ashtech GG Surveyor, Reference Manual

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Equipment 11
Equipm
ent
RF Interface Connector
The RF connector is a standard TNC female receptacle wired for connection via 50-
ohm coaxial cabling to a GPS antenna with internal LNA. The TNC connector shell is
connected to the ground. The TNC center pin pr4.8 VDC (to power the LNA)
and accepts RF input from the antenna; the RF and DC voltage share the same path.
The RF circuitry receives satellite data from a GPS+GLONASS antenna and LNA via
a coaxial cable, and can supply power to the antenna/LNA by means of that cable. No
separate antenna power cable is required. The LNA power consumption is usually
below 150 milliwatts (depends upon model and manufacturer).
Serial/Power Cable
The serial/power cable (Figure 2.3) connect the GG Surveyor to the power source, the
PC or handheld unit and any peripherals.
CAUTION
The unit may be damaged if the TNC center pin is not isolated from DC
ground.
Figure 2.3: Serial/Power Cable