Question T6D03
From subelement T6 - T6D
Which of the following is a reason to use shielded wire?
Why is this correct?
Shielded wire contains a conductive layer (shield) around the inner conductor(s) that acts as a barrier against electromagnetic interference. This shield prevents unwanted external signals from coupling into your wire and also prevents your signals from leaking out to interfere with nearby equipment. Options A and B are incorrect because shielding doesn't affect resistance or current capacity - those depend on the wire gauge itself. Option D is backwards - shielding prevents coupling, not promotes it.
Memory tip
Remember the key pattern: shielding is always about isolation and protection. When you see 'shielded' in amateur radio contexts, think 'barrier against interference.' The shield acts like a Faraday cage around your signal path, keeping wanted signals in and unwanted signals out.
Learn more
Shielded cables are essential in RF environments where multiple signals coexist. The shield connects to ground at one end, creating a return path for induced currents that would otherwise become noise. This is why coaxial cable uses shielding - it maintains signal integrity by preventing radiation losses and pickup of external interference. Proper shield grounding prevents ground loops while maintaining the isolation benefits.
Think about it
Why do you think shielded wire is especially important in amateur radio applications compared to simple household wiring?