ZED-F9H - Integration manual
The antenna supervisor can be configured through the CFG-HW-ANT_* configuration items. The
current configuration of the active antenna supervisor can also be checked by polling the related
CFG-HW_ANT_* configuration items.
The current active antenna status can be determined by polling the UBX-MON-RF message. If an
antenna is connected, the initial state after power-up is “Active Antenna OK" in the UBX-MON-RF
message in the u-center "Message View".
An active antenna supervisor circuit is connected to the ANT_DET, ANT_OFF, ANT_SHORT_N
pins. For an example the open circuit detection circuit using ANT_DET, "high" = Antenna detected
(antenna consumes current); "low" = Antenna not detected (no current drawn).
The following schematic details the required circuit and the sections following it explain how to
enable and monitor each feature:
Figure 21: ZED-F9H antenna supervisor
The bias-t inductor must be chosen for multi-band operation; a value of 47 nH ±5% is
required for our recommended Murata part, with the current limited below its 300 mA
rating. See
section for additional information.
Circuit shows buffer [U4]. Buffer is not strictly necessary when supplied from VCC. It is only
required when supplying antenna voltage that is not obtained from or controlled by module
VCC or VCC_RF .
Part
Recommendation
Comment
L1
Murata LQG15HS47NJ02/47N
300mA and >500 Ω at L band frequencies
C2
Murata GRM033R71C103KE14
CAP CER X7R 0402 10N 10% 16V
TYCO, 0.25PF, PESD0402-140 -55/+125C
ESD protection diode on RF trace
Table 20: Recommended components for antenna supervisor
3.8.1 Antenna voltage control - ANT_OFF
Antenna status (as reported in UBX-MON-RF and UBX-INF-NOTICE messages) is not
reported unless the antenna voltage control has been enabled.
UBX-19030120 - R04
3 Receiver functionality
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