{"id":536,"date":"2024-12-28T02:05:42","date_gmt":"2024-12-28T01:05:42","guid":{"rendered":"https:\/\/lipkowski.com\/?p=536"},"modified":"2024-12-28T02:18:38","modified_gmt":"2024-12-28T01:18:38","slug":"altoids-tin-bandpass-filter-for-868mhz-meshtastic","status":"publish","type":"post","link":"https:\/\/lipkowski.com\/pl\/2024\/12\/28\/altoids-tin-bandpass-filter-for-868mhz-meshtastic\/","title":{"rendered":"Filtr na 868MHz do Meshtastic z metalowego opakowania do cukierk\u00f3w"},"content":{"rendered":"<p>Sieci kratowe LoRA ostatnio zdobywaj\u0105 wi\u0119ksz\u0105 popularno\u015b\u0107, w szczeg\u00f3lno\u015bci projekt Meshtastic.<\/p>\n<p>Dost\u0119pne modu\u0142y maj\u0105 bardzo szerokie filtry pasmowe odbiornika, przez co odbi\u00f3r mo\u017ce by\u0107 zak\u0142\u00f3cony przez silne syga\u0142y pozapasmowe. Mo\u017cna je wyfiltrowa\u0107 za pomoc\u0105 prostego filtru z metalowej puszki na cukierki (tzw puszka Altoids) i pare kawa\u0142k\u00f3w kabla koncentrycznego semirigid. Konstrukcja bazuje na filtrze na 901MHz publikacji W1GHZ <a href=\"https:\/\/w1ghz.org\/filter\/Altoids_Tin_Filters.pdf\">Altoids Tin Filters<\/a>, ale przestrojonego troch\u0119 ni\u017cej.<\/p>\n<figure id=\"attachment_537\" aria-describedby=\"caption-attachment-537\" style=\"width: 525px\" class=\"wp-caption alignnone\"><a href=\"https:\/\/lipkowski.com\/wp-content\/uploads\/2024\/12\/filter868_1.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"size-large wp-image-537\" src=\"https:\/\/lipkowski.com\/wp-content\/uploads\/2024\/12\/filter868_1-1024x768.jpg\" alt=\"868MHz filter\" width=\"525\" height=\"394\" srcset=\"https:\/\/lipkowski.com\/wp-content\/uploads\/2024\/12\/filter868_1-1024x768.jpg 1024w, https:\/\/lipkowski.com\/wp-content\/uploads\/2024\/12\/filter868_1-300x225.jpg 300w, https:\/\/lipkowski.com\/wp-content\/uploads\/2024\/12\/filter868_1-768x576.jpg 768w, https:\/\/lipkowski.com\/wp-content\/uploads\/2024\/12\/filter868_1.jpg 1200w\" sizes=\"auto, (max-width: 525px) 100vw, 525px\" \/><\/a><figcaption id=\"caption-attachment-537\" class=\"wp-caption-text\">868MHz filter<\/figcaption><\/figure>\n<h4><!--more--><\/h4>\n<h4>Konstrukcja<\/h4>\n<p>Najpier prosz\u0119 przeczyta\u0107 orginalny opis W1GHZ, tak konstrukcja jest bardzo podobna.<\/p>\n<p>Filtr jest zbudowany w stalowej puszcze po cukierkach o wymiarach bardzo podobnych do pude\u0142ek od cukierk\u00f3w Altoids (57x91mm wewn\u0105trz, wysoko\u015b\u0107 21mm).<\/p>\n<p>Rezonatory zosta\u0142y wykonane z 53mm kabla semirigid: z odcinka 55mm zosta\u0142o odci\u0119te 2mm aby uzyska\u0107 dost\u0119p do \u017cy\u0142y \u015brodkowej aby mo\u017cna j\u0105 by\u0142o wyci\u0105gn\u0105\u0107 z kabla. \u017by\u0142a \u015brodkowa zosta\u0142a wyprowadzona na zewn\u0105trz obudowy przez otwory 1.5mm.<\/p>\n<p>Osie rezonator\u00f3w s\u0105 17mm od siebie i oko\u0142o 8-10mm od do\u0142y puszki.<\/p>\n<p>Wej\u015bcie i wyj\u015bcie jest pod\u0142\u0105czone do rezonator\u00f3w 11mm od masy za pomoc\u0105 gniazd SMA.<\/p>\n<p>Pude\u0142ko zosta\u0142o dok\u0142adnie oczyszczone z resztek kalafonii za pomoc\u0105 izopropanolu, zalutowane i zestrojone za pomoc\u0105 delikatnego przesuwania \u017cy\u0142 \u015brodkowych, jednocze\u015bnie przeginaj\u0105c je aby dotyka\u0142y obudowy. Po zestojeniu filtra \u017cy\u0142y zosta\u0142y przylutowane na sta\u0142e do onudowy.<\/p>\n<h4>Results<\/h4>\n<p>Na 868MHz filtr ma t\u0142umienie fali odbitej -20.9dB (SWR 1:1.2) i wnosi -0.63dB t\u0142umienia. To t\u0142umienie jest ni\u017csze ni\u017c podane przez autora publikacji na kt\u00f3rej si\u0119 wzorowa\u0142em.<\/p>\n<p>Cz\u0119stotliwo\u015bci marker\u00f3w na poni\u017cszych wykresach:<\/p>\n<p>1. 868MHz\u00a0\u00a0 2. 853MHz\u00a0\u00a0 3. 901MHz\u00a0\u00a0 4. 808MHz\u00a0\u00a0 5. 