{"id":2289,"date":"2022-09-23T00:14:17","date_gmt":"2022-09-22T22:14:17","guid":{"rendered":"http:\/\/f6kmf.fr\/?p=2289"},"modified":"2022-09-23T00:14:19","modified_gmt":"2022-09-22T22:14:19","slug":"antenne-si-tu-nas-pas-doseille-essaye-le-trefle","status":"publish","type":"post","link":"https:\/\/f6kmf.fr\/index.php\/2022\/09\/23\/antenne-si-tu-nas-pas-doseille-essaye-le-trefle\/","title":{"rendered":"Antenne\u00a0: si tu n\u2019as pas d\u2019oseille essaye le tr\u00e8fle\u00a0!"},"content":{"rendered":"\n<p style=\"text-align:right\"><strong>Par Gilles F1EFW<\/strong><\/p>\n\n\n\n<p class=\"has-background has-pale-cyan-blue-background-color\">Je cherchais une antenne 435\/438Mhz (Fr\u00e9quence descendante de nombreux satellites) facile \u00e0 r\u00e9aliser, \u00e0 polarisation circulaire et avec un diagramme de rayonnement omnidirectionnel. <br>J&rsquo;ai trouv\u00e9 des descriptions de l&rsquo;antenne tr\u00e8fle (cloverleaf en Anglais) qui semble adapt\u00e9e \u00e0 cet usage, comme il n&rsquo;y avait pas d&rsquo;exemple en fran\u00e7ais, je me suis lanc\u00e9 dans l\u2019exp\u00e9rimentation.  <\/p>\n\n\n\n<p class=\"has-background has-very-light-gray-background-color\">L\u2019antenne est compos\u00e9e de 4 \u00ab&nbsp;p\u00e9tales&nbsp;\u00bb  identiques. <\/p>\n\n\n\n<figure class=\"wp-block-image\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"576\" src=\"https:\/\/f6kmf.fr\/wp-content\/uploads\/2022\/09\/IMG_20220920_184846-1024x576.jpg\" alt=\"\" class=\"wp-image-2292\" srcset=\"https:\/\/f6kmf.fr\/wp-content\/uploads\/2022\/09\/IMG_20220920_184846-1024x576.jpg 1024w, https:\/\/f6kmf.fr\/wp-content\/uploads\/2022\/09\/IMG_20220920_184846-300x169.jpg 300w, https:\/\/f6kmf.fr\/wp-content\/uploads\/2022\/09\/IMG_20220920_184846-768x432.jpg 768w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><\/figure>\n\n\n\n<p class=\"has-background has-pale-cyan-blue-background-color\">Le gain th\u00e9orique est faible, de l\u2019ordre de 4.5DBI (Le gain de l&rsquo;antenne isotrope est de = 0 dBi, un dip\u00f4le a un gain th\u00e9orique de 2,15 dB sup\u00e9rieur \u00e0 celui d&rsquo;une antenne isotrope, notre antenne pr\u00e9sente donc un gain de 4,5 &#8211; 2,15 soit 2,35 dB par rapport au dip\u00f4le), mais elle est omnidirectionnelle.<\/p>\n\n\n\n<p class=\"has-background has-very-light-gray-background-color\">Dimensions d\u2019un p\u00e9tale.<br>Pour 436Mhz, la longueur d&rsquo;onde (et donc la longueur total du fil d&rsquo;un p\u00e9tale) est de 300\/436 = 0.69 m, avec 34 cm pour la 1\/2 onde et 17 cm pour les 1\/4 d&rsquo;onde.<\/p>\n\n\n\n<div class=\"wp-block-image\"><figure class=\"aligncenter\"><img loading=\"lazy\" decoding=\"async\" width=\"392\" height=\"294\" src=\"https:\/\/f6kmf.fr\/wp-content\/uploads\/2022\/09\/image-1.png\" alt=\"\" class=\"wp-image-2291\" srcset=\"https:\/\/f6kmf.fr\/wp-content\/uploads\/2022\/09\/image-1.png 392w, https:\/\/f6kmf.fr\/wp-content\/uploads\/2022\/09\/image-1-300x225.png 300w\" sizes=\"auto, (max-width: 392px) 100vw, 392px\" \/><\/figure><\/div>\n\n\n\n<p class=\"has-background has-pale-cyan-blue-background-color\">Le premier prototype est r\u00e9alis\u00e9 en c\u00e2ble \u00e9lectrique de diam\u00e8tre 2.5 mm, c&rsquo;est suffisant pour la rigidit\u00e9 de cette antenne qui reste de petite taille, les p\u00e9tales sont directement soud\u00e9s sur une fiche BNC.  