*Question E3B10:
What is the effect of chordal-hop propagation?*  

*Correct Answer is  A: The signal experiences less loss compared to multi-hop propagation, which uses Earth as a reflector*  

### AI Response: (may contain errors)  

Chordal-hop propagation is a mode of radio wave propagation where signals travel along the ionosphere without touching the Earth's surface between hops. This is different from multi-hop propagation, where the signal reflects off the Earth between each ionospheric hop.

### Explanation of the Correct Answer:
- **Correct Answer (A):** The signal experiences less loss compared to multi-hop propagation, which uses Earth as a reflector.  
  - In chordal-hop propagation, the signal remains in the ionosphere and avoids the additional losses that occur when the signal reflects off the Earth's surface. Each reflection off the Earth introduces additional loss, so by avoiding these reflections, chordal-hop propagation results in less signal attenuation.

### Explanation of Incorrect Answers:
- **Choice B:** The MUF for chordal-hop propagation is much lower than for normal skip propagation.  
  - This is incorrect because the Maximum Usable Frequency (MUF) is not necessarily lower for chordal-hop propagation. In fact, chordal-hop can often support higher frequencies due to the reduced loss.

- **Choice C:** Atmospheric noise is reduced in the direction of chordal-hop propagation.  
  - This is incorrect because chordal-hop propagation does not inherently reduce atmospheric noise. Noise levels are more related to the frequency and the environment rather than the propagation mode.

- **Choice D:** Signals travel faster along ionospheric chords.  
  - This is incorrect because the speed of radio waves is constant in a vacuum and nearly constant in the ionosphere. The propagation mode does not affect the speed of the signal.

### Useful Concepts:
- **Signal Loss:** In multi-hop propagation, each reflection off the Earth introduces additional loss. Chordal-hop avoids these losses by staying within the ionosphere.
- **Ionospheric Propagation:** The ionosphere can support long-distance communication by refracting radio waves back to Earth, and chordal-hop takes advantage of this by minimizing ground reflections.