Question T9B03
From subelement T9 - T9B
Why is coaxial cable the most common feed line for amateur radio antenna systems?
Why is this correct?
Coaxial cable is most common because it's easy to use and requires few special installation considerations (A). While ladder line has lower loss (making B incorrect), it must be kept away from metal and requires careful routing. Coax doesn't handle the most power or cost the least (making C and D wrong), but its practical advantages—flexible routing, shielded construction that resists interference, and simple installation—make it the go-to choice for most amateur applications.
Memory tip
Look for 'practical convenience' over 'technical superiority' in amateur radio questions. The most common solution is often the most user-friendly, not necessarily the best performing. Coax wins on ease of use despite having higher loss than alternatives like ladder line.
Learn more
Coaxial cable's dominance stems from its balanced design: the center conductor carries RF energy while the outer shield provides both a return path and protection from external interference. This shielded construction allows flexible routing through buildings, around corners, and near metal objects without the careful spacing requirements of open-wire feed lines. The 50-ohm characteristic impedance matches most amateur transceivers and antennas, eliminating the need for impedance-matching networks in typical installations.
Think about it
Why do you think amateur radio operators often choose convenience over maximum performance when selecting feed lines for their stations?