SSR Flashcards
SSR principle
Moded and coded pulses
SSR Frequency
1030MHz-1090MHz
SSR Frequency band
UHF
Transmitter transmits pair of pulses at ___ freq
1030MHz
Transponder replies to interrogation at ___ freq
1090MHz
A/C responds to interrogation in the form of __
2 framing pulses F1 and F2
Time interval b/w pulse 1 and pulse 2
2 microseconds (always ie fixed)
Time interval b/w pulse 1 and pulse 3 decides___?
Mode
It is called mode determining spacing
Mode A interval b/w P1 and P3 and use
8 microseconds
Used only for a/c identification
Mode B interval b/w P1 and P3 and use
17microseconds
Not in use
Mode C interval b/w P1 and P3
and use
21microseconds
Used for
1)Identification and
2)Pressure altitude (1013.25 hPa)
P2 transmitted for___
Side lobe separation
In Special positioning identifying pulse (SPI), upon pressing Squawk ident button the pulse beeping will been for___
20seconds continuously
In SPI, when does pulse blip for 20seconds ?
AFTER the last framing pulse
Mode C provides
Pressure altitude 1013.25hpa
AC ident
In case of Discrepency of ___feet b/w altimeter of ac and mode C transponder
+/- 300ft
+/- 300ft diff in mode c and pressure altimeter. What should be turned off
Mode C should be turned off
Number of codes available in mode C
4096
Numbers omitted from SSR codes
7 and 8 not used
Code 7500
Hijacking / unlawful interference
Code 7600
Radio failure / communication failure
Code 7700
Distress/ emergency
Code 0000
Transponder failure
Code 2000
No code allotted
Code 1200
VFR
Mode C altitude read out ?
+/- 50feet
Mode S altitude read out
+/- 25 feet
Mode S number of available codes
16 million
2 Advantages of mode S
Reduces RT workload
Data link communications
