VLF RECEIVER ANTENNA DESIGN FREE

In the present scenario there has not been a system Systems are used by USA and Russia as the primary means of communication Previously fixed site very low frequency transmit antenna System especially used for this antenna (15-30 kHz) is enormous The combined skill of radio, civil and mechanical engineers. Is a specialized field of engineering and it is only possible to have To design the Very Low Frequency (VLF) transmitting antenna design Is a more fundamental quality since it is independent of the medium. The velocity u which depends on the medium. Thus in the above-mentioned parameters, the wavelength depends on The wavelength l of a wave is related to the frequency f and Long infrared waves overlap into a twilight zone that may be regarded as Of the antenna is in fractions of a millimeter. Thousands of meters, whereas the extreme high frequency range the size TheД®xtreme lowest frequency the size of the antenna in length from Penetrate sea water to depths less than the ELF waves while maintainingДЄntenna is a device which is used to transmit or receive theД¬ontinuous wave energy radiated oscillates at radio frequencies. Very low frequency (VLF) band at frequencies of about 20,000 Hertz (Hz) Type of small ELF antenna which used in both ways. With feasible sea condition but it is very difficult to construct such Transmission, the deeper into the ocean a useable signal will travel This means that the lower the frequency a radio Waves (electromagnetic waves) from sea water increases with theДЇrequency of the signal.

Which make use of a principle in physics where the attenuation of radio Reliable and safety communication is the ELF communications systems Periscope depth to use these radio communication systems. The only and major disadvantage is the submarine to come upto the Most reliable means of communications between submarines and otherДЇorces/command structure is with various radio systems. Sound transmission, the amount of data/information that can beД¬ommunicated through sonic means is severely limited.ДЄfter realizing sonic limitation it is conclude that theprimary and The physical characteristics of the sea of underwater Water, machinery, screws, etc., can reduce the range to less than half Severe reverberationД®ffects and local noise, caused by ship's movement through the Kilometers greater than that achieved by ships. Operating in a sound channel, the communication range may be many Submarine canДЄchieve the range more than out to 12,000 meters if the submarines are Propagation and the range and quality of transmission varies with waterД¬onditions, local noise level, and reverberation effects. In this condition the sea water is the medium for radio wave Or tone/sound signal generation, utilizing sonar or sonobuoy type

Very useful for the submarine to be signaled the attack accuracy by ExerciseД¬an be started and stopped, or one in progress can be modified. The ship can be so informed if any emergency onboard submarine. In the normal practice and especially duringД®xercise the ships can advise the submarine when it is safe to surface. In the submarine the paramount importance is the safety of Submarines are totally blind when they are submerged and in someД¬ases it is necessary for the ships to communicate with submerged Keywords: VLF antenna, propagation in sea water, radio waves This is an experimental effort to enquire the live dataДЄnd with the passage of time and effort it can be used for both way To surface to receive more information via other means but in this paperДЄ view is given to the readers the both way communication under water Previously it was a one-way, non-voice system,Д«ut it provides sufficient information to the submarine's commander Speed of transmission of other systems, it 'gets through' It's really a backup of existing, higher-frequency, Penetrate sea water down to a depth of roughly 20 meters. Was analyzed by the scientists that VLF radio waves (3-30 KHz) can In case of nuclear-powered submarines it is veryДifficult to come on surface for communication.

Is to surface and raise an antenna above the water surface to use In the ocean salts water provide a hindrance forД®lectromagnetic radiation such as normal radio communication because sat Techniques and devices which gives totally different criteria asД¬ompared to the air. Waheed-uz-Zaman - E-mail: andД¬ommunication with submerged submarines requires specific

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VLF RECEIVER ANTENNA DESIGN FREE

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Vlf receiver antenna design