Ham Radio General Class Practice Test

What is one disadvantage of using a shortened mobile antenna as opposed to a full size antenna?

1. Short antennas are more likely to cause distortion of transmitted signals

2. Short antennas can only receive vertically polarized signals

3. Operating bandwidth may be very limited

4. Harmonic radiation may increase

The correct answer is: Operating bandwidth may be very limited

A shortened mobile antenna is designed to be more compact and portable compared to a full-size antenna, which can be advantageous for mobile operations. However, one notable disadvantage is that the operating bandwidth may be very limited. This limitation arises because the physical size of the antenna affects its resonance and efficiency. Full-size antennas are typically able to cover a wider range of frequencies effectively due to their length, which allows them to resonate better. In contrast, shortened antennas often need to be tuned to specific frequencies, and they may only perform well over a narrow band. This means that operators using a shortened antenna might experience difficulties when attempting to transmit over frequencies outside that specified range, which can restrict operational flexibility and effectiveness. The other options address different factors related to antenna performance but do not directly correlate with the fundamental issues that result from the shortened length of the antenna impacting its bandwidth capabilities.