PASSED
->Run Tests (TX_2-> LNA_H):
  CH0 (SXR=2500.0MHz, SXT=2505.0MHz): Result:(-15.7 dBFS, 5.00 MHz) - PASSED
  CH1 (SXR=2500.0MHz, SXT=2505.0MHz): Result:(-13.0 dBFS, 5.00 MHz) - PASSED
->RF Loopback Test PASSED

=> Board tests PASSED <=

Elapsed time: 2.73 seconds

My hardware version is v1.4s. Are you using a different version perhaps? Can any of the Lime team shed light on this please?

Thanks