{"id":140,"date":"2015-01-11T21:51:29","date_gmt":"2015-01-11T20:51:29","guid":{"rendered":"http:\/\/www.sevenwatt.com\/main\/?p=140"},"modified":"2016-01-10T14:49:57","modified_gmt":"2016-01-10T13:49:57","slug":"rfm69-bandwidth-investigations-part-1","status":"publish","type":"post","link":"https:\/\/www.sevenwatt.com\/main\/rfm69-bandwidth-investigations-part-1\/","title":{"rendered":"RFM69 Bandwidth investigations part 1"},"content":{"rendered":"<p>Usually there are several 433MHz devices around the house. Remote controls and various sensors. Normally the exact operating frequency is notknown. A lot of work described on the internet is done with wide-band receivers. The following graphs show the relation between the receiver bandwidth and the bandwidth of the received signal.<\/p>\n<p>Frequency sweeps of continuous OOK transmission with different receiver bandwidth settings. The graphs show the variance on the sampled RSSI signal.<br \/>\n<script src=\"\/\/www.sevenwatt.com\/data\/dygraph-combined.js\" type=\"text\/javascript\"><\/script><\/p>\n<div id=\"graphdiv6\" style=\"height: 200px;\"><\/div>\n<div id=\"graphdiv7\" style=\"height: 200px;\"><\/div>\n<div id=\"graphdiv8\" style=\"height: 200px;\"><\/div>\n<p><script type=\"text\/javascript\">\ng1 = new Dygraph(document.getElementById(\"graphdiv6\"),\"\/\/www.sevenwatt.com\/data\/rfm69\/433Freq-BW-VAR-100kHz.csv\",{title: 'Step 100kHz',digitsAfterDecimal: 2, axes: { x: {axisLabelFormatter: function(x) {return Number(x).toPrecision(6);;},}},xlabel: 'f \/ MHz'} );g2 = new Dygraph(document.getElementById(\"graphdiv7\"),\"\/\/www.sevenwatt.com\/data\/rfm69\/433Freq-BW-VAR-25kHz.csv\",{title: 'Step 25kHz', digitsAfterDecimal: 2, axes: { x: {axisLabelFormatter: function(x) {return Number(x).toPrecision(6);;},}},xlabel: 'f \/ MHz'}); g3 = new Dygraph(document.getElementById(\"graphdiv8\"),\"\/\/www.sevenwatt.com\/data\/rfm69\/433Freq-BW-VAR-5kHz.csv\",{title: 'Step 5kHz', digitsAfterDecimal: 2, axes: { x: {axisLabelFormatter: function(x) {return Number(x).toPrecision(6);;},}},xlabel: 'f \/ MHz'});\n<\/script><\/p>\n<p><span style=\"font-size: 1rem; line-height: 1.714285714;\">A rule of thumb is that the sweep is performed with the RFM69 receiver OOK-bandwidth being equal to the frequency step size of the sweep. This gives about 3 datapoints with elevated variance, providing good view to estimate the the peak frequency (433.81MHz for the KAKU remote)First a coarse sweep with steps of 100kHz can be perfoemd, followed by a narrow sweep with step size of 5 or 10kHz.<\/span><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Usually there are several 433MHz devices around the house. Remote controls and various sensors. Normally the exact operating frequency is notknown. A lot of work described on the internet is done with wide-band receivers. The following graphs show the relation between the receiver bandwidth and the bandwidth of the received signal. Frequency sweeps of continuous [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"footnotes":""},"categories":[7,27,15],"tags":[32,29,33,58],"class_list":["post-140","post","type-post","status-publish","format-standard","hentry","category-ook","category-picos-arm","category-rfm69","tag-arduino","tag-chibios","tag-nucleo","tag-ook"],"_links":{"self":[{"href":"https:\/\/www.sevenwatt.com\/main\/wp-json\/wp\/v2\/posts\/140","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.sevenwatt.com\/main\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.sevenwatt.com\/main\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.sevenwatt.com\/main\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.sevenwatt.com\/main\/wp-json\/wp\/v2\/comments?post=140"}],"version-history":[{"count":16,"href":"https:\/\/www.sevenwatt.com\/main\/wp-json\/wp\/v2\/posts\/140\/revisions"}],"predecessor-version":[{"id":593,"href":"https:\/\/www.sevenwatt.com\/main\/wp-json\/wp\/v2\/posts\/140\/revisions\/593"}],"wp:attachment":[{"href":"https:\/\/www.sevenwatt.com\/main\/wp-json\/wp\/v2\/media?parent=140"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.sevenwatt.com\/main\/wp-json\/wp\/v2\/categories?post=140"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.sevenwatt.com\/main\/wp-json\/wp\/v2\/tags?post=140"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}