*Question E2E12:
How do ALE stations establish contact?*  

*Correct Answer is  A: ALE constantly scans a list of frequencies, activating the radio when the designated call sign is received*  

### AI Response: (may contain errors)  

To understand how ALE (Automatic Link Establishment) stations establish contact, let's break down the correct answer and the other options.

### Correct Answer: 
**A: ALE constantly scans a list of frequencies, activating the radio when the designated call sign is received.**

- **Explanation**: ALE systems are designed to automatically scan a pre-programmed list of frequencies. When an ALE station hears a call sign that matches its own, it activates the radio to establish a communication link. This method allows for efficient and reliable contact without manual tuning.

### Why the Other Choices are Incorrect:

- **B: ALE radios monitor an internet site for the frequency they are being paged on.**
  - **Explanation**: ALE does not rely on internet connectivity for frequency monitoring. It operates independently of the internet, using radio frequencies to establish connections.

- **C: ALE radios send a constant tone code to establish a frequency for future use.**
  - **Explanation**: While ALE may use tones for signaling, it does not send a constant tone code. Instead, it scans frequencies and listens for specific call signs to initiate contact.

- **D: ALE radios activate when they hear their signal echoed by back scatter.**
  - **Explanation**: Back scatter refers to signals bouncing off the ionosphere or other surfaces, but ALE does not depend on this phenomenon for activation. It relies on direct reception of the designated call sign.

### Summary:
- ALE stations use a scanning method to listen for their specific call sign on a list of frequencies, allowing for automatic and efficient communication setup.
- Other options either misrepresent the functionality of ALE or introduce concepts that are not applicable to its operation.

This understanding of ALE will help you answer related questions on the Extra Class exam effectively.