*Question G8A13:
What is a link budget?*  

*Correct Answer is  C: The sum of transmit power and antenna gains minus system losses as seen at the receiver*  

### AI Response: (may contain errors)  

A link budget is a calculation used to determine the performance of a radio communication link. It accounts for all the gains and losses from the transmitter to the receiver.

### Correct Answer: C

- **Explanation**:  
  A link budget is the sum of the transmit power and antenna gains, minus the system losses, as seen at the receiver. This calculation helps determine if the received signal strength will be sufficient for reliable communication.

- **Formula**:  
  The basic link budget formula is:  
  $$ P_R = P_T + G_T + G_R - L_P - L_S $$
  where:
  - $P_R$ = received power
  - $P_T$ = transmit power
  - $G_T$ = gain of the transmitting antenna
  - $G_R$ = gain of the receiving antenna
  - $L_P$ = path loss
  - $L_S$ = system losses (e.g., cable losses, connector losses)

### Why Other Choices Are Incorrect:

- **Choice A**:  
  "The financial costs associated with operating a radio link" is incorrect because a link budget is not about financial costs; it is a technical calculation related to signal strength and quality.

- **Choice B**:  
  "The sum of antenna gains minus system losses" is incorrect because it omits the transmit power, which is a crucial component of the link budget.

- **Choice D**:  
  "The difference between transmit power and receiver sensitivity" is incorrect because it does not account for antenna gains or system losses, which are essential parts of the link budget calculation.

Understanding the link budget is crucial for ensuring that a communication link will function as intended, with sufficient signal strength at the receiver.