Flightradar24
DVB-T
From the 1950s to the 2010s, television broadcasting was analogue and delivered via terrestrial transmitters, community antenna systems using coaxial cabling, or satellites. Terrestrial analogue TV in Europe used UHF channels 21–69, each 8 MHz wide, covering the 470–862 MHz range.
Higher frequencies allow wider bandwidth and smaller antennas but require higher transmitter power and provide shorter propagation distances. Under the "digital dividend", the ITU‑R WRC reallocated parts of the UHF band to mobile broadband. Digital terrestrial TV (DVB) uses the spectrum more efficiently by multiplexing multiple MPEG transport streams into one RF channel, allowing more services with higher picture quality within the same bandwidth.
DVB‑S is used for satellite, DVB‑C for cable networks, and DVB‑T for terrestrial broadcast. DVB‑T uses MPEG‑2 video compression, while DVB‑T2 uses the more aggressive MPEG‑4/H.264.
RTL‑SDR
Low‑cost USB tuner sticks equipped with an R820T/T2 tuner and an RTL2832U demodulator can receive DVB‑T and also function as software‑defined radios (RTL‑SDR). The tuner selects and down‑converts the RF channel, while the RTL2832U converts the signal to a digital baseband stream. Because the RTL2832U can output raw I/Q samples, signal demodulation can be performed entirely in software, allowing reception of a wide range of signals beyond DVB‑T.
Antenna
These receivers typically expose an antenna input using SMA (not RP‑SMA) or MMCX connector. Coaxial cable enables placement of the antenna away from the receiver with minimal loss. An active bias-tee antenna includes an amplifier to raise the signal level before the coaxial run. A balun (balanced‑to‑unbalanced transformer) is used to interface certain antennas and can also block unwanted DC on the feed line. 1090Mhz has a wave length of 27.0 cm. Use an omnidirectional antenna with a length proportional to the frequency, for instance a J-Pole antenna inside a PVC pipe.
https://www.steeman.org/ADSB/Antenna-Comparison-Tests
https://discussions.flightaware.com/t/new-antenna-10x-increase-not-even-outside-yet/17108
ADS‑B
Active radar transmits pulses and measures reflections from aircraft. By contrast, ADS-B is a passive surveillance system in which aircraft broadcast their own position, altitude, velocity, and other telemetry. ADS‑B transmissions use 1090 MHz Extended Squitter (Mode S). RTL‑SDR receivers can capture these broadcasts for aircraft tracking.
https://mode-s.org/1090mhz/content/quickstart.html
UAT on 978Mhz is newer, less common, not mandatory yet, requires additional processing power and probably a second DVB stick?
Raspberry Pi
A Raspberry Pi is a relatively cheap computer based on an ARM Cortex-A processor from Broadcom that can run Linux. A Raspberry Pi 3B+ or higher, has enough computing power to run SDR decoding. The raspberry pi does need a USB powersupply that delivers atleast 2.4Watt, otherwise it starts behaving unreliably.
sudo cat /sys/firmware/devicetree/base/model;echo Raspberry Pi 3 Model B Plus Rev 1.4
The RTL DVB-T USB Stack can be connected directly into the raspberry pi
rtl_test -t Found 1 device(s): 0: Realtek, RTL2838UHIDIR, SN: 00000001 Using device 0: Generic RTL2832U OEM
lsusb Bus 001 Device 005: ID 0bda:2838 Realtek Semiconductor Corp. RTL2838 DVB-T
USB on a raspberry pi can become unstable when C98 breaks, then usb devices will not be recognized anymore
The 5V power for an active antenna can be drawn from a 5V and GND pins. You can also use a GPIO pin, which allows you to enable or disable the antenna, but there is little benefit to this.
raspi-gpio set 24 op pn dh
Flightradar24
https://www.flightradar24.com/build-your-own
Flightradar24 maintains a Debian 12 Bookworm Linux version (10=Buster, 11=Bullseye, 13=Trixy) with it's own version of dump1090-mutability. The image can be installed on an Micro SD card. The easiest in setup is to temporarily connect a USB keyboard and HDMI screen, but the software can run headless without anything but the USB TV stick connected.
You can register the setup under it's own radar-id to feed the flight data to flightradar24 or other flighttracking services. In return you get a contributor account on flight radar.
https://www.flightradar24.com/share-your-data
Manual Setup
https://repo-feed.flightradar24.com/install_fr24_rpi.sh
losetup -f losetup /dev/loop0 /data/pi24-2.3.1.img fdisk -l /dev/loop0 mount -o loop,offset=$((512 * 532480)) -t ext4 /dev/loop0 /media/fr24/
usr/bin/dump1090-mutability --raw --write-json /run/dump1090-mutability/
Disable GUI
sudo systemctl disable --now fr24gui
Disable bluetooth
vi /etc/bluetooth/main.conf AutoEnable=false sudo systemctl disable bluetooth.service sudo systemctl disable ModemManager.service sudo systemctl stop ModemManager.service
Disable DUMP978 / UAT Feed
ls -la /usr/bin/dump978-fr24 ldd /usr/bin/dump978-fr24 cat /etc/dump978-fr24/dump978-fr24.ini sudo systemctl stop dump978-fr24 sudo systemctl disable dump978-fr24 sudo systemctl stop fr24uat-feed sudo systemctl disable fr24uat-feed
http://10.0.0.191/dump1090/gmap.html
ModeS: 486836 Callsign: KLM23N Lat: 59.93 Long: 23.86 Alt: 12375ft SQW: 3155 ModeS: 151e06 Callsign: SDM6333 Lat: 59.83 Long: 25.06 Alt: 36025ft SQW: 4314 ModeS: 4bb2b0 Callsign: THY3BP Lat: 60.23 Long: 25.17 Alt: 11000ft SQW: 4570 ModeS: 4ab56e Callsign: SAS711 Lat: 60.3 Long: 23.71 Alt: 13975ft SQW: 0245
wifi-check.sh
/usr/bin/pi.sh
ping -c 1 pi24-bookworm
arp -a | grep b8:27:eb:70:c6:94
mdns-scan