I operate and ADS-B and UAT feeder for a number of flight tracking websites to watch aircraft near the Salina, KS airport.
I use the adsb.im feeder image, so I’m able to feed a number of sites from the same data stream. These are some of the sites I stream to:
There are others, I generally feed everything that is available in the image that I’m able to.
The system is based on a Raspberry Pi with an attic mounted 1090/978 MHz Antenna and two SDRs. The system is fed with redundant internet connections, mostly redundant network links, and a long-lasting UPS for outages.
I generally am able to track planes on the ground at KSLN, though there are a few spots on the airfield that I can’t see planes (specifically the south side of the airfield). Depending on the website, I’m usually one of only a few feeders that sees traffic in the KSLN pattern and on all sites I’m usually the only feeder seeing traffic on the ground.
The max range depends on the day, but 250nm peak range is normal for my station.
KSLN is a unique airport in that it’s the longest runway in the state of Kansas, but doesn’t see much commercial traffic. KSLN is served by SkyWest with flights to Denver, Chicago and Houston daily, but we also see flights from commercial carriers that are military charters or heading to a service company based on the airfield.
We also are near the Smoky Hill ANG Range which is operated by the Kansas Air National Guard. This range sees a number of visiting military traffic including large military exercises involving dozens of aircraft. Many of these planes lack ADS-B transponders, or they’re not required to enable them, so they don’t show up on most tracking sites.
Heavy military jets from Offutt AFB and Tinker AFB will often use the runway to practice approaches and aircraft will come for a few hours doing pattern work. These heavy jets often do have ADS-B or enough data to be located via MLAT.
Alongside the military traffic, K-State Salina has a pilot training program based on the airfield with a fleet of light aircraft that are used daily for training flights. It’s not unusual for several of these aircraft to be operating in a pattern with several more in the area on days with good flying weather.
KSLN has also been the host of a number of other events such as Aerobatic competitions, NASA missions, and more.
Yes and yes. The data is broadcast on public airwaves which are public knowledge. Aircraft owners can sign up for programs that limit what information is available publicly as well.
Military traffic can and will disable their transponders as needed as well for operational reasons.
Some tracking sites filter data to exclude aircraft that have requested not to be tracked publicly. Other sites, such as ADS-B Exchange and other smaller sites don’t remove these planes but may mark them with “LADD” or “PIA”.
Some planes may also not have an ADS-B transponder for various reasons. There are a number of exceptions that allow planes to operate without an ADS-B transponder, and other exceptions that allow them to be switched off. Some aircraft make use of other tracking methods such as UAT which don’t have the same level of coverage or may not be displayed on all sites.
In some areas, the plane might also not be picked up on any tracking station. These radio waves operate in the line of sight and can be blocked by the ground or terrain. If a plane is flying low to the ground and there isn’t any receivers nearby, the signal likely isn’t able to reach any tracking station.
MLAT stands for Multi Lateralization and is a method to track aircraft that don’t have position data in their transponder beacons. Positions are still able to be roughly calculated using timing data from the signals and comparing it to other reference aircraft.
The process is complicated, but there are a few things to know: