{"id":1680,"date":"2021-10-15T19:18:45","date_gmt":"2021-10-15T17:18:45","guid":{"rendered":"https:\/\/pa3csg.nl\/?page_id=1680"},"modified":"2021-10-15T22:42:33","modified_gmt":"2021-10-15T20:42:33","slug":"432mhz-filter-from-ali-express","status":"publish","type":"page","link":"https:\/\/pa3csg.nl\/?page_id=1680","title":{"rendered":"432MHz filter from Ali Express"},"content":{"rendered":"\n<p>I needed a  low pass filter for 432MHz and as usual Ali Express has a solution not to expensive. These were 400-470 MHz low pass filters. Mine started at 385 MHz going down.<\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" width=\"1024\" height=\"891\" src=\"https:\/\/pa3csg.nl\/wp-content\/uploads\/2021\/10\/DSC_6657-1024x891.jpg\" alt=\"\" class=\"wp-image-1683\" srcset=\"https:\/\/pa3csg.nl\/wp-content\/uploads\/2021\/10\/DSC_6657-1024x891.jpg 1024w, https:\/\/pa3csg.nl\/wp-content\/uploads\/2021\/10\/DSC_6657-300x261.jpg 300w, https:\/\/pa3csg.nl\/wp-content\/uploads\/2021\/10\/DSC_6657-600x522.jpg 600w, https:\/\/pa3csg.nl\/wp-content\/uploads\/2021\/10\/DSC_6657-1536x1337.jpg 1536w, https:\/\/pa3csg.nl\/wp-content\/uploads\/2021\/10\/DSC_6657-2048x1783.jpg 2048w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/><\/figure>\n\n\n\n<p>I decided to try and retune them by pulling the small inductors apart. This result in the following plot:<\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" width=\"1024\" height=\"932\" src=\"https:\/\/pa3csg.nl\/wp-content\/uploads\/2021\/10\/DSC_6658-1024x932.jpg\" alt=\"\" class=\"wp-image-1684\" srcset=\"https:\/\/pa3csg.nl\/wp-content\/uploads\/2021\/10\/DSC_6658-1024x932.jpg 1024w, https:\/\/pa3csg.nl\/wp-content\/uploads\/2021\/10\/DSC_6658-300x273.jpg 300w, https:\/\/pa3csg.nl\/wp-content\/uploads\/2021\/10\/DSC_6658-600x546.jpg 600w, https:\/\/pa3csg.nl\/wp-content\/uploads\/2021\/10\/DSC_6658-1536x1397.jpg 1536w, https:\/\/pa3csg.nl\/wp-content\/uploads\/2021\/10\/DSC_6658-2048x1863.jpg 2048w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/><\/figure>\n\n\n\n<p>The loss for each filter was about 2.5 &#8211; 3 dB<\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" width=\"1024\" height=\"925\" src=\"https:\/\/pa3csg.nl\/wp-content\/uploads\/2021\/10\/DSC_6659-1024x925.jpg\" alt=\"\" class=\"wp-image-1686\" srcset=\"https:\/\/pa3csg.nl\/wp-content\/uploads\/2021\/10\/DSC_6659-1024x925.jpg 1024w, https:\/\/pa3csg.nl\/wp-content\/uploads\/2021\/10\/DSC_6659-300x271.jpg 300w, https:\/\/pa3csg.nl\/wp-content\/uploads\/2021\/10\/DSC_6659-600x542.jpg 600w, https:\/\/pa3csg.nl\/wp-content\/uploads\/2021\/10\/DSC_6659-1536x1388.jpg 1536w, https:\/\/pa3csg.nl\/wp-content\/uploads\/2021\/10\/DSC_6659-2048x1850.jpg 2048w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/><\/figure>\n\n\n\n<p>The soldering of the inductors was poor, on one filter I had to resolder the inductors. Sorry for the bad photo!<\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" width=\"1024\" height=\"575\" src=\"https:\/\/pa3csg.nl\/wp-content\/uploads\/2021\/10\/DSC_6660-1024x575.jpg\" alt=\"\" class=\"wp-image-1687\" srcset=\"https:\/\/pa3csg.nl\/wp-content\/uploads\/2021\/10\/DSC_6660-1024x575.jpg 1024w, https:\/\/pa3csg.nl\/wp-content\/uploads\/2021\/10\/DSC_6660-300x168.jpg 300w, https:\/\/pa3csg.nl\/wp-content\/uploads\/2021\/10\/DSC_6660-600x337.jpg 600w, https:\/\/pa3csg.nl\/wp-content\/uploads\/2021\/10\/DSC_6660-1536x862.jpg 1536w, https:\/\/pa3csg.nl\/wp-content\/uploads\/2021\/10\/DSC_6660-678x381.jpg 678w, https:\/\/pa3csg.nl\/wp-content\/uploads\/2021\/10\/DSC_6660.jpg 1782w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/><\/figure>\n","protected":false},"excerpt":{"rendered":"<div class=\"mh-excerpt\"><p>I needed a low pass filter for 432MHz and as usual Ali Express has a solution not to expensive. These were 400-470 MHz low pass <a class=\"mh-excerpt-more\" href=\"https:\/\/pa3csg.nl\/?page_id=1680\" title=\"432MHz filter from Ali Express\">[&#8230;]<\/a><\/p>\n<\/div>","protected":false},"author":1,"featured_media":1686,"parent":0,"menu_order":92,"comment_status":"closed","ping_status":"closed","template":"","meta":[],"categories":[39],"tags":[],"_links":{"self":[{"href":"https:\/\/pa3csg.nl\/index.php?rest_route=\/wp\/v2\/pages\/1680"}],"collection":[{"href":"https:\/\/pa3csg.nl\/index.php?rest_route=\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/pa3csg.nl\/index.php?rest_route=\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/pa3csg.nl\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/pa3csg.nl\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=1680"}],"version-history":[{"count":3,"href":"https:\/\/pa3csg.nl\/index.php?rest_route=\/wp\/v2\/pages\/1680\/revisions"}],"predecessor-version":[{"id":1688,"href":"https:\/\/pa3csg.nl\/index.php?rest_route=\/wp\/v2\/pages\/1680\/revisions\/1688"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/pa3csg.nl\/index.php?rest_route=\/wp\/v2\/media\/1686"}],"wp:attachment":[{"href":"https:\/\/pa3csg.nl\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1680"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/pa3csg.nl\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=1680"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/pa3csg.nl\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=1680"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}