Originally Posted by
A320 Glider
Will ATC be able to see the 7500 code whilst I'm turning the knobs of the transponder?
No , normally not, you may but in very exceptional circumstances , i.e you will have to pause significantly while passing through this exact number , and the radar antenna has to be hitting you right at that moment , but remember the rpm of a typical en route radar is 12 Rpm. so hitting you for a nanoseconds every 5 seconds . so you will have to be extremely unlucky to have this ,I personally never seen it in my whole career ,
In addition , quite a few ATM systems have a filter that needs at least 2 returns to confirm an anomaly , especially on the mode C ., to avoid garbling and false alerts , in this case no chance for ATC to see your "intermediate " codes.
@Dixi188 :
Always used to select STBY before changing squawk.
Shows your age
, a bad habit today as most ATC systems run on SSR only and you will then briefly disappear from view, it will also delay TCAS reactions . ,and on the ground, multilateratuion protections from vehicles depends on having your transponder on at all times..( for those airports equipped)