{"id":14516,"date":"2025-06-07T16:29:13","date_gmt":"2025-06-07T10:59:13","guid":{"rendered":"https:\/\/ibexaviation.com\/pilot-training\/?p=14516"},"modified":"2025-07-20T07:30:01","modified_gmt":"2025-07-20T02:00:01","slug":"radio-antenna","status":"publish","type":"post","link":"https:\/\/ibexaviation.com\/pilot-training\/radio-antenna\/","title":{"rendered":"Radio Antenna"},"content":{"rendered":"\n<h2>Antenna<\/h2>\n\n\n\n<h3>Transmitter and Receiver Antenna<\/h3>\n\n\n\n<ul><li>Antennas are used to transmit and receive the radio waves<\/li><li>Antenna or Ariels should be made of good conductors like aluminium<\/li><li>Transmitters transmit modulated wave which are demodulated in the receiver to extract intelligence<\/li><\/ul>\n\n\n\n<h3>Length of Antenna<\/h3>\n\n\n\n<ul><li>Ideal length of an antenna has to be proportional to the wave length<\/li><li>Since it is difficult to construct antennas in kilometres for lower frequencies we use half or quarer wave dipole antennas<\/li><li>Size of a Half wave dipole antenna is made equal to half the wave length<\/li><li>Folded half wave dipoles are used for televisions in order to receive a broader band of frequencies<\/li><li>Size for quarter wave dipole antenna is a quarter of wavelength<\/li><li>An Ideal quarter wave antenna is called as Marconi antenna with a length of 95% of quarter of wavelength<\/li><li>Marconi antennas are fixed to metal surfaces of aircraft increases antenna size<\/li><li>Ariel Loading Unit enables utilization of the same antenna for a range of signals<\/li><\/ul>\n\n\n\n<h3>Directional Antenna<\/h3>\n\n\n\n<ul><li>Directional antennas help in focusing radio waves in a particular direction<\/li><li>For example, Instrument Landing System transmits waves in the runway direction<\/li><li>Parasitic elements like metallic reflectors with 5% longer length behind the antenna assists in directivity<\/li><li>Distance between ariel and reflector is a quarter of its wavelength<\/li><li>Yagi antenna use additional parasitic elements in front for directivity<\/li><li>Side lobes are unwanted signals transmitted by Yagi antennas in other than the desired direction<\/li><\/ul>\n\n\n\n<h3>Loop Antenna<\/h3>\n\n\n\n<ul><li>Loop antenna is a rotating loop shaped antenna used for direction finding<\/li><li>Rotating loop calculates the phase difference between its vertical elements<\/li><li>Phase difference is zero only when the loop is perpendicular to wave<\/li><li>Error signal is generated due to phase difference other directions inducing a current in the circuit<\/li><li>Automatic Direction Finder utilise loop ariel principle for direction measurement<\/li><\/ul>\n\n\n\n<h3>Radar Systems<\/h3>\n\n\n\n<ul><li>Radio detection and ranging systems are used to detect objects using narrow and directional beams in SHF and EHF bands<\/li><li>A rotating antenna is used in radars to get a 360 deg picture<\/li><li>Radar antennas obtain power through wave guides which are vacuum filled flexible tubes of half wave length<\/li><li>Low levels of resistance in wave guides provide greater power supply to the Radar Transmitter Antenna<\/li><\/ul>\n\n\n\n<h3>Parabolic Radar Antenna<\/h3>\n\n\n\n<ul><li>Radar systems use parabolic dish antenna to produce directional waves<\/li><li>Parabolic reflectors in radars produce parallel waves of equal path length and same phase<\/li><li>Side lobes from parabolic dish may affect the functioning of radar equipment<\/li><\/ul>\n\n\n\n<h3>Flat Plate Radar Antenna<\/h3>\n\n\n\n<ul><li>Flat plate or Slotted planar array antenna are used in Airborne weather radars<\/li><li>Many parallel beams are transmitted through slots in a metal plate producing a narrow beams of high energy<\/li><li>Flat plate antennas have lesser side lobes and require lesser power for transmission<\/li><\/ul>\n\n\n\n<h2>Best of luck<\/h2>\n","protected":false},"excerpt":{"rendered":"<p>Antenna Transmitter and Receiver Antenna Antennas are used to transmit and receive the radio waves Antenna or Ariels should be made of good conductors like aluminium Transmitters transmit modulated wave which are demodulated in the receiver to extract intelligence Length of Antenna Ideal length of an antenna has to be proportional to the wave length Since it is difficult to construct antennas in kilometres for lower frequencies we use half or quarer wave dipole antennas Size of a Half wave dipole antenna is made equal to half the wave length&hellip;<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"disable_featured_image":false},"categories":[326],"tags":[],"_links":{"self":[{"href":"https:\/\/ibexaviation.com\/pilot-training\/wp-json\/wp\/v2\/posts\/14516"}],"collection":[{"href":"https:\/\/ibexaviation.com\/pilot-training\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/ibexaviation.com\/pilot-training\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/ibexaviation.com\/pilot-training\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/ibexaviation.com\/pilot-training\/wp-json\/wp\/v2\/comments?post=14516"}],"version-history":[{"count":0,"href":"https:\/\/ibexaviation.com\/pilot-training\/wp-json\/wp\/v2\/posts\/14516\/revisions"}],"wp:attachment":[{"href":"https:\/\/ibexaviation.com\/pilot-training\/wp-json\/wp\/v2\/media?parent=14516"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/ibexaviation.com\/pilot-training\/wp-json\/wp\/v2\/categories?post=14516"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/ibexaviation.com\/pilot-training\/wp-json\/wp\/v2\/tags?post=14516"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}