Advanced Qualification · A-007 Feedlines and matching · A-007-007-003
The plane from which ground reflections can be considered to take place, or the effective ground plane for an antenna is:
- A as much as a meter above ground
- B at ground level exactly
- C several centimeters to as much as 2 meters below ground, depending upon soil conditions
- D as much as 6 cm below ground depending upon soil conditions
Correct answer: C — several centimeters to as much as 2 meters below ground, depending upon soil conditions. From the official ISED question bank, verified word for word.
Why
The effective ground plane is not the dirt surface you see, but a virtual layer where radio waves appear to bounce, located anywhere from a few centimetres to two metres below the actual ground. The full explanation — and one for every question — is in Pro.
Practise this section
Feedlines and matching at the advanced level: transmission line theory, impedance transformation, stubs and matching networks.