decode Mode A/C

[jayyang]

Is it possible to decode Mode A/C using AirNav RadarBox to identify the military airplanes?

[Runway 31]

Yes but only if they are displaying a hex code, the hex code is known and it is in the database, just like a civil aircraft.

Alan

[ACW367]

Jayyang

You may be getting slightly confused here.  The answer is actually No.  No aircraft that only have Mode A/C will ever be displayed on Radarbox, the Radarbox can only decode Mode S.  It has no capability to decode Mode A/C although is does display the 4 digit octal Squawk code from these modes as long as the aircraft is also tranmitting Mode S.  Mode A/C squawk codes are allocated by Air Traffic Control authorities and have no correlation to airframe identity.

Mode A just displays the 4-digit octal squawk code.
Mode C displays the 4 digit octal squawk code and also will report pressure altitude.
Mode S is the one based on the 24-bit binary Aircraft Allocation code which is displayed as six-character hex for the code we use and includes all the additional information on aircraft identity, callsign, heading, speed etc. If it is ADS-B it will also broadcast position to enable it to plot on the Radarbox map.

A mode S equipped aeroplane will also also transmit a Mode C Squawk.

If military aircraft are fitted with Mode S, they will be picked up and identified on Radarbox, although if not fitted with ADS-B they will not display a position.

Any civil or military aircraft that is only fitted with Mode A/C and not equipped with Mode S will be completely invisible on Radarbox and will never appear on the system.

These pages will explain more.
http://en.wikipedia.org/wiki/Transponder_(aviation)
http://en.wikipedia.org/wiki/Mode_S#Mode_S

[jayyang]

Many thanks to ACW367. your answer really make me more clearly understand the difference between mode A, mode C and mode S.