HE920 Hardware User Guide
1vv0301014 Rev.9 – 2014-01-23
Reproduction forbidden without written authorization from Telit Communications S.p.A. - All Rights
Reserved.
Page 46 of 84
NOTE:
The external GNSS LNA and GNSS pre-Filter shall be required for GLONASS application.
GNSS LNA requirement shall fulfill the following specifications.
Frequency = 1565 – 1606MHz
Power Gain|S21|
2
= 14 – 17dB
NF < 1dB
GNSS pre-Filter requirement shall fulfill the following requirements.
Source and Load Impedance = 50Ohm
Insertion Loss (1575.42 – 1576.42MHz) = 1.4dB (Max)
Insertion Loss (1565.42 – 1585.42MHz) = 2.0dB (Max)
Insertion Loss (1597.5515 – 1605.886MHZ) = 2.0dB (Max)
WARNING:
The HE920 software is implemented differently depending on the configurations of an
external device. Please refer to the AT command User Guide in detail.
The external active antenna for the Telit HE920 device must fulfill the following
requirements:
ACTIVE GPS/GNSS Antenna Requirements
Frequency range
GNSS(GPS L1 & GLONASS) : 1565 MHz ~ 1606 MHz
GPS L1 : 1575.42MHz
GLONASS : 1597.55 – 1605.89MHz
Bandwidth
GPS L1 : +/- 1.023MHz
GLONASS : 8.34MHz
Impedance
50 Ohm
LNA NF
< 1dB
LNA Gain
14 ~ 17dB
LNA Input Voltage
3.0V or 5.0V
NOTE:
The maximum DC voltage applicable to ANT_GPS pin is 5V. In case this is exceeded, a
series capacitor has to be included in the design to avoid exceeding the maximum input DC
level.
