ARRL Technician Practice Exam

What is a good reason not to use a "rubber duck" antenna inside your car?

1. It is less durable than other types

2. Signals can be significantly weaker than when it is outside of the vehicle

3. It is not designed for mobile use

4. It creates excessive noise interference

The correct answer is: Signals can be significantly weaker than when it is outside of the vehicle

Using a "rubber duck" antenna inside your car is not ideal primarily because signals can be significantly weaker than when the antenna is positioned outside the vehicle. The environment inside a car, which includes metal surfaces and various electronic components, can create a barrier that adversely affects radio signal propagation. When the antenna is outside, it has a clearer path to transmit and receive signals, resulting in a stronger and more reliable communication link. This decrease in signal strength can lead to difficulties in effective communication, including reduced range and clarity. The physical characteristics of the "rubber duck" antenna, which is typically designed for portable use, are optimized for outdoor placement. When used inside, it cannot effectively radiate or receive signals compared to when it’s placed in an unobstructed outdoor location. While factors such as durability, design for mobile use, and noise interference could be considerations, those factors do not have the same pronounced impact on signal quality as the issue of reduced signal strength when the antenna is kept inside the vehicle.