| Autopilots The first self-steering gear
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| | around the globe, they are positioned in
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| was introduced in the 1920's to control
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| | such a way that at any place on the
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| model yachts but it was not until 1948
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| | earth's surface a direct line of sight
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| that the principle was applied to full
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| | can be established to a minimum of 4
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| scale yachts. Standing at the helm for
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| | satellites. A fix is obtained by
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| lengthy periods, monitoring instruments
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| | measuring accurately the distance between
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| and keeping a good look out can be very
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| | a satellite and the GPS receiver at a
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| tiring. An autopilot relieves the
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| | precise time. Because the exact position
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| helmsman from steering the correct course
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| | of the satellite is known, these
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| leaving him free to maintain a proper
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| | distances provide position lines which
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| watch. The autopilot can be set to either
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| | are converted by a microprocessor within
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| steer a compass course or a course
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| | the GPS receiver to read outs of latitude
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| relative to the wind. A fluxgate compass
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| | and longitude.The log is used to measure
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| or electronic wind indicator feeds
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| | the boats speed through the water. A
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| information to a microprocessor which
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| | paddle wheel or impeller, mounted below
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| then makes the necessary rudder movements
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| | the waterline is turned by the flow of
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| to return the vessel to it's required
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| | water, this generates electrical impulses
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| course. The mechanical power is applied
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| | that are fed to a microprocessor that
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| to the rudder by either electric linear
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| | displays both speed and distance
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| activators, hydraulic pumps or rotary
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| | run.Inverters - On most boats today you
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| drives. GPS/Chart plotters can be used to
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| | will find domestic equipment of one sort
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| input navigational instructions to the
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| | or another. For on board entertainment
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| autopilot.Battery Chargers will keep
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| | there are televisions and stereo systems.
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| batteries fully charged thereby extending
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| | With the popularity of chart plotters
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| their working life.Chart Plotters
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| | comes the PC or laptop. Maintenance often
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| Typically a chart plotter consists of an
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| | requires the use of power tools.
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| antenna, mounted high on the boat, to
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| | Liveaboards might have a washing machine,
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| track GPS signals and a display unit
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| | dishwasher or microwave. Can take 12v,
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| sited either at the at the navigation
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| | 24v or 48v supply and convert it to a
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| station or the helm of the vessel. The
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| | stable 110 v or 220v AC supply.Navtex can
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| vessels position is sent from the antenna
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| | perhaps best be described as a
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| to the display unit which in turn shows
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| | continuously updated telex service
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| it graphically on the chart. The Chart
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| | providing navigation and weather
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| itself will look similar to it's paper
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| | information within specified areas. An on
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| equivalent and show depth, land mass,
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| | board receiver, tuned to 518kHz, the
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| navigational aids such as bouys and
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| | worldwide Navtex frequency, if left
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| potential dangers in the form of wrecks
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| | turned on will either print out or
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| and obstructions. The user can add way
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| | display the latest massages sent from a
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| points to the chart and zoom in and out
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| | local station. The service is available
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| of the display. Chart plotters can be
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| | up to 400 miles from the coast.Radar
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| connected to drive an autopilot and/or
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| | enables you to see what otherwise would
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| send GPS data to a fish finder or radar.
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| | be invisible. They offer greatest benefit
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| They can also interface with a laptop
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| | at night and in fog or rain and are of
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| enabling complex passage planning to be
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| | particular value when close to shore or
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| done away from the boat and then entered
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| | in busy shipping lanes. They consist of
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| into the chart plotter after arriving at
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| | an antenna and a display. The antenna
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| the boat.Magnetic Transmitting Compasses
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| | sends out a stream of RF energy which is
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| work like traditional compasses using
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| | reflected back off hard objects. When
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| magnets to determine the vessels
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| | this energy is bounced back it is
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| orientation to the earth's magnetic field
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| | converted to a signal which displayed to
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| they then transmit the boats heading to
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| | the user. The antenna rotates every few
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| an electronic display. They make steering
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| | seconds, the display continuously
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| easier than with conventional compasses
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| | calculates the direction of the antenna
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| because they display steadier headings
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| | and so a precise bearing to the target is
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| and do not suffer from the "lag" that
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| | calculated. The time is measured for the
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| occurs when making a turn. They can
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| | energy to be reflected and so the
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| interface with chart plotters, autopilots
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| | distance of the target is also
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| and radar. Fluxgate Compasses consist of
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| | displayed.Satellite Phones consist of an
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| two pieces of readily saturated magnetic
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| | antenna, a modem and a normal handset.
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| material with coils wound round them in
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| | They are powered by an iridium battery.
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| opposing directions. AC current is passed
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| | Their range is anywhere covered by in
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| through the coils and the material is
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| | Inmarsat Mini-M satellite. Voice, fax,
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| saturated in one direction and then the
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| | email and data can be
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| other. The earth's magnetic field affects
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| | transmitted.Satellite TV requires an
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| slightly the time at which saturation
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| | antenna and of course a television.
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| occurs, earlier in one coil and later in
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| | Reception is available within a
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| the other. The difference is then
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| | "footprint" which is based on EIRP
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| calculated giving an output proportional
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| | (Effective Isotropic Radiated Power) of a
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| to the earth's magnetic field. They are
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| | transmitting satellite. The EUTELSAT
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| accurate to 0.1 of a degree. Their output
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| | together with the two ASTRA satellites
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| can be displayed digitally to the
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| | cover Europe. NILESAT and the two
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| helmsman or they can interface with
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| | ARABSATs cover Africa and the Middle
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| autopilots, chart plotters and radar.Echo
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| | East. Good coverage is also available in
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| Sounders work on the same principle as
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| | North, Central and Southern America.SSB
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| sonar. A transducer emits a narrow beam
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| | Radio has a range of several thousand
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| of high frequency sound. This is
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| | miles. You will need an FFC license, or
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| reflected by any solid objects and the
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| | the equivalent in whichever country you
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| time between transmission and receipt of
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| | plan to operate it. Power consumption is
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| the echo is measured. The speed of sound
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| | a consideration. Up to 100 Watts may be
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| through water is know and so the range or
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| | required for transmission. SSB radio
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| distance to the sea bed can be
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| | requires several items of equipment. A
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| calculated. That is then displayed in
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| | transceiver capable of SSB operation, An
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| metres. Forward Looking Sonar (FLS)
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| | antenna, this must be 8 metres long and
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| enables you to see the underwater hazards
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| | in practice most boats use a backstay or
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| before you're actually on top of them. A
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| | shroud for the purpose having fitted the
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| typical range for a FLS is 150 metres.An
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| | necessary insulators. An antenna tuner
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| Emergency Position Indicating Radio
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| | matched to the transceiver model. If you
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| Beacon (EPIRB) is a piece of equipment
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| | want to send email you will also need and
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| designed to float free of a vessel in
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| | radio modem and computer.VHF Radio The
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| distress. It then sends a radio signal
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| | power required to transmit is minimal,
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| that can be detected by Search and Rescue
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| | all sets have the option of transmitting
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| Satellite Aided Tracking (SARSAT)
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| | on either 1 Watt or 25 Watts and the
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| satellites. They relay a message to a
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| | lower power should be used whenever
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| ground station that in turn can instigate
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| | possible. Unlike telephones that allow
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| a search and rescue operation.Fish
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| | you to both talk and hear at the same
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| Finders use the same technology as sonar.
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| | time most VHF sets require you to press a
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| A narrow beam of high frequency sound is
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| | transmit button prior to talking. This is
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| transmitted by a transducer, this is
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| | known as simplex. Duplex sets are
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| reflected by solid objects such as the
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| | available but are much more expensive.
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| sea bed. By developing this technology
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| | VHF radio waves travel in straight lines
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| fishfinders provide displays that show
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| | so the aerial should be mounted as high
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| where the fish are and they can
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| | as possible, preferably at the
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| differentiate between bait fish and
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| | masthead.Ken Jones runs a Sailing Site.
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| larger speciesGlobal Positioning System
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| | More information about marine
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| (GPS Receivers) - This system was
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| | electronics can be found here
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| originally designed for military purposes
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| | To find manufacturers or suppliers of
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| and is owned and operated by the United
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| | marine electronics in your area visit the
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| States Department of Defence. 24
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| | Marine Directory.
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| satellites are arranged in a "birdcage"
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