Coaxial cable and bend radius- what does it mean?

June 29, 2022

If you are in the market for coaxial cable, you have some choices. There are different shielding grades, and there is also standard grade vs. super flex or ultraflex (UF)

Shielding grade has to do with how much dB loss you will get. The thicker the cable, the less loss, but the more difficult the cable will be to bend. 

Standard grade 400 coax, such as Times Microwave LMR-400, RFC-400 etc. has a minimum bend radius of 4 inches. This means it should not be bent around something with a radius under 4 inches, which you can simulate by thinking of a pole that is 8 inches in diameter. This would have a radius of 4 inches. 

Ultraflex and Super Flex cables are made of a flexible material that allows a lower bend radius. The one-time minimum bend radius of this type of cable is 1 inch, which means you can go around a corner with a radius of 1 inch, which you can simulate by thinking of a pole that is 2 inches in diameter.

What is meant by 1-time would mean at a certain segment you can make the bend, but don't coil it at this same radius.

What happens if you go below the bend radius?

These cables are made with copper coated aluminum center conductor wire. Going below bend radius may not immediately break the cable but can weaken it's integrity. Think of a paperclip bent back the wrong way. It still stays together, but bend it back and forth a few times and it can snap. So avoid going below the bend radius of your cable. If you need a better bend radius, ultra flex or super flex is the way to go. 

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