Why is a Transponder code called a squawk code?

Question

When I take my friends flying, I am always asked why ATC says "Squawk 0260" for setting the transponder code to 0260 . Being an Avionics Engineer I know technically how a transponder works, but I have no idea where the term Squawk comes from lol!

Answer 1

The RAF WW2 Fighter Control System is the source of many of the terms still used in air traffic control today. To assist the RDF and D/F operators, British fighters were equipped with a simple form of transponder, which automatically replied to interrogation from the ground systems with an identification signal. Known as IFF, or Identification Friend or Foe, it identified friendly aircraft on the screens. A secret device, it was code-named 'Parrot'. The instruction to switch it on was therefore "Squawk your Parrot". That term is still in use today as modern transponder codes are known as 'Squawks'.

Answer 2

A fairly good response here from many other contributors on the basics of the transponder and it's interrogation by ATC radar. I might just add that Mode "S" which no one has mentioned also further identifies the aircraft from which the squawk code is received assigned or generic. Any aircraft operated in controlled airspace is first issued a discreet code prior to clearance into the airspace. The transponder must always be on when the aircraft is airborne unless requested by ATC. This electronic reply to interrogation is also used in technology for on-board traffic warning devices. Many aircraft today still operate without radios, transponders or other hardwired equipment but they can only fly into controlled airspace with prior approval of a route and destination by the controlling agency. There are of course provisions for continued flight in the event of equipment failure.

Answer 3

as you know it simply means set the SSR transponder to the code instructed by ATC or the GA codes. I really don't think that the term squawk really means anything I've been on both sides of this from the pilot and the nav aid side and I don't remember it being anything special. I think that it is just one of those terms that got started and everyone uses it. Like being painted by radar or the radar is painting a target, it means that we have a primary radar target.



BTW a PARROT is an artificial target used by ATC to verify that the Secondary Surveillance Radar is working. It is usually an aircraft transponder with some extra electronics to delay the response to the SSR interrogation usually to make the target seem like it is out about 100 nmi. Its to give the ATC a warm fuzzy that the radar is ok.

Answer 4

Yes, it comes form the original IFF device code-named "parrot". When the device transmits it is naturally termed "squawking", from the sound a parrot makes. Turning the device off was and is known as "strangling the parrot".

Answer 5

A quick search, not hard to do, reveals the secret.

http://forums.jetcareers.com/threads/origin-of-squawk-1200.87124/



WwII. IFF system called "Parrot" what do Parrots do, they squawk.



That same info is found in many many places with "origin of squawk code" as a SEARCH.

Answer 6

I'm guessing that the transponder is used more for general aviation flights that need to be on the radar, or occasionally spoken to by the controller.