Mode S Transponder

[tangocharlie123]

Hi All

 

I am new to transponders and was wondering what is the difference between a mode c and mode s transponder

 

I was wondering if you can use a transponder from overseas like http://www.trig-avionics.com/tt21.html this also has the adsb out will this be any use in the future.

 

Cheers

 

 

[Guest pelorus32]

Three modes:

 

• Mode A - the Squawk Code assigned by ATC or the VFR code or the emergency codes
   
   
  
• Mode C - the Altitude Code. Modes A and C are almost always found together though Mode A was developed before Mode C;
   
   
  
• Mode S - this provides an individual code for the airframe and also provides Mode A (on second thoughts Mode A is replaced by Mode S I think) and C capability.
   
   
  

 

 

See here for description of Mode S: Mode S technology

 

ADS-B relies on a type of Mode S transponder and comes in at least 2 Standards and 2 capabilities.

 

The capabilities are ADS-B Out and ADS-B In. It also requires a GPS source. Out simply sends your ADS-B data whilst In also allows a Cockpit Display of Traffic Information (CDTI) to display info on other a/c.

 

The Standards are 1090ES (for 1090Mhz Extended Squitter) which is the chosen Australian Standard and the other standard that they are going to use in the US - name evades me atm. But of course they are incompatible:sad:.

 

A standard Mode S is interrogated on 1030 from memory and responds on 1090 but doesn't have the ES.

 

It appears however that the Trig is 1090ES so that's good, however it only does ADS-B out if that matters.

 

Regards

 

Mike