A radar transponder is a radio beacon on an aircraft that replies to a radar interrogation. The transponder encodes information into the reply, allowing air traffic control to know the aircraft's altitude and identity.
Questions tagged [transponder]
109 questions
43
votes
6 answers
Why is the range of transponder digits 0 to 7 rather than 0 to 9?
As a controller on IVAO I sometimes assign codes like 0168 and find out later that the code isn’t valid. For me, the range 0-9 seems more logical. Why do we have to use octal numbers and not decimal?
Hugo Woesthuis
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Should I switch the transponder to STBY or not while changing codes?
I´m now reading Bob Gardner’s book “Say again, please” and there is this instruction on page 54:
Do not turn the transponder function switch to STBY while changing codes.
What is the reason for this? I’m a PPL student and my instructor told me…
Hask S.
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10
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3 answers
What is the ICAO 24-bit code used for?
I know that each transponder is linked to a unique 24-bit code assigned by ICAO. But to be seen by the Secondary surveillance radar the pilot set the squawk code (4 digit octal code) on the transponder as dictated by the Air Traffic Controller…
Gianni Alessandro
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How can I ensure that I have a mode C transponder?
How can I make sure my aircraft is equipped with a mode C transponder?
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If a transponder has an ALT button does that mean that the aircraft is equipped with MODE C?
FAN
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5
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Is there a relation between the Mode 3/A Code and the ICAO aircraft address?
I would like to know is there is any way to match mode 3/a code (which is assigned by ATC to aircraft) and ICAO address of the aircraft. I mean how mode 3/a code is assigned to each aircraft by ATC? Is that unique for that day or certain time…
Asma
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Why is Mode C helpful for ASDE-X systems?
Airports that operate an ASDE-X system require aircraft to operate transponders in mode C while moving on the surface.
While I understand the general purpose of operating the transponder to correlate with the other information ingested by the…
TelegraphOperator
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