Question T9A04
From subelement T9 - T9A
What is a disadvantage of the short, flexible antenna supplied with most handheld radio transceivers, compared to a full-sized quarter-wave antenna?
Why is this correct?
The correct answer is A because handheld 'rubber duck' antennas use inductive loading to make them physically shorter than a full quarter-wavelength. This loading process inherently reduces efficiency compared to a full-sized quarter-wave antenna. The other options are incorrect: these antennas don't transmit only circularly polarized signals (B), and mechanical fragility (C) isn't their primary disadvantage compared to efficiency loss.
Memory tip
Look for 'loading' in antenna descriptions—it's almost always a trade-off between size and efficiency. When manufacturers make antennas smaller through electrical tricks like inductive loading, they sacrifice performance for portability. This size-versus-efficiency pattern appears throughout amateur radio antenna design.
Learn more
Handheld antennas demonstrate a fundamental compromise in portable amateur radio equipment. The 'rubber duck' antenna's inductive loading allows it to function as a resonant radiator despite being physically much shorter than a quarter wavelength. However, this electrical lengthening introduces losses that reduce radiation efficiency. In mobile or base station applications, external quarter-wave or 5/8-wave antennas provide significantly better performance because they can achieve resonance without artificial loading methods.
Think about it
Why do you think manufacturers still include these less efficient antennas with handheld transceivers instead of providing full-sized quarter-wave antennas?