Antenna positioning

This article applies to Orbital hardware installations where a cellular antenna is used with a modem to provide mobile data connectivity to OrbiSCADA. Antenna positioning has a large impact on connection quality. A modem may still connect with a poorly positioned antenna, but the connection can become weak, unstable or intermittent. An antenna mounted inside the tower may work, but signal strength can drop significantly compared to the same antenna mounted just a few meters outside the tower wall.

What affects signal quality?

• Line of sight to the nearest cellular base station. The fewer steel and concrete obstructions between the antenna and the network, the better.
• Height above ground. Higher placement generally improves reception, especially in rural or remote sites.
• Distance from large metal objects. Even outside the tower, an antenna mounted directly against a steel surface will perform worse than one mounted on a short standoff bracket.

In weak-signal areas, moving the antenna outside the tower is often the single biggest improvement you can make.

Cable length considerations

Moving the antenna outside normally requires a longer antenna cable, and longer coaxial cables introduce signal loss. Industry antenna guidance generally recommends keeping antenna cables as short as practical, and using low-loss cable when longer cable runs are required.