Primary Radar is used to identify targets by transmitting high-frequency signals toward it. The transmitted pulses (also called Echo) are reflected by the target and then received by the same radar. This echo SIGNAL is processed to extract target information.

On the other hand, Secondary Radar relies on the active signals transmitted by the transponder unit on the airborne target (e.g. an aircraft). Transponder is a radio receiver that receives the 1030 MHz signals (interrogation signal transmitted by Radar) and transmits 1090 MHz pulse (reply messagewith target details) back to the Radar.

 In CONTEXT of ATC: Primary Radar is both an advantage and a disadvantage. With Primary radar, even if the target is not replying the interrogation signals or does not even have transponder unit, ATC Unit can trace/locate it on the RADAR although target identification is not possible (Disadvantage). Primary radar is still used by ATC today as a backup/complementary SYSTEM to secondary radar, although its coverage and information is more limited.

Secondary Radar provides various details (LIKE object identification code, altitude, direction, speed etc.) of the target which are transmitted back by a strong response signal by the transponder.

Primary Radar is used to identify targets by transmitting high-frequency signals toward it. The transmitted pulses (also called Echo) are reflected by the target and then received by the same radar. This echo signal is processed to extract target information.

On the other hand, Secondary Radar relies on the active signals transmitted by the transponder unit on the airborne target (e.g. an aircraft). Transponder is a radio receiver that receives the 1030 MHz signals (interrogation signal transmitted by Radar) and transmits 1090 MHz pulse (reply messagewith target details) back to the Radar.

 In context of ATC: Primary Radar is both an advantage and a disadvantage. With Primary radar, even if the target is not replying the interrogation signals or does not even have transponder unit, ATC Unit can trace/locate it on the RADAR although target identification is not possible (Disadvantage). Primary radar is still used by ATC today as a backup/complementary system to secondary radar, although its coverage and information is more limited.

Secondary Radar provides various details (like object identification code, altitude, direction, speed etc.) of the target which are transmitted back by a strong response signal by the transponder.