Ham Radio General Class Practice Test

What problem can occur when making measurements on an antenna system with an antenna analyzer?

1. SWR readings may be incorrect if the antenna is too close to the Earth

2. Strong signals from nearby transmitters can affect the accuracy of measurements

3. The analyzer can be damaged if measurements outside the ham bands are attempted

4. Connecting the analyzer to an antenna can cause it to absorb harmonics

The correct answer is: Strong signals from nearby transmitters can affect the accuracy of measurements

When using an antenna analyzer, one critical issue that might arise is the influence of strong signals from nearby transmitters, which can affect the accuracy of measurements. An antenna analyzer works by sending a small test signal through the antenna system and measuring various parameters, such as standing wave ratio (SWR) and impedance. If there are powerful signals from nearby transmitters, they can introduce interference and cause the analyzer to provide misleading readings. The presence of these strong signals can overload the analyzer, leading to incorrect assessments of the antenna's performance. In contrast, other factors mentioned in the choices do not directly pertain to the fundamental functionalities of antenna analyzers. For example, while SWR readings can be affected by proximity to the Earth, this condition often influences the ground effects rather than the analyzer's operation itself. Additionally, even though measuring outside of ham bands may pose risks to the analyzer, this is more about the potential damage than a measurement accuracy issue. Similarly, the concern about absorbing harmonics might be relevant in specific contexts, but it does not directly impact the primary focus of making real-time measurements effectively. Thus, the risk associated with strong signals is the most directly applicable problem while using an antenna analyzer.