APN-077: RF Equipment Selection and Installation for OEM7

NovAtel offers GNSS antennas and cables tailored for use with NovAtel GNSS receivers. These accessories provide for both easy installation and optimal operation. However, as the receivers are designed to meet the needs of a wide range of applications, the use of non-NovAtel accessories for a unique installation may be desired. This application note provides information on the standard NovAtel configuration, as well as recommendations for meeting the receiver’s RF input requirements in special cases. In addition, information on obtaining the equipment required for such cases is provided.

A variety of symbols are used in this application note to depict equipment configurations and characteristics. The meaning of each symbol is given below.

Symbol Legend

Symbol	Description
	A connection between two pieces of equipment, either directly or through an adapter.
	Circuitry that blocks DC power, but allows RF signals to pass.
	Circuitry that allows DC power to pass, but blocks RF signals.
	Current-limiting circuitry, such as a fuse.

Receiver Input Gain Requirements

The RF input gain supported by NovAtel's OEM7 GNSS receiver depends on the firmware version running on the receiver.

Receiver Firmware Version	Supported RF Input Gain
OEM7.03 or earlier	+15 dB to +40 dB
OEM7.04 or later	+15 dB to +55 dB

For optimum GNSS tracking and TerraStar L-Band reception, a cascaded antenna gain of +25 dB to +35 dB is recommended.

If HDR Mode is enabled through the Interference Toolkit, the minimum RF input gain is +20 dB.

NovAtel sells a variety of RF cables ranging in length from 8.5 cm to 30 metres. The following table shows the typical signal power loss of these RF cables in dB.

NovAtel RF Cable Loss Figures

RF Cable Part Number	L1 (1575.42 MHz)	L2 (1227.60 MHz)
01017278 8.5 cm MMCX to TNC	-0.29 dB	-0.28 dB
GPS-C006 5 m TNC to TNC	-3.28 dB	-2.85 dB
GPS-C016 15 m TNC to TNC	-10.2 dB	-8.80 dB
GPS-C032 30 m plus TNC pigtail cables	-11.3 dB	-10.3 dB