Question T9B10
From subelement T9 - T9B
What is the electrical difference between RG-58 and RG-213 coaxial cable?
Why is this correct?
RG-213 cable has less loss at a given frequency because it's physically thicker with better construction than RG-58. Both cables have 50-ohm impedance, but RG-213's larger diameter and superior design reduce signal loss. RG-58 is more flexible but lossy, while RG-213 sacrifices some flexibility for significantly better performance. This makes RG-213 ideal for longer runs and higher frequencies where minimizing loss is critical.
Memory tip
Remember the thickness pattern: thicker coax generally means lower loss. When comparing any two coaxial cables with the same impedance, the physically larger one typically performs better at preserving signal strength, especially important for VHF/UHF operations.
Learn more
In practical amateur radio installations, this loss difference becomes significant on longer feed line runs or at higher frequencies. A 50-foot run of RG-58 to a 2-meter antenna might lose several decibels compared to RG-213, directly impacting your effective radiated power and received signal strength. Professional repeater installations almost always use low-loss cables like RG-213 or hardline to maximize system performance and coverage area.
Think about it
Why do you think satellite dish installations often mount the receiver electronics directly at the antenna rather than using long coaxial runs back to the house?