{"id":3489,"date":"2023-01-29T18:10:00","date_gmt":"2023-01-29T07:10:00","guid":{"rendered":"https:\/\/www.homebrewradio.us\/blog\/2023\/01\/29\/rick-n3fjz-builds-the-mixer-for-the-high-school-direct-conversion-receiver\/"},"modified":"2025-07-22T18:02:54","modified_gmt":"2025-07-22T08:02:54","slug":"rick-n3fjz-builds-the-mixer-for-the-high-school-direct-conversion-receiver","status":"publish","type":"post","link":"https:\/\/www.homebrewradio.us\/blog\/2023\/01\/29\/rick-n3fjz-builds-the-mixer-for-the-high-school-direct-conversion-receiver\/","title":{"rendered":"Rick N3FJZ Builds the Mixer for the High School Direct Conversion Receiver"},"content":{"rendered":"<p><iframe loading=\"lazy\" allow=\"accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share\" allowfullscreen=\"\" frameborder=\"0\" height=\"247\" src=\"https:\/\/www.youtube.com\/embed\/z_cpXtWCZ-8?rel=0\" title=\"YouTube video player\" width=\"440\"><\/iframe><\/p>\n<div><\/div>\n<div><b>Wonderful progress from Rick N3FJZ. Having completed the PTO, Rick went on to build the diode ring mixer and diplexer. (See video above.) He then connected these to boards to a band pass filter and an AF amp from previous project. And wow, the resulting receiver sounds really great! I think it sounds better than the ones Dean and I have built. <\/b><\/div>\n<div><b><br \/><\/b><\/div>\n<div><b>&#8212; It will be interesting to see how Rick&#8217;s receiver sounds with the very simple AF amplifier that we are using. <\/b><\/div>\n<div><b><br \/><\/b><\/div>\n<div><b>&#8212; We need to get Rick a coil form for the PTO variable inductor! And getting him the PTO form will allow him to dispense with the varactor circuit (which, I must say, is pretty cool). <\/b><\/div>\n<div><b><br \/><\/b><\/div>\n<div><b>&#8212; In the PTO, for the coupling capacitor (C15) , I now have a 260 pF NP0 cap. But your .1 uF ceramic disc seems to be doing just fin. So maybe we don&#8217;t need the NP0. <\/b><\/div>\n<div><b><br \/><\/b><\/div>\n<div><b>&#8212; I&#8217;m glad that Rick grounded the brass screw. Without that, the hand capacitance effect is bad. <\/b><\/div>\n<div><b><br \/><\/b><\/div>\n<div><b>&#8212; I think results will be much the same with the dual tuned circuit bandpass filter that we use. But it will be interesting to see if Rick&#8217;s triple tuned circuit helps with AM breakthrough (I think I heard Radio Marti when Rick tuned to the top of the band). <\/b><\/div>\n<div><b><br \/><\/b><\/div>\n<div><b>&#8212; I haven&#8217;t had a hum problem and I don&#8217;t think Dean has either. Dean is running his on two 9V batteries. Maybe that would take care of the hum. Our PTOs are completely Al Fresco! <\/b><\/div>\n<div><b><br \/><\/b><\/div>\n<div><b>&#8212; The Traders Net sounds like fun! <\/b><\/div>\n<div><b><br \/><\/b><\/div>\n<div><b>Thanks Rick! 73 <\/b><\/div>\n","protected":false},"excerpt":{"rendered":"<p>Wonderful progress from Rick N3FJZ. Having completed the PTO, Rick went on to build the diode ring mixer and diplexer. (See video above.) He then connected these to boards to a band pass filter and an AF amp from previous project. And wow, the resulting receiver sounds really great! I think it sounds better than &hellip; <a href=\"https:\/\/www.homebrewradio.us\/blog\/2023\/01\/29\/rick-n3fjz-builds-the-mixer-for-the-high-school-direct-conversion-receiver\/\" class=\"more-link\">Continue reading<span class=\"screen-reader-text\"> &#8220;Rick N3FJZ Builds the Mixer for the High School Direct Conversion Receiver&#8221;<\/span><\/a><\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[35,34,365,12],"tags":[],"class_list":["post-3489","post","type-post","status-publish","format-standard","hentry","category-direct-conversion","category-mixer-theory","category-pto","category-tj-dc-rx"],"_links":{"self":[{"href":"https:\/\/www.homebrewradio.us\/blog\/wp-json\/wp\/v2\/posts\/3489","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.homebrewradio.us\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.homebrewradio.us\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.homebrewradio.us\/blog\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.homebrewradio.us\/blog\/wp-json\/wp\/v2\/comments?post=3489"}],"version-history":[{"count":1,"href":"https:\/\/www.homebrewradio.us\/blog\/wp-json\/wp\/v2\/posts\/3489\/revisions"}],"predecessor-version":[{"id":11325,"href":"https:\/\/www.homebrewradio.us\/blog\/wp-json\/wp\/v2\/posts\/3489\/revisions\/11325"}],"wp:attachment":[{"href":"https:\/\/www.homebrewradio.us\/blog\/wp-json\/wp\/v2\/media?parent=3489"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.homebrewradio.us\/blog\/wp-json\/wp\/v2\/categories?post=3489"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.homebrewradio.us\/blog\/wp-json\/wp\/v2\/tags?post=3489"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}