934MHz<\/p>\n<p><a href=\"https:\/\/lipkowski.com\/wp-content\/uploads\/2024\/12\/filtr_868_1.png\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-538\" src=\"https:\/\/lipkowski.com\/wp-content\/uploads\/2024\/12\/filtr_868_1.png\" alt=\"\" width=\"608\" height=\"505\" srcset=\"https:\/\/lipkowski.com\/wp-content\/uploads\/2024\/12\/filtr_868_1.png 608w, https:\/\/lipkowski.com\/wp-content\/uploads\/2024\/12\/filtr_868_1-300x249.png 300w\" sizes=\"auto, (max-width: 608px) 100vw, 608px\" \/><\/a><\/p>\n<p><a href=\"https:\/\/lipkowski.com\/wp-content\/uploads\/2024\/12\/filrt_868_RL.png\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-539\" src=\"https:\/\/lipkowski.com\/wp-content\/uploads\/2024\/12\/filrt_868_RL.png\" alt=\"\" width=\"608\" height=\"506\" srcset=\"https:\/\/lipkowski.com\/wp-content\/uploads\/2024\/12\/filrt_868_RL.png 608w, https:\/\/lipkowski.com\/wp-content\/uploads\/2024\/12\/filrt_868_RL-300x250.png 300w\" sizes=\"auto, (max-width: 608px) 100vw, 608px\" \/><\/a><\/p>\n<p><a href=\"https:\/\/lipkowski.com\/wp-content\/uploads\/2024\/12\/filrt_868_SWR.png\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-540\" src=\"https:\/\/lipkowski.com\/wp-content\/uploads\/2024\/12\/filrt_868_SWR.png\" alt=\"\" width=\"609\" height=\"505\" srcset=\"https:\/\/lipkowski.com\/wp-content\/uploads\/2024\/12\/filrt_868_SWR.png 609w, https:\/\/lipkowski.com\/wp-content\/uploads\/2024\/12\/filrt_868_SWR-300x249.png 300w\" sizes=\"auto, (max-width: 609px) 100vw, 609px\" \/><\/a><\/p>\n<p><a href=\"https:\/\/lipkowski.com\/wp-content\/uploads\/2024\/12\/filrt_868_freqs.png\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-541\" src=\"https:\/\/lipkowski.com\/wp-content\/uploads\/2024\/12\/filrt_868_freqs.png\" alt=\"\" width=\"347\" height=\"826\" srcset=\"https:\/\/lipkowski.com\/wp-content\/uploads\/2024\/12\/filrt_868_freqs.png 347w, https:\/\/lipkowski.com\/wp-content\/uploads\/2024\/12\/filrt_868_freqs-126x300.png 126w\" sizes=\"auto, (max-width: 347px) 100vw, 347px\" \/><\/a><\/p>\n<p>Pomiary zosta\u0142y wykonane za pomoc\u0105 NanoVNA v2, skalibrowanego tu\u017c przed wykonaniem pomiar\u00f3w.<\/p>\n<p>VY 73 DE<\/p>\n<p>Jacek \/ SQ5BPF<\/p>\n","protected":false},"excerpt":{"rendered":"<p>LoRA mesh networking is gaining a lot of popularity, especially Meshtastic. The available modules have very lax bandpass filtering. This can be fixed by a simple filter from a tinned still can and some semirigid coax.\u00a0 The construction is based upon the W1GHZ Altoids Tin Filters publication for 901MHz, but tuned a bit lower.<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[22],"tags":[],"class_list":["post-536","post","type-post","status-publish","format-standard","hentry","category-meshtastic"],"translation":{"provider":"WPGlobus","version":"3.0.1","language":"pl","enabled_languages":["en","pl"],"languages":{"en":{"title":true,"content":true,"excerpt":false},"pl":{"title":true,"content":true,"excerpt":false}}},"_links":{"self":[{"href":"https:\/\/lipkowski.com\/pl\/wp-json\/wp\/v2\/posts\/536","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/lipkowski.com\/pl\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/lipkowski.com\/pl\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/lipkowski.com\/pl\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/lipkowski.com\/pl\/wp-json\/wp\/v2\/comments?post=536"}],"version-history":[{"count":11,"href":"https:\/\/lipkowski.com\/pl\/wp-json\/wp\/v2\/posts\/536\/revisions"}],"predecessor-version":[{"id":552,"href":"https:\/\/lipkowski.com\/pl\/wp-json\/wp\/v2\/posts\/536\/revisions\/552"}],"wp:attachment":[{"href":"https:\/\/lipkowski.com\/pl\/wp-json\/wp\/v2\/media?parent=536"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/lipkowski.com\/pl\/wp-json\/wp\/v2\/categories?post=536"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/lipkowski.com\/pl\/wp-json\/wp\/v2\/tags?post=536"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}