Ham Radio General Class Test Radio Wave Propagation 5

Question 1

What is 'antenna reciprocity' as it applies to propagation path selection?

Accepted Answer

A directional antenna used for reception will have the same pattern for transmission, so the best transmit bearing is also the best receive bearing

Answer

By the reciprocity principle, an antenna's transmit and receive patterns are identical, so pointing a beam for the strongest received signal is also optimal for transmitting.

Question 2

During a geomagnetic storm, which HF bands are typically most affected?

Accepted Answer

The higher HF bands (15, 10 meters) suffer the worst degradation at high latitudes while lower bands may still work

Answer

Geomagnetic storms raise the LUF and lower the MUF, most severely impacting high-latitude paths on the upper HF bands while lower bands often remain workable.

Question 3

What is the approximate maximum distance for reliable ground-wave propagation on 40 meters?

Accepted Answer

200-500 km

Answer

Ground-wave propagation on 40 meters can reach roughly 200-500 km over average terrain; at lower frequencies like 160 meters this range extends farther.

Question 4

What is 'chordal hop' propagation?

Accepted Answer

A single very low-angle sky-wave hop that stays within the ionosphere between two points without touching Earth, enabling very long paths with low loss

Answer

In chordal hop, signals travel within the ionosphere from one point to another without returning to Earth, reducing ground-reflection losses and enabling very efficient long-distance paths.

Question 5

How does sea-water ground conductivity compare to average soil for ground-wave propagation?

Accepted Answer

Sea water is an excellent conductor and dramatically extends ground-wave range compared to average soil

Answer

Sea water has very high conductivity (~5 S/m vs ~0.005 S/m for average soil), which greatly reduces ground-wave attenuation and extends range, especially on lower HF and MF bands.

Ham Radio General Class Test Practice Test

Ham Radio General Class Test Practice Test

Ham Radio General Class Test Radio Wave Propagation 5