LMR 240 Cable Loss Calculator

This tool computes the attenuation (in dB) of a user-specified length of LMR-240 [1] RF coaxial cable [2].

To use the insertion loss calculator use the tool below. Enter

  • Cable length and the units (feet/inches/meters)
  • Frequency of operation in MHz


LMR cables are made by Times Microwave. They come in different varieties differentiated by a numerical suffix. For instance LMR200, LMR600 – each with different electrical attributes. The frequency of operation can be as high as 8 GHz making them suitable for everything from HF to Wi-Fi 6e.

The cable has an outer conductor (shield) and an inner conductor (coaxial cable), which are separated by a dielectric material. The cable also has a Jacket (outer cover) that protects the inner conductors from environmental damage.

What is LMR-240?

LMR-240 cables are typically used for Jumper Assemblies in Wireless Communications Systems, short antenna feeder runs and any application that requires low loss cable.

There are 6 different types of LMR cables:

  • LMR-240
  • LMR-240-DB
  • LMR-240-FR
  • LMR-240-FR-PVC
  • LMR-240-PVC
  • LMR-400-PVC-W
  • LMR-240-MA

The main difference between these different LMR 240 cables is in the jacket material and color.

The longer the cable the greater the insertion loss. As well, insertion loss increases with operating frequency.

What does LMR stand for?

LMR stands for Land Mobile Radio. Typical LMR frequencies are in the VHF and UHF (30 MHz to 512 MHz) range. However LMR cables can be used for frequencies up to 8 GHz.


[1] LMR 240 data sheet from Times Microwave

[2] Coaxial Cable on Wikipedia