Enable Mode A/C

The "to-do" list for Virtual Radar Server is as long as my arm, but if you want to pile more work onto it then this is for you.
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Joined: Sat Mar 21, 2015 8:52 pm

Enable Mode A/C

Post by ricreig » Mon Jun 01, 2015 6:11 pm

Hi, there is any way i can see the mode a/c airplanes with the squawk code or altitude around, i have a VRS with 1 Flight Radar24, 2 Flight Feeders from Flight Aware and 2 Pi Aware receivers, all working only at ADS-B and Mode-S, but i can see there is a posibility into the internet, so anyone ¿¿

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Joined: Fri Feb 17, 2012 3:20 am

Re: Enable Mode A/C

Post by agw » Sat Jun 06, 2015 2:33 pm

Mode A and Mode C messages are indistinguishable from each other and they don't have the aircraft's ICAO-24 code on them, so there's not much that can be done with them.

This guy has a write-up of Mode A and C messages: http://www.airsport-corp.com/modec.htm
There is no difference between a Mode A and Mode C reply. If a Mode A interrogation is issued, a Mode A reply is expected, and the pulses will be decoded that way. Likewise, if a Mode C request is made, the data received from the aircraft will be calculated as altitude. This works well with only one ground station, but with several stations interrogating the same aircraft, mistakes can and do occur.

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