Simrad HS70, User Manual

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Installation | HS70 User Manual
Installation
Mounting Location
This section provides information on determining the best location for the HS70.
GPS Reception
When considering where to mount the HS70, consider the following GPS reception
recommendations:
•
Consider GPS (and hence SBAS) reception, ensuring there is a clear view of the sky available
to the HS70 so the GPS and SBAS satellites are not masked by obstructions that may reduce
system performance
•
Since the HS70 computes a position based on the internal primary GPS antenna element,
mount the HS70 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 HS70 (refer illustration below) 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,
terminal strip or NMEA 2000 T-connector
•
Do not locate the antenna where environmental conditions exceed those specified in
“Specifications” on page 12.
VHF Interference
VHF interference from such devices as cellular phones and radio transmitters may interfere
with GPS operation. For example, if installing the HS70 near marine radios consider the
following:
•
VHF marine radio working frequencies (Channels 1 to 28 and 84 to 88) range from 156.05 to
157.40 MHz. The L1 GPS working center frequency is 1575.42 MHz. The bandwidth is +/- 2 MHz
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
•
Follow VHF radio manufacturers’ recommendations on how to mount their radios and what
devices to keep a safe distance away
•
Handheld 5 W VHF radios may not provide suitable filtering and may interfere with the HS70’s
operation if too close
Ensure there are no nearby devices that may cause VHF interference. Use minimum distances
from nearby VHF antenna as shown on the illustration.
Mounting Orientation
The HS70 outputs heading, pitch, and roll readings. However, the relation of the antennas
to the boat’s axis determines whether you will need to enter a heading offset. The primary
antenna is used for positioning and the primary and secondary antennas, working in
conjunction, output heading, pitch, and roll values.
Mount the HS70 parallel to, and along the centerline of, the axis of the boat. This provides a
true heading. In this orientation:
•
You can enter a heading offset in a Simrad compatible head unit (AP24, AP28, AP70, AP80, IS20
Graphic/Combi, NSE, NSO, NSS) to calibrate the physical heading to the true heading of the
vessel
•
You will have an offset in the pitch/roll output if the unit is not installed in a horizontal plane
The figure shows recommended orientation and resulting signs of heading (H), pitch (P) and
roll (R) values.
1.5 m (4.9 ft
radius
at top
1.0 m (3.3 ft)
radius
at base
+H
+R
-R
-H
-P
+P
P
S
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