RCB-F9T - Integration manual
Do not add any series resistance greater than 0.2
Ω
to the VCC supply as it will generate
input voltage noise due to dynamic current conditions.
For the RCB-F9T board the equipment must be supplied by an external limited power source
in compliance with the clause 2.5 of the standard IEC 60950-1.
4.2.2 RCB-F9T VCC_ANT: Antenna power supply
The
VCC_ANT
pin is for active antenna powering and typical voltage level should be 5.0 V.
The RCB-F9T board is having a current limiting circuitry that limits the current to the RF connector
and if too high current consumption is triggered, then over current protection is activated. For this
reason, it is important that the connected active antenna does not consume more current than 100
mA.
VCC_ANT is used only for active antenna powering. If active antenna powering is not
needed, then the VCC_ANT can be left to unconnected.
4.3 Antenna
u-blox recommends using an active antenna with RCB-F9T.
If an active antenna needs to be implemented in an application case, it is recommended that an
OEM active antenna module be used that meets our specification. To implement the required RF
circuitry and source the required components to meet group delay specification is not a simple
process compared to previous L1-only implementation.
Figure 19: u-blox low cost dual-band antenna internal structure
A suitable ground plane is required for the antenna to achieve good performance.
Location of the antenna is critical to reach the stated performance. Unsuitable locations
could include, under vehicle dash, rear-view mirror location, etc.
L1 + L2/E5b active antenna required specifications
Parameter
Specification
Antenna type
Active antenna
Minimum active antenna gain
17 dB
Maximum active antenna gain
50 dB
Active antenna recommendations
Noise figure
<4 dB
L1 band antenna gain
1559 - 1606 MHz: 3 dBic typ.
1
Including passive losses (filters, cables, connectors etc.)
2
Measured with a ground plane d=150 mm
UBX-19003747 - R04
4 Design
Page 44 of 54
Early production information