Installation and Set Up Chapter 3OEM4 Family Installation and Operation User Manual Rev 12 293.1.2 Choosing a Coaxial CableAn appropriate coaxial cable is one that is matched to the impedance of the antenna and receiver beingused (50 ohms), and whose line loss does not exceed 10.0 dB. If the limit is exceeded, excessivesignal degradation will occur and the receiver may not be able to meet its performance specifications.NovAtel offers a variety of coaxial cables to meet your GPS antenna interconnection requirements,including:• 5, 15, or 30 m antenna cables with TNC male connectors on both ends (NovAtel partnumbers C006, C016 and C032 respectively)• 22 cm interconnect adapter cable with MMCX male and TNC female connectors (NovAtelpart number GPS-C002)Note that a conversion is required between the female MMCX connector on the OEM4-G2L andOEM4-G2 GPSCards, and the female TNC connector on Novatel’s GPS antennas.Your local NovAtel dealer can advise you about your specific configuration. Should your applicationrequire the use of cable longer than 30 m you will find the application note RF Equipment Selectionand Installation at our website, www.novatel.com, or you may obtain it from NovAtel CustomerService directly.High-quality coaxial cables should be used because a mismatch in impedance, possible with lowerquality cable, produces reflections in the cable that increase signal loss. Though it is possible to useother high-quality antenna cables, the performance specifications of the OEM4 family receivers arewarranted only when used with NovAtel-supplied accessories.3.1.3 Power Supply RequirementsThis section contains information on the requirements for the input power to the receiver. SeeAppendix A, Technical Specifications starting on Page 109 for more power supply specifications.WARNING: If the voltage supplied is below the minimum specification, the receiver willsuspend operation. If the voltage supplied is above the maximumspecification, the receiver may be permanently damaged, voiding yourwarranty.3.1.3.1 GPSCardsThe OEM4-G2 GPSCard contains a DC to DC converter that is very tolerant to noise and ripple at itsinput. A tightly regulated input supply to the card is not required, as long as it falls within the giveninput range. A tightly regulated input supply to the OEM4-G2L GPSCard is required. The powersupply used for any GPSCard should be capable of 5 W. The voltage input range for each GPSCardtype is given in the table below.Table 4: Voltage Input Ranges for GPSCardsGPSCard Power Input RangeOEM4-G2L +3.3 ± 0.15 VDCOEM4-G2 +4.5 to +18 VDC
