{"id":38,"date":"2010-08-15T20:57:17","date_gmt":"2010-08-15T20:57:17","guid":{"rendered":"http:\/\/ava.upuaut.net\/?p=38"},"modified":"2010-08-15T20:57:17","modified_gmt":"2010-08-15T20:57:17","slug":"ntx2-radios-and-resistors","status":"publish","type":"post","link":"https:\/\/ava.upuaut.net\/?p=38","title":{"rendered":"NTX2, Radios and Resistors"},"content":{"rendered":"<p>My NTX2 (434.075) was wired up to the rest of the flight computer. Using Rob Harrisons code at <a href=\"http:\/\/www.pegasushabproject.org.uk\/wiki\/doku.php\/ideas:notes?s[]=ntx2\">http:\/\/www.pegasushabproject.org.uk\/wiki\/doku.php\/ideas:notes?s[]=ntx2<\/a> it was a quick job to insert this into my code and pass the telemetry string too it. This was the easy bit \ud83d\ude42 The theory is fairly simple.<\/p>\n<p>By adjusting the voltage on the TXD pin between two values (&#8220;MARK&#8221; and a &#8220;SPACE&#8221;) you can effectively make the 1&#8217;s and 0&#8217;s data which can then be decoded by DL-FLDIGI. Normally the carrier shift should be about 425Hz. The NTX2 has a range of 6000Hz over the input voltage range of 0 to 3V. So in theory 425Hz should be a modulation of about 0.2125v between the MARK and SPACE.<\/p>\n<p>The sample circuit above was using 3.3V however on my Arduino the digital high voltage is 5V so I had to amend the voltage divider circuit. After alot of experimentation and alot of silly errors I managed to get the desired carrier shift of 425Hz. One thing to note is make sure you set your pinMode to output or you will get silly errors ( if you don&#8217;t set pinmode to output the low voltage isn&#8217;t 0v it&#8217;s 2v ish).<\/p>\n<p><a href=\"http:\/\/ava.upuaut.net\/wp-content\/uploads\/2010\/08\/ntx2schematic.png\"><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter size-full wp-image-39\" title=\"ntx2schematic\" src=\"\/\/ava.upuaut.net\/wp-content\/uploads\/2010\/08\/ntx2schematic.png\" alt=\"\" width=\"389\" height=\"429\" srcset=\"https:\/\/ava.upuaut.net\/wp-content\/uploads\/2010\/08\/ntx2schematic.png 389w, https:\/\/ava.upuaut.net\/wp-content\/uploads\/2010\/08\/ntx2schematic-272x300.png 272w\" sizes=\"auto, (max-width: 389px) 100vw, 389px\" \/><\/a><\/p>\n<p>This is what I&#8217;ve come up with. Having tested it with my shiny new FT-817 I can confirm it&#8217;s all working \ud83d\ude42<\/p>\n","protected":false},"excerpt":{"rendered":"<p>My NTX2 (434.075) was wired up to the rest of the flight computer. Using Rob Harrisons code at http:\/\/www.pegasushabproject.org.uk\/wiki\/doku.php\/ideas:notes?s[]=ntx2 it was a quick job to insert this into my code and pass the telemetry string too it. This was the &hellip;<\/p>\n<p class=\"read-more\"><a href=\"https:\/\/ava.upuaut.net\/?p=38\">Read more &raquo;<\/a><\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-38","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"_links":{"self":[{"href":"https:\/\/ava.upuaut.net\/index.php?rest_route=\/wp\/v2\/posts\/38","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/ava.upuaut.net\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/ava.upuaut.net\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/ava.upuaut.net\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/ava.upuaut.net\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=38"}],"version-history":[{"count":1,"href":"https:\/\/ava.upuaut.net\/index.php?rest_route=\/wp\/v2\/posts\/38\/revisions"}],"predecessor-version":[{"id":40,"href":"https:\/\/ava.upuaut.net\/index.php?rest_route=\/wp\/v2\/posts\/38\/revisions\/40"}],"wp:attachment":[{"href":"https:\/\/ava.upuaut.net\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=38"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/ava.upuaut.net\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=38"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/ava.upuaut.net\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=38"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}