Final answer:
Primary radar determines the distance to objects by the time for the echoed signal to return, while secondary radar receives a transmitted response from a transponder in the target providing additional data. Enhancements in signal power and receiving sensitivity can increase radar range.
Step-by-step explanation:
The primary difference between primary radar and secondary radar systems lies in how they detect and gather information about targets such as aircraft. Primary radar transmits microwave signals and waits for the echo to return directly from objects. This allows for the determination of distance based on the time it takes for the microwave signal to return. Secondary radar on the other hand, relies on a transponder in the target to receive the signal from the radar and then actively transmit a response back. This response can provide the radar with more information, like altitude and identification code, alongside location and distance.
Improvements that can be made to a radar set to make it more sensitive include increasing the power of the transmitted signal and using more sensitive receiving equipment. An increase in power can extend the radar's range as a stronger signal can travel further and still be detectable when it returns. Enhanced sensitivity in the receiving equipment allows for weaker signals to be detected and correctly interpreted also extending the effective range of the radar.