What is the maximum bend radius of a coaxial cable?

• A. No more than 2 times cable diameter
• B. No more than 4 times cable diameter
• C. No more than 8 times cable diameter
• D. No more than 6 times cable diameter

Answer: (D)

When you bend coaxial cable, you’re changing the spacing between the center conductor and the outer shield and stressing the dielectric. If the bend is too sharp, the inner conductor can be pressed toward the shield and the dielectric can be compressed, causing microbends that alter the characteristic impedance, increase loss, and potentially damage the cable’s shielding. To keep signal integrity and mechanical reliability, use a bend radius large enough so the structure isn’t distorted. For most common coax, a bend radius of about six times the cable diameter is the practical minimum. This keeps the shield- conductor geometry stable and minimizes impedance variation. Radii tighter than this (2x or 4x) risk impedance changes and damage, while a much larger radius (8x) is more conservative than necessary for typical use.