When installing coax cable you need to know the distance of the run for the maximum coax cable lengths due to the attenuation of the L band RF signal and voltage drop on the coax cable between the outdoor equipment (antenna, BUC, LNB) and the indoor unit (modem, antenna control unit ACU). The correct cable needs to be installed depending on the distance/length of the run to account for these losses.
The manufactures cable spec will show the loss (in dB) per metre so it’s easily calculated.
Distance markers are printed on the outer sheath of a cable in meters, so you can work out the length when installing or if it’s already been installed. If you are having issues with an install it’s always worth checking the cable lengths and comparing it to the recommended lengths. The cable type will also be printed on the outer sheath.
Coax Outer Sheath Markings
- Meter markers
- Manufaturer
- Cable Type
- LSZH (Low Smoke Zero Halogen)
- Any Standards i.e. British Standard
- Number and nominal size of cable cores
- Year Letter
- Country of origin
- Harmonised Core Colours
Coax Cable Lengths
Here are some 50Ω coax cables maximum lengths as recommended by Intellian.
[su_table responsive=”yes”]| Coax Cable Type | Attenuation in dB/100m | Attenuation in dB/m | Recommended Cable Length |
| LMR300 | 30.3 | 0.303 | 35m |
| LMR400 | 19.6 | 0.196 | 60m |
| LMR500 | 15.9 | 0.159 | 80m |
| LMR600 | 12.8 | 0.128 | 100m |
| LMR900 | 8.6 | 0.086 | 150m |
| LMR1200 | 6.5 | 0.065 | 200m |
The most commonly used coax for VSAT installs is LMR400 or LMR600. RG6 and RG11 are also used and are 75Ω.