Chaque brin part de la partie centrale de la BNC et va rejoindre le socle, la partie 1\/2 onde fait un angle de 45\u00b0 avec le plan de sol, les p\u00e9tales sont donc tous inclin\u00e9s.<\/p>\n\n\n\n<figure class=\"wp-block-image\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"726\" src=\"https:\/\/f6kmf.fr\/wp-content\/uploads\/2022\/09\/image-5-1024x726.png\" alt=\"\" class=\"wp-image-2298\" srcset=\"https:\/\/f6kmf.fr\/wp-content\/uploads\/2022\/09\/image-5-1024x726.png 1024w, https:\/\/f6kmf.fr\/wp-content\/uploads\/2022\/09\/image-5-300x213.png 300w, https:\/\/f6kmf.fr\/wp-content\/uploads\/2022\/09\/image-5-768x545.png 768w, https:\/\/f6kmf.fr\/wp-content\/uploads\/2022\/09\/image-5.png 1148w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><\/figure>\n\n\n\n<p class=\"has-background has-very-light-gray-background-color\">Les mesures sur le prototype sont particuli\u00e8rement encourageantes, la bande passante est large, l&rsquo;imp\u00e9dance et le rapport d&rsquo;ondes stationnaires (ROS ou SWR) plus que satisfaisants !<\/p>\n\n\n\n<figure class=\"wp-block-image\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"596\" src=\"https:\/\/f6kmf.fr\/wp-content\/uploads\/2022\/09\/image-2-1024x596.png\" alt=\"\" class=\"wp-image-2293\" srcset=\"https:\/\/f6kmf.fr\/wp-content\/uploads\/2022\/09\/image-2-1024x596.png 1024w, https:\/\/f6kmf.fr\/wp-content\/uploads\/2022\/09\/image-2-300x175.png 300w, https:\/\/f6kmf.fr\/wp-content\/uploads\/2022\/09\/image-2-768x447.png 768w, https:\/\/f6kmf.fr\/wp-content\/uploads\/2022\/09\/image-2.png 1140w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><\/figure>\n\n\n\n<p class=\"has-background has-pale-cyan-blue-background-color\">Finalisons le projet, l&rsquo;antenne est d\u00e9mont\u00e9e puis remont\u00e9e dans un boitier \u00e9lectrique, un peu de silicone assurera l&rsquo;\u00e9tanch\u00e9it\u00e9 au niveau des passages de c\u00e2bles. <\/p>\n\n\n\n<figure class=\"wp-block-image\"><img loading=\"lazy\" decoding=\"async\" width=\"821\" height=\"667\" src=\"https:\/\/f6kmf.fr\/wp-content\/uploads\/2022\/09\/image-3.png\" alt=\"\" class=\"wp-image-2294\" srcset=\"https:\/\/f6kmf.fr\/wp-content\/uploads\/2022\/09\/image-3.png 821w, https:\/\/f6kmf.fr\/wp-content\/uploads\/2022\/09\/image-3-300x244.png 300w, https:\/\/f6kmf.fr\/wp-content\/uploads\/2022\/09\/image-3-768x624.png 768w\" sizes=\"auto, (max-width: 821px) 100vw, 821px\" \/><\/figure>\n\n\n\n<p class=\"has-background has-very-light-gray-background-color\">Quelques essais <br>La balise 432Mhz HB9G est re\u00e7ue 59+10dB <\/p>\n\n\n\n<figure class=\"wp-block-image\"><img loading=\"lazy\" decoding=\"async\" width=\"959\" height=\"546\" src=\"https:\/\/f6kmf.fr\/wp-content\/uploads\/2022\/09\/image-4.png\" alt=\"\" class=\"wp-image-2295\" srcset=\"https:\/\/f6kmf.fr\/wp-content\/uploads\/2022\/09\/image-4.png 959w, https:\/\/f6kmf.fr\/wp-content\/uploads\/2022\/09\/image-4-300x171.png 300w, https:\/\/f6kmf.fr\/wp-content\/uploads\/2022\/09\/image-4-768x437.png 768w\" sizes=\"auto, (max-width: 959px) 100vw, 959px\" \/><\/figure>\n\n\n\n<p class=\"has-background has-pale-cyan-blue-background-color\">Les satellites sont \u00e9galement re\u00e7us alors que l&rsquo;antenne est juste sur le rebord de la fen\u00eatre, les signaux POCSAG ainsi que la bande PMR arrivent bien \u00e9galement.<br>Utilis\u00e9e en \u00e9mission, les relais UHF avoisinants sont d\u00e9clench\u00e9s sans difficult\u00e9.<\/p>\n\n\n\n<figure class=\"wp-block-image\"><img decoding=\"async\" src=\"https:\/\/mail.google.com\/mail\/u\/0?ui=2&amp;ik=0c2f396b52&amp;attid=0.1&amp;permmsgid=msg-a:r-3719195543869691037&amp;th=18365e5aa5a7c249&amp;view=fimg&amp;fur=ip&amp;sz=s0-l75-ft&amp;attbid=ANGjdJ8LV8mfQdH3HpoVSZAlwXZRrgVz5YB_BbngaAjWquEwE9zq1AEoZ-5CaXQdXObiU-IoSl_0BLi8Dp2PIquCWcT7-oU7YCEARQRm8WNX8AarvLDQ-9Ov7RZHZmk&amp;disp=emb&amp;realattid=ii_l8d7xfmj0\" alt=\"image.png\"\/><\/figure>\n\n\n\n<p class=\"has-background has-very-light-gray-background-color\">Voil\u00e0 une antenne facile \u00e0 r\u00e9aliser, vraiment pas ch\u00e8re \u00e0 essayer sur d&rsquo;autres fr\u00e9quences .<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Par Gilles F1EFW Je cherchais une antenne 435\/438Mhz (Fr\u00e9quence descendante de nombreux satellites) facile \u00e0 r\u00e9aliser, \u00e0 polarisation circulaire et<\/p>\n","protected":false},"author":4,"featured_media":2298,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"colormag_page_container_layout":"default_layout","colormag_page_sidebar_layout":"default_layout","footnotes":""},"categories":[21,14,8],"tags":[],"class_list":["post-2289","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-antenne","category-realisations","category-satellites"],"_links":{"self":[{"href":"https:\/\/f6kmf.fr\/index.php\/wp-json\/wp\/v2\/posts\/2289","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/f6kmf.fr\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/f6kmf.fr\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/f6kmf.fr\/index.php\/wp-json\/wp\/v2\/users\/4"}],"replies":[{"embeddable":true,"href":"https:\/\/f6kmf.fr\/index.php\/wp-json\/wp\/v2\/comments?post=2289"}],"version-history":[{"count":2,"href":"https:\/\/f6kmf.fr\/index.php\/wp-json\/wp\/v2\/posts\/2289\/revisions"}],"predecessor-version":[{"id":2299,"href":"https:\/\/f6kmf.fr\/index.php\/wp-json\/wp\/v2\/posts\/2289\/revisions\/2299"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/f6kmf.fr\/index.php\/wp-json\/wp\/v2\/media\/2298"}],"wp:attachment":[{"href":"https:\/\/f6kmf.fr\/index.php\/wp-json\/wp\/v2\/media?parent=2289"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/f6kmf.fr\/index.php\/wp-json\/wp\/v2\/categories?post=2289"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/f6kmf.fr\/index.php\/wp-json\/wp\/v2\/tags?post=2289"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}