Seiwa Si-Tex Vector 3D GPS - Manual (Page 6)

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Chapter 2: Installation
Mounting Location
This section provides information on determining the best location for the 3D.
Note: Mounting Template available -Vector 3D Satellite Compass part number 29030054
GPS Reception
When considering where to mount the 3D, consider the following GPS reception recommendations:
• Consider GPS (and hence SBAS) reception, ensuring there is a clear view of the sky available to
the 3D so the GPS and SBAS satellites are not masked by obstructions that may reduce system
performance
• Since the 3D computes a position based on the internal primary GPS antenna element, mount the
3D where you desire a position with respect to the primary GPS antenna (located on the end
opposite the recessed arrow on the underside of the enclosure)
• Locate any transmitting antennas away from the 3D by at least a several feet to ensure tracking
performance is not compromised, giving you the best performance possible
• Make sure there is enough cable length to route into the vessel to reach a breakout box or terminal
strip
• Do not locate the antenna where environmental conditions exceed those specified in Table B-5 on
page 54
3D Environmental Considerations
The 3D is designed to withstand harsh environmental conditions; however, adhere to the following limits
when storing and using the 3D:
•
Operating temperature: -30°C to +70°C (-22°F to +158°F)
• Storage temperature: -40°C to +85°C (-40°F to +185°F)
• Humidity: 100% non-condensing
VHF Interference
VHF interference from such devices as cellular phones and radio transmitters may interfere with GPS
operation. Keep the following in mind regarding VHF interference:
•
VHF marine radio working frequency (Channel 1 to 28) is from 156.05 to 157.40 MHz. The L1
GPS working center frequency is 1575.42 MHz. The bandwidth is +/- 2MHz to +/- 10 MHz, which
is dependent on the GPS antenna and receiver design.
• VHF marine radios emit strong harmonics. The 10th harmonic of VHF radio, in some channels,
falls into the GPS working frequency band, which may cause the SNR of GPS to degrade
significantly.
• The radiated harmonic signal strength of different brands/ models varies.