User's Manual

Smart Machine Smart Decision
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4.3. Module GPS Receiver Performance
The following table shows the module’s conducted TTFF(Time To First Fix) and receive sensitivity, it is tested
under static condition.
Table 12: SIM808 conducted GPS Performance
Parameter Description Performance (Type)
Autonomous acquisition(cold
start)
-148dBm
Re-acquisition -159dBm
Sensitivity
Tracking -165dBm
Hot start <1s
Warm start 28s
Time To First Fix
Clod start 30s
4.4. Module Operating Frequencies
The following table shows the module’s operating frequency range; it is followed by the 3GPP TS 05.05 technical
specification requirement.
Table 13: SIM808 operating frequencies
Frequency Receive Transmit
GSM850 869 ~ 894MHz 824 ~ 849 MHz
EGSM900 925 ~ 960MHz 880 ~ 915MHz
DCS1800 1805 ~ 1880MHz 1710 ~ 1785MHz
PCS1900 1930 ~ 1990MHz 1850 ~ 1910MHz
GPS 1575.45±2MHz N/A
5. Antenna interface
There are three antenna ports for SIM808, GSM antenna port named RF_ANT, GPS antenna port named
GPS_ANT, The RF interface of the three antenna ports has an impedance of 50Ω.The maximum gain of the
antenna gain should not exceed 3dbi considering the SAR radio.
 The input impendence of the antenna should be 50Ω, and the VSWR should be less than 2.
 It is recommended that the GSM antenna and the GPS antenna be placed as far as better.
 The isolations of the three antenna should be bigger than 30db
5.1 GSM Antenna Interface
There is a GSM antenna pad named RF_ANT for SIM808 the connection of the antenna must be decoupled