{"id":2411,"date":"2022-09-06T11:11:00","date_gmt":"2022-09-06T01:11:00","guid":{"rendered":"https:\/\/www.homebrewradio.us\/blog\/2022\/09\/06\/michael-ag5vg-builds-a-sub-harmonic-receiver-and-moves-it-to-higher-bands\/"},"modified":"2025-07-22T18:02:55","modified_gmt":"2025-07-22T08:02:55","slug":"michael-ag5vg-builds-a-sub-harmonic-receiver-