"निम्न आवृत्ति (LF)": अवतरणों में अंतर

छो Robot: Adding it:Low frequency
छो Bot: अंगराग परिवर्तन
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! [[निम्न आवृत्ति]] (LF)
|-
| साइकिल प्रति सै: 30&nbsp;kHz to 300&nbsp;kHz <br />
तरंगदैर्घ्य: 10&nbsp;km to 1&nbsp;km
|}
 
'''निम्न आवृत्ति''' या '''LF''' वे [[रेडियो आवृत्ति]] होती हैं, जो कि 30&nbsp;kHz&ndash;300&nbsp;kHz के मध्य आती हैं । इसे किलोमीटर पट्टी या तरंग भी कहते हैं । क्योंकि इसका तरंग दैर्घ्य दस से एक किलोमीटर होता है ।
 
== सामरिक प्रयोग ==
== प्रयोग एवं अमेच्योर==
A 2.1&nbsp;kHz allocation, the [[136 kHz]] band (135.7&nbsp;kHz to 137.8&nbsp;kHz), is available to [[amateur radio]] operators in some countries in Europe, New Zealand and French overseas dependencies. The world record distance for a two-way contact is over 10,000&nbsp;km from near [[Vladivostok]] to [[New Zealand]].<ref name="ZLUA0">{{cite web|publisher=The World of LF |url=http://www.wireless.org.uk/newspic92.htm |title=QSO ZL/UA0 on 136 kHz}}</ref> As well as conventional [[Morse code]] many operators use very slow computer controlled Morse code or specialized digital communications modes. A proposal at the WRC-07 [[World Radiocommunication Conference]] aims to make this a worldwide amateur radio allocation.
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In the United States there is a special license free allocation in the longwave range called [[LowFER]]. This experimental allocation between 160&nbsp;kHz and 190&nbsp;kHz is sometimes called the "Lost Band". Unlicensed operation by the public is permitted south of 60 degrees north latitude, except where interference would occur to ten licensed location service stations located along the coasts. Regulations for use include a power output of no more than 1 watt, and an antenna/ground-lead length of no more than 15 meters, and a field strength of no more than 4.9 microvolts/meter. Also, emissions outside of the 160&nbsp;kHz&ndash;190&nbsp;kHz band must be attenuated by at least 20 dB below the level of the unmodulated carrier. Many experimenters in this band are amateur radio operators.
 
== मौसम संबंधी प्रसारण ==
 
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A regular service transmitting [[radioteletype|RTTY]] marine meteorological information on LF is the German Meteorological Service (Deutscher Wetterdienst or [http://www.dwd.de DWD]). The DWD operates station DDH47 on 147.3&nbsp;kHz using standard ITA-2 alphabet with a transmission speed of 50 baud and FSK modulation with 85 Hz shift <ref>{{cite web|url=http://www.dwd.de/de/wir/Geschaeftsfelder/Seeschifffahrt/Sendeplaene/Sendeplaene.htm | title=DWD Sendeplan | accessdate=2008-01-08}}</ref>.
 
== रेडियो नौवहन संकेत ==
 
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== रेडियो प्रसारण ==
 
यह प्रसारण होता है 148.5 से 283.5&nbsp;kHz के मध्य, यूरोप एवं एशिया के भागों में ।
 
== एण्टीना ==
 
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