The Sierra Wireless GX400 and GX440 have an additional antenna port for Rx Diversity. Rx Diversity is designed to improve the quality of the downlink signal by essentially enabling the device to “choose” the best available signal. Rx diversity has been shown to improve signal quality. However, many customers decide to forego the expense of the 2nd antenna and rely on one Rx signal. Rx Diversity is set to “”ON”” by default in ALEOS, but if you decide to not use a 2nd antenna it’s vital to change the ALEOS setting for Rx Diversity to “OFF”. This setting can be found under the “WAN/Cellular” tab in ACEmanager 4.0.
The GX440 (LTE) utilizes 2×2 MIMO technology. MIMO equals Multi-In/Multi-out and is designed to improve the cellular signal and quality on both the down-link and up-link. MIMO for LTE works differently than Rx Diversity in that it utilizes 2 distinct Tx and Rx signals which are intelligently combined to increase throughput where signal multipath is available. MIMO will increase throughput in areas where interference would otherwise cause throughput degradation. Our recommendation is that 2 antennas be used for optimal performance. A single antenna may be used, however with one antenna you will not receive full MIMO benefits and your antenna performance may not be optimized. It is up to the user to determine if two antennas are beneficial, as multi-path is determined by local topology. There is no option to turn MIMO off in the GX440 since MIMO is a requirement of LTE.
Please contact your USAT Sales Manager for help identifying your best antenna options and to learn more about our custom cable assemblies and jumpers.