Originally Posted by
Kiltie
Alpha1234 is the correct terminology. The Alpha part does not bear reference to the modes A or C available on your transponder; though I forget what it actually means!
Kiltie, I believe "Squawk A1234" does refer to the "Alpha" Mode (technically Mode 3/A) element of the SSR squawk, which is that portion of the code that you manually select. The Mode C element, which can only be selected ON or OFF, provides the altitude reporting content of the SSR response. Mode S (when fitted) is another more recent (and far more informative) part of the response.
So to say "Squawk A1234" is technically correct, although "Squawk 1234" must surely be perfectly adequate as there is little if any chance of ambiguity between the two requests.
Originally Posted by
newcomer
Kiltie,
I know Im not crazy, So I just had a very interesting read of CAP 413, Page 97 of 198 states very clear
Phase "Squawk Charlie"
Meaning " Select altitude reporting feature"
There is no mention at all about squawking Alpha .
newcomer, "Squawk" effectively means "Squawk Alpha" because by simply turning the Transponder to "On", you are asking it to respond to any Mode A interrogation received. You cannot inhibit Mode A except by switching the unit to STBY or OFF whereas Mode C (or Mode S when fitted) may be selectively activated or suppressed. Hence the "Squawk Standby" and "Stop Squawk Charlie" instructions.
For anybody still awake
, a far more detailed technical treatise on Secondary Surveillance Radar (SSR) can be found
here ...
JD
