ADS B(S) - posssss/portapack-mayhem GitHub Wiki

This is a potentially dangerous App. The HackRF could be used to generate valid ADS-B messages and if these are radiated then it could effect both how aircraft and navigation systems see each other. Therefore, it should only be used in a closed RF environment or when there is no direct transmission.

The Key Items on the App that can be selected with the cursor and changed with the encoder knob are:

  • Title bar: The usual Items may be changed and displayed.
  • Tab pages: The Tab pages for the settings that are can be selected are Position, Callsign, Speed, Squawk. This data is not held in persistent memory except for the frequency.

Position Tab

ICAO24: This code is selected with rotary encoder to enter the 6 digit numeric number. This is sometimes called the Mode S code and is a 24-bit unique number that is assigned to each vehicle or object that can transmit ADS-B messages. It is usually transmitted by aircraft but some airport ground vehicles and multi-lateration towers also have ICAO24 codes assigned to them. Transmit position: this is a tick box to enable the transmission of Alt. Lat. Lon

  • Alt: Sets height in feet.
  • Lat: Setting of Latitude is in Degrees Minutes and Second and set with encoder knob. The numeric value is given to the right hand side
  • Lon: Setting of Longitude is in Degrees Minutes and Second and set with encoder knob. The numeric value is given to the righthand side.
  • Set from Map: the Lat and long can be set form the map view and using the touch screen if desired. Note to save the value is a “OK” button but this is hidden behind the Digital values of the Lat and Lon. But if you touch this, are it will appear.

Callsign Tab

  • Transmit callsign: This is a tick box to turn on the transmission of the Callsign. The callsign is entered in the text pad and is 8 characters long.

Speed Tab

  • Transmit speed: This is a tick box to turn on the transmission of the speed.
  • Speed: The value is selected and the rotary encoder is used to select the value 0-999kn, unit: knots.
  • Bearing: The value is selected and the rotary encoder is used to select the value 0-359 Degrees. (to be more friendly user, the input bearing angle direction is also displayed in the top right Compas circle UI)
  • Vertical Rate: The value is selected and the rotary encoder is used to select the value -4096 to +4096 ft/min in steps of 64 (following the encoding standard). It indicates the vertical rate speed of the plane (+) climbing , (-) descending. In real plane ,that Vr source data information can come from GNSS or Barometric altitude equipment. In mayhem fw , we are simulating a fix source from GNSS. Example about climb vert. rate (+) : The Cessna 172 is a four-seat aircraft. At maximum weight it has a VY of 75 kn (139 km/h) indicated airspeed4(https://en.wikipedia.org/wiki/Rate_of_climb#cite_note-4) providing a rate of climb of 721 ft/min (3.66 m/s) ). Example about descend vert. rate (-): The profile varies from airport to airport, but generally, around five miles from the runway, the airplane is at landing speed, with slats/flaps in the landing position, vertical descent speed less than 1,000 feet per minute and the engines powered up properly.

Squawk Tab

  • Transmit squawk: This is a tick box to turn on the transmission of the Squawk code.
  • Squawk: A discrete transponder code (often called a squawk code), can be selected with rotary encoder and has specific meanings. The system identifies an aircraft through a four-digit octal number. (each digit number from 0-7), which provides up to 4.096 possilbe codes. The squawk code range is from 0-7777.
    Squawk codes are usually random, but there are a handful of specialized squawk codes that are reserved for unique or specialized situations or aircraft. https://en.wikipedia.org/wiki/List_of_transponder_codes

Some public pilot user interface equipment examples (from Wikipedia),

image image

Common to all Tabs

  • Frequency: At the lower part of the App is the Frequency setting. This is stored in persistent memory
  • Step size: This is next to the frequency and allows the selection of the standard step sizes.
  • Gain: The gain setting are below the frequency and marked (0-47) LNA(IF) and AMP 0=0db or 1=14dB.
  • Start: This button starts the transmission and if pressed again can stop the transmission.