ship’s antennas

Ship’s AntennasShip’s Antennas

Ship’s Antenna Ship’s Antenna ArrangementArrangement

Consist of different transmitter and Consist of different transmitter and receiver antennasreceiver antennas


RDF loop

RadarScanner

VHF TX/RX

Navtex RXLoran RX

VHF DSC TX

MF/HF Radio TelephoneVHF T/RX no. 2

DSC RX

E.B. Saturn 35 Radome

VHF DSC RXWatch keeping RX

Radio Wavelengths and Radio Wavelengths and FrequenciesFrequencies

Propagation Speed of Radio waves is Propagation Speed of Radio waves is equal to the speed of light.equal to the speed of light.

Aproximately 300,000 km/secAproximately 300,000 km/secOr 300,000,000 meters/secOr 300,000,000 meters/sec

FormulaFormulaC = f x LambdaC = f x Lambda

C = Propagation speed of radio C = Propagation speed of radio waves(Speed of light)waves(Speed of light)

f = Frequency = Period of cycle. The f = Frequency = Period of cycle. The time it takes for a wave to move time it takes for a wave to move from zero to 360 degreesfrom zero to 360 degrees

Lambda = Wavelength = the distance Lambda = Wavelength = the distance from one wave top to another.from one wave top to another.

Lambda = Wavelength = the distance Lambda = Wavelength = the distance from one wave top to another.from one wave top to another.

f = Period of cycle. The time it takes f = Period of cycle. The time it takes for a wave to move from zero to for a wave to move from zero to 360 degrees360 degrees

Unit of MeasurementUnit of Measurement

HertzHertz

HzHzOr

The Unit used for measuring frequency is HERTZ, Symbolized by Hz

Example 1Example 11 THz (Terra Hz) = 1,000,000,000,000 1 THz (Terra Hz) = 1,000,000,000,000

HzHz1 GHz (Giga Hz) = 1,000,000,000 Hz1 GHz (Giga Hz) = 1,000,000,000 Hz1 MHz (Mega Hz) = 1,000,000 Hz1 MHz (Mega Hz) = 1,000,000 Hz1 KHz (Kilo Hz) = 1,000 Hz1 KHz (Kilo Hz) = 1,000 Hz

Example 2Example 2Ch 70 Ch 70

= = 156.525 MHz 156.525 MHz

= = 156,525 KHz 156,525 KHz

= = 156,525,000 Hz156,525,000 Hz

Example 3Example 3Convert 125 MHz to kHzConvert 125 MHz to kHz

==

125 000 kHz125 000 kHz==

125 000 000 Hz125 000 000 Hz

Example 4Example 4Convert 12.5 MHz to HzConvert 12.5 MHz to Hz

==

12 500 kHz12 500 kHz==

12 500 000 Hz12 500 000 Hz

Find the wavelength for VHF Find the wavelength for VHF ch. 70 (156.525 Mhz)ch. 70 (156.525 Mhz)

L = L = CC f f

L = L = 300,000,000 m/sec.300,000,000 m/sec.156,525,000 Hz156,525,000 Hz

L = 1.92 metersL = 1.92 meters

Find the frequency if Find the frequency if wavelength is 600 meters.wavelength is 600 meters.

f = f = CC L L

f = f = 300,000,000 m/sec.300,000,000 m/sec.600 m.600 m.

f = 500,000 Hzf = 500,000 Hz

Find the wavelength for 2182 Find the wavelength for 2182 kHzkHz

L = L = CC f f

L = L = 300,000,000 m/sec.300,000,000 m/sec.2,182,000 Hz2,182,000 Hz

L = 137.49 mL = 137.49 m

ELFELF 3 Hz – 2 KHz3 Hz – 2 KHz 100000 km – 100 100000 km – 100 kmkm

VLFVLF 3 KHz – 30 KHz3 KHz – 30 KHz 100 km – 10 km100 km – 10 kmLFLF 30 KHz – 300 KHz30 KHz – 300 KHz 10 km – 1 km10 km – 1 kmMFMF 300 KHz – 3 MHz300 KHz – 3 MHz 1 km – 100 m1 km – 100 mHFHF 3 MHz – 30 MHz3 MHz – 30 MHz 100 m – 10 m100 m – 10 mVHFVHF 30 MHz – 300 30 MHz – 300

MHzMHz10 m – 1 m10 m – 1 m

UHFUHF 300 MHz – 3 GHz300 MHz – 3 GHz 1 m – 10 cm1 m – 10 cmSHFSHF 3 GHz – 30 GHz3 GHz – 30 GHz 10 cm – 1 cm10 cm – 1 cmEHFEHF 30 GHz – 300 30 GHz – 300

GHzGHz1 cm – 1 mm1 cm – 1 mm

Table of WavelengthsTable of Wavelengths

F2-layer

Day

D-layer

Night

F1-layerE-layer

TX RXDirect Wave

Reflected Wave

VHFVHF

TX RX

Reflected Wave

Ground Wave

MFMF

TX

HFHF

8 Mhz 16 Mhz

TX

E- Layer’s EffectE- Layer’s Effect

E - Layer

F - Layer

DAY

TX


E - Layer

F - Layer

NIGHT

TX


E - Layer

F - Layer