Thanks for your support, Jan, but ST is correct with a total of 4096. Old age and dementia are obviously creeping up on me ! :ouch:

That's because most of the USA is Class E airspace where IFR flight is mandatory and hence an individual code is allocated..

Used to be used where the ATC unit involved did not have labels on its radar display, just an extra 'blip' along with the primary blip.

The code 'Alpha 00' (aka 0000) was commonly used in some areas when identifying traffic operating in the airspace above FL245 when I was controlling civil traffic at Northern Radar (RAF Lindholme) up until mid 1973.

Staxton Wold is a radar station 'somewhere in England' and if I told you about it I'd have to kill you.:mad:

Stationary transponder testing has been taking place in the Scottish Western Isles for months.

Was also tested many years ago at (I think) RAF Halton.

IFR isn't mandatory it's mixed IFR/ VFR ( that's why it is recommended to continue the "see and avoid policy).

Now the purpose of class E is, at certain minimums, to have everyone on IFR below those minimums.
I forgot to say but, 1200 is the VFR squawk

I'm confused, what does strangle the parrot mean 🦜?

Squawk standby - because the early IFF kit was code name "Parrot"

A bit like "kill the rabbit" :ok:

many thanks ETOPS

And they have the nerve to criticize our phraseology! And we even gave up our "taxi into position and hold".... saying "conspicuity" sounds like trouble....Muppettry of the finest kind.