Installation manual
Table Of Contents
- Front page
- Title page
- Table of contents (interactive)
- About this manual
- Simrad SH90
- Getting started
- Operational procedures
- Power on/off procedures
- Menu procedures
- Gain adjustment procedures
- Mode procedures
- Markers and symbols procedures
- Storage procedures
- Automatic search and tracking procedures
- User setting procedures
- Installation of options
- Software procedures
- Display modes
- Operating Panel
- Menu descriptions
- Parameters
- About the parameter dialogs
- Alphabetical list of parameters
- Parameter descriptions
- About
- AGC
- Beam
- Bearing (Display)
- Bearing (Horizontal)
- Bearing (Vertical)
- Colour Threshold
- Colours
- Data Source
- Date and time properties
- Dead Reckoning
- Default Setting
- Density
- Direction Indicator
- Display Gain
- Edit Gear (Purse)
- Edit Gear (Trawl)
- Edit School
- External Synchronisation
- Fish Alarm
- Gain
- Gear
- Heading
- Inspect Object
- Language
- Menu
- Message Bar
- Middle Pos(ition)
- Mode
- Mode Buttons
- Movements
- Noise Filter
- Palette
- Panel Backlight
- PP Filter
- Pulse Form
- Range
- Range (CatchView)
- RCG
- Recall
- Recall Mode
- Ruler
- Scale
- School Data
- Scientific Output
- Search Sector
- Search Step
- Slant Range
- Speed
- Stabilizer
- Status
- Store
- Store Mode
- Target Track
- Tilt
- Tip
- Track History
- Track Window
- Transducer
- TRU On/Off
- True Range
- TVG
- TX Power
- Units
- User Setting
- Wind Direction
- Zoom
- Zoom Scale
- Basic theory
- On-board maintenance
- Preventive maintenance schedule
- Wheelhouse units on-board maintenance
- Transceiver Unit on-board maintenance
- Power Supply Unit maintenance
- Hull Unit maintenance
- Index (interactive)
SimradSH90
BASICTHEORY
Thischapterexplainssomeofthebasictheoryrelatedtosettings,
errorsourcesandnoiseconditions.
Topics
•Settingsonpage178
•Noiseandreverberationonpage182
•Layersanddeectionsonpage185
Settings
Asonarwilltransmitasoundwaveintothewateraroundthe
vessel.Whenthissoundwavehitssh,bottom,orotherobjects
inthewater,apartofthesoundwillbereturnedasechoes.
Theseechoesarecollectedbythesonar,interpretedbythesonar
computers,andpresentedonthedisplay.
Themostimportantinterpretationishoweverlefttoyou,and
itmayoftenbedifculttodistinguishtheechoesandidentify
targets.Inordertohelpyouwiththis,theSH90sonarprovides
numerousadvancedlterandgainfunctions.Youcanalsotilt
thesonarbeamverticallyinordertoachieveanoptimumresult,
andyoucanusetheverticalslicetoview“across”intothewater.
Thischapterprovidesyouwithsomebasictheoryaboutsome
ofthekeysettingsavailable.
WhatisTVG?
TVGmeansTimeVariedGain.Asechoeswillbeweaker
whenthedistancetothemincrease,thesonarwillautomatically
amplifydistantechoesmorethancloseechoes.Inpractice,the
gainwillincreaseinproportionwithhowlongthesonarmust
waitfortheechoes.
Figure39TheTVGprinciple:Thegainattime(B)islargerthanattime(A)
A
(CD015005-003)
0
1
10 100
1000
B
C
178
323775/B