FlightAware Discussions

Enabling bias-t for RTL-SDR dongle on Raspberry Pi OS

Got an RTL-SDR dongle recently, and since their own pre-amp isn’t ever in stock, I decided to get the Uputronics preamp instead.

That claims it can be powered with Bias-T, and the RTL-SDR dongle can also supply Bias-T power, but so far most of the tutorials I’ve seen to enable Bias-T are for RPIs running only the PiAware image, but my RPi runs Raspberry Pi OS as I use it for other stuff as well.

How would I go about activating Bias-T for the dongle, and ensuring it survives reboots / power losses?

3 Likes

Thanks, I get this from dump1090-fa after installing the script:

 dump1090-fa.service - dump1090 ADS-B receiver (FlightAware customization)
   Loaded: loaded (/lib/systemd/system/dump1090-fa.service; enabled; vendor preset: enabled)
  Drop-In: /etc/systemd/system/dump1090-fa.service.d
           └─bias-t.conf
   Active: activating (auto-restart) (Result: exit-code) since Sun 2021-04-18 15:52:01 PKT; 23s ago
     Docs: https://flightaware.com/adsb/piaware/
  Process: 1054 ExecStartPre=/usr/local/share/adsb-wiki/biastee/rtl_biast/build/src/rtl_biast -b 1 (code=exited, status=0/SUCCESS)
  Process: 1059 ExecStart=/usr/share/dump1090-fa/start-dump1090-fa --write-json /run/dump1090-fa --quiet (code=exited, status=1/FAILURE)
  Process: 1065 ExecStopPost=/usr/local/share/adsb-wiki/biastee/rtl_biast/build/src/rtl_biast -b 0 (code=exited, status=0/SUCCESS)
 Main PID: 1059 (code=exited, status=1/FAILURE)

The actual log for dump1090-fa would be useful.

Debug commands · wiedehopf/adsb-wiki Wiki · GitHub

1 Like

Here:

Unrelated to the biastee.

Apr 18 15:57:28 MSRPI dump1090-fa[1300]: Error opening the listening port 30003 (Basestation TCP output): bind: Address already in use

Typically means you have another dump1090 or fr24feed listening on 30003.
This will tell you what it is:

 sudo netstat -tlpen | grep 30003
1 Like

You were right, it was fr24feed. Fixed it.

Thanks for the script, was super easy to install.