LMR-400 Cable Insertion Loss Calculator

This tool computes the attenuation loss in dB of a user-specified length of LMR-400 RF coaxial cable [1].

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 LMR195, LMR1700 – 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-400?

LMR-400 cables are typically used in antenna systems where high performance and low loss are required. There are 6 different types of LMR cables:

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

The main difference between these different LMR400 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.


Once the attenuation or insertion loss is calculated, it can be used in the antenna range calculator. In general, the higher the attenuation the lower the range.


[1] Coaxial Cable on Wikipedia