Bladerf gains
Posted: Fri Apr 27, 2018 9:17 am
In my latest project of an RTL SDR receiver, I've replaced my old NooElec usb key, with a brand new BladeRF board. I've started using the gnuradio-companion examples found in the bladerf folders.
The first think I noticed is that the bladerf is much less sensitive than the NooElec key receiver. Also increasing all the available gains I don't succeed in receiving the same signals I do with the old NooElec.
Looking into the osmocom gnuradio-companion block I see there are three possible gains, the RF gain, the IF gain and the BB gain. The osmocom source uses just only the RF and the BB ones. But also setting them at the maximum value, RF at 6dB and the BB gain at 60dB I still don't succeed in reaching the same sensitivity.
Some infos ont he system:
the command bladeRF-cli info returns
Serial #: 5bd6b19656b61627c92d158e21e14a13
VCTCXO DAC calibration: 0x9398
FPGA size: 115 KLE
FPGA loaded: yes
USB bus: 2
USB address: 2
USB speed: SuperSpeed
Backend: libusb
Instance: 0
the version is
bladeRF-cli version: 1.5.1-2017.12-rc1-1-ppaartful
libbladeRF version: 1.9.0-2017.12-rc1-1-ppaartful
Firmware version: 2.0.0
FPGA version: 0.6.0
The system runs on a gnuradio:amd64/artful 3.7.10.1-2ubuntu2 uptodate.
It is also a bit confusing the relationship between the gain of the osmocom block, and the bladerf gains LNA, RXVGA1 and RXVGA2. Some explanation would be helpful.
In the next step I will try to use an external LNA and filter, to see if I can compensate the low sensitivity.
Best regards
Claudio
The first think I noticed is that the bladerf is much less sensitive than the NooElec key receiver. Also increasing all the available gains I don't succeed in receiving the same signals I do with the old NooElec.
Looking into the osmocom gnuradio-companion block I see there are three possible gains, the RF gain, the IF gain and the BB gain. The osmocom source uses just only the RF and the BB ones. But also setting them at the maximum value, RF at 6dB and the BB gain at 60dB I still don't succeed in reaching the same sensitivity.
Some infos ont he system:
the command bladeRF-cli info returns
Serial #: 5bd6b19656b61627c92d158e21e14a13
VCTCXO DAC calibration: 0x9398
FPGA size: 115 KLE
FPGA loaded: yes
USB bus: 2
USB address: 2
USB speed: SuperSpeed
Backend: libusb
Instance: 0
the version is
bladeRF-cli version: 1.5.1-2017.12-rc1-1-ppaartful
libbladeRF version: 1.9.0-2017.12-rc1-1-ppaartful
Firmware version: 2.0.0
FPGA version: 0.6.0
The system runs on a gnuradio:amd64/artful 3.7.10.1-2ubuntu2 uptodate.
It is also a bit confusing the relationship between the gain of the osmocom block, and the bladerf gains LNA, RXVGA1 and RXVGA2. Some explanation would be helpful.
In the next step I will try to use an external LNA and filter, to see if I can compensate the low sensitivity.
Best regards
Claudio