GP1670F_1870F Operator's Manual - Furuno USA

13. INSTALLATION13.2 Installation of Antenna UnitMounting considerationsThe antenna unit GPA-017/017S (option) is available for receiving GPS signal with farthersensitivity.Select a suitable mounting location considering the following:• Select a location out of the radar beam. The radar beam will obstruct or prevent receptionof the GPS satellite signal.• The location should be well away from a VHF antenna. A GPS receiver is interferedby a harmonic wave of a VHF antenna.• There should be no interfering object within the line-of-sight to the satellites. Objectswithin line-of-sight to a satellite, for example, a mast, may block reception or prolongacquisition time.• Mount the antenna unit as high as possible. Mounting the antenna unit as high aspossible keeps it free of interfering objects and water spray, which can interrupt receptionof GPS satellite signal if the water freezes.• If the antenna cable is to be passed through a hole which is not large enough topass the connector, you may unfasten the connector with a needle nose pliers and3/8-inch open-end wrench. Refasten it as shown below after running the cablethrough the hole.WasherClamp nutGasket (reddish brown)ShieldCenter pin (soldered)Connector shell• If the internal GPS antenna is used, be sure there are no obstructions above oraround the display unit.13.3 Installation or Transducers13.3.1 How to mount a transducer through the hullTransducer mounting locationThe thru-hull mount transducer provides the best performance of all, since the transducerprotrudes from the hull and the effect of air bubbles and turbulence near the hullskin is reduced. If your boat has a keel, the transducer should be at least 30 cm awayfrom it.The performance of this fish finder is directly related to the mounting location of thetransducer, especially for high-speed cruising. The installation should be planned inadvance, keeping the length of the transducer cable and the following factors in mind:• Air bubbles and turbulence caused by movement of the boat seriously degrade thesounding capability of the transducer. The transducer should, therefore, be located13-2