User's Guide

LE910Cx HW User Guide
Doc#: 1VV0301298
Rev. 13.0 Page 63 of 124 2019-07-15
GNSS Antenna Requirements
LE910Cx supports an active antenna.
It is recommended to use antennas as follow:
• An external active antenna (17dB typ. Gain, GPS only)
• An external active antenna plus GNSS pre-filter (17dB typ. Gain)
NOTE:
80502ST10950A_LE910Cx AT_Commands_Reference_Guide document
must be referred to install passive or active GNSS ANT configuration by
customer.
NOTE:
The external GNSS pre-filter is required for the GLONASS application.
The GNSS pre-filter must meet the following requirements:
Source and load impedance = 50 Ohm
Insertion loss (1575.42–1576.42 MHz) = 1.4 dB (Max)
Insertion loss (1565.42–1585.42 MHz) = 2.0 dB (Max)
Insertion loss (1597.5515–1605.886 MHz) = 2.0 dB (Max)
NOTE:
It is recommended to add a DC block to the customer’s GPS application to
prevent damage to the LE910Cx module due to unwanted DC voltage.
NOTE:
It is recommended to add PI matching network near the GPS connector on
the application board in case that RF matching is needed.
7.5.1. Combined GNSS Antenna
The use of a combined RF/GNSS antenna is NOT recommended. This solution can
generate an extremely poor GNSS reception. In addition, the combination of antennas
requires an additional diplexer, which adds significant power loss in the RF path.