ashtech DG14, Reference Manual

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14 DG14 and DG16 Board & Sensor Reference Manual
RF Connections
A 50-Ohm coaxial cable connects the GPS/Beacon antenna (with integrated
LNA) to the DG16 RF connector and the GPS antenna. No separate cable is
required to receive WAAS, EGNOS, MSAS, or Beacon signals. The DG16 can
supply power to the LNA through the cable. All signals are received through the
RF input.
The DG16 board’s RF connector is a standard SMA female connector (TNC on
the DG16 Sensor, see Figure 1.7) or an optional OSX (MCX) RF connector. The
SMA connector shell is connected to common ground on the DG16 board. The
SMA center pin pr4.8 VDC (to power the LNA) and accepts 1575 MHz
RF input from the antenna; the RF and DC signals share the same path. The gain
of the antenna LNA minus the loss of the cable is in between 20 and 30 dB.
Hardware Options
The DG16 has several options:
• The DG14 Board has GPS, WAAS, EGNOS, and MSAS functionality
• The DG14 Sensor has GPS, WAAS, EGNOS, and MSAS functionality
• The DG14 GPS+Beacon Board has GPS and Beacon functionality
• The DG14 GPS+Beacon Sensor GPS and Beacon functionality
• The DG16 Board has GPS, WAAS, EGNOS, MSAS, and Beacon
functionality
• The DG16 Sensor has GPS, WAAS, EGNOS, MSAS, and Beacon
functionality
• The DG16 Development kit has all options loaded
The Altitude Limits Removed [A] and the Velocity Limits Removed [V] options require an export
license.
For simplicity, this manual uses DG16 in reference to all three configurations. Any
deviations from the standard operation will be discussed as necessary.
CAUTION
The DG16 may be damaged if the RF connector center pin is not
isolated from the DC ground. Use a DC block between the center pin
and ground with the following characteristics:
• VSWR 1.15 maximum at 1575 MHz
• Insertion loss 0.2 dB maximum
• Maximum Voltage 5 VDC