Question T4A03
From subelement T4 - T4A
Why are short, heavy-gauge wires used for a transceiver’s DC power connection?
Why is this correct?
Short, heavy-gauge wires minimize voltage drop when transmitting because they have lower resistance than long, thin wires. When transmitting, transceivers draw high current, and any resistance in the power cables causes voltage to drop between the power supply and radio. If voltage drop is too large, the transceiver can malfunction. Options B and C are incorrect—DC power wires don't function as antenna counterpoises, and RF interference is addressed through different methods like ferrite cores and shielding.
Memory tip
Remember the pattern: high current applications always require low-resistance connections. When you see questions about heavy-gauge or short wires in power applications, think 'minimizing resistance to handle high current flow.' This principle applies across amateur radio—from power connections to RF grounding systems.
Learn more
Voltage drop follows Ohm's Law principles—when current increases during transmission, any resistance in the power path becomes problematic. Mobile installations are particularly vulnerable because longer cable runs to trunk-mounted radios increase resistance. Understanding this helps explain why amateur radio power distribution systems use heavy conductors, why bonding straps are flat copper, and why battery connections use large terminals. This knowledge transfers to designing reliable station power systems and troubleshooting power-related performance issues.
Think about it
Why do you think voltage drop becomes more critical during transmission than during receive, and how might this affect a transceiver's power output capability?