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LEON-G100 / LEON-G200 - System Integration Manual
GSM.G1-HW-09002-G3
Preliminary
Design-In
Page 98 of 125
It is recommended to use an antenna with a built-in diagnostic resistor in the range from 5 k
Ω
to 30 k
Ω
to
assure good antenna detection functionality and to avoid a reduction of module RF performances.
For example: consider GSM antennas with built-in DC load resistor of 15 k
Ω
.
Using the +UANTR AT command, the module reports the resistance value evaluated from
ANT
pad to GND:
Reported values close to the used diagnostic resistor nominal value (i.e. values from 10 k
Ω
to 20 k
Ω
if a
15 k
Ω
diagnostic resistor is used) indicate that the antenna is connected
Values above the maximum measurement range limit (about 53 k
Ω
) indicate that the antenna is not
connected
Reported values below the minimum measurement range limit (about 1 k
Ω
) indicate that the antenna is
shorted to GND
Measurement inside the valid measurement range and outside the expected range may indicate an improper
connection, damaged antenna or wrong value of antenna load resistor for diagnostic
Reported value could differ from the real resistance value of the diagnostic resistor mounted inside the
antenna assembly due to antenna cable length, antenna cable capacity and the used measurement method