RTL-SDR V3 (Bias Tee active) + GNU radio

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DrCdiff
Posts: 4
Joined: Sat Jan 16, 2021 1:26 pm

RTL-SDR V3 (Bias Tee active) + GNU radio

Post by DrCdiff » Sat Jan 16, 2021 2:07 pm

Hi,
I got my new RTL-SDR V3 and would like to use it with GNU radio and my Raspberry Pi 4. Also I need the internal Bias Tee to be active.

As far as I know I need 3 software components:
GNU radio
RTL-SDR source block
RTL-SDR-Blog driver

I had GNU radio + Source Blocks (gr-osmosdr) and + Driver (git://git.osmocom.org/rtl-sdr.git) with a RTL2832u running.
I tried to unistall the driver (sudo make uninstall in the folder) and install the speacial driver as described here: https://www.rtl-sdr.com/rtl-sdr-blog-v- ... ser-guide/

I can switch the Bias Tee on (./rtl_biast -b 1) and off (./rtl_biast -b 0) as described in the guide, but when I start a GNU radio program the Bias Tee gets deactivated.

https://github.com/rtlsdrblog/rtl-sdr-blog says I have to:

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sudo apt purge librtlsdr*
sudo rm -rvf /usr/lib/librtlsdr* /usr/include/rtl-sdr* /usr/local/lib/librtlsdr* /usr/local/include/rtl-sdr*
Unfortunatelly this uninstalls the RTL-SDR Source Block for GNU radio. When I reinstall gr-osmosdr the old behvior occurs.

I already tried "rtl_eeprom -i y" ("rtl_eeprom -b y" did not work. The program said that there is no "-b"). This activates the Bias Tee and I can't switch it off with "./rtl_biast -b 0" but it still gets deactivated with GNU radio.

I think there are 2 possible problems:
A: GNU radio activates the old driver and the RTL-SDR-Blog driver is not active anymore
B: GNU radio deactivates the Bias Tee

To solve A, I could start with a fresh Raspbian, install the RTL-SDR-Blog driver (https://github.com/rtlsdrblog/rtl-sdr-blog), GNU radio and then gr-osmosdr.
I have no idea how to solve B.

Any suggestions?

DrCdiff
Posts: 4
Joined: Sat Jan 16, 2021 1:26 pm

Re: RTL-SDR V3 (Bias Tee active) + GNU radio

Post by DrCdiff » Sat Jan 16, 2021 8:56 pm

I started again with a fresh Raspbian

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sudo apt-get update
sudo apt-get upgrade
sudo apt-get install gnuradio
Then the driver:

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sudo apt update
sudo apt install libusb-1.0-0-dev git cmake
git clone git://github.com/rtlsdrblog/rtl-sdr-blog.git
cd rtl-sdr-blog/
mkdir build
cd build
cmake ../ -DINSTALL_UDEV_RULES=ON
make
sudo make install
sudo cp ../rtl-sdr.rules /etc/udev/rules.d/
sudo ldconfig

echo 'blacklist dvb_usb_rtl28xxu' | sudo tee --append /etc/modprobe.d/blacklist-dvb_usb_rtl28xxu.conf
Additional stuff for GNU radio:

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sudo apt-get install xterm
sudo apt-get install gr-osmosdr
I can activate the Bias Tee with "./rtl_biast -b 1" and "rtl_eeprom -b y" (now including "-b"!) works, but whenever GNU Radio starts, the Bias Tee is switched off. Apart from the Bias Tee GNU Radio works fine.

DrCdiff
Posts: 4
Joined: Sat Jan 16, 2021 1:26 pm

Re: RTL-SDR V3 (Bias Tee active) + GNU radio

Post by DrCdiff » Sat Jan 16, 2021 9:11 pm

When I run "rtl_biast -b 1" I get the following error:

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 rtl_biast: symbol lookup error: rtl_biast: undefined symbol: rtlsdr_set_gpio
Does gr-osmosdr also include the driver? It looks for me like I have two competing drivers ...


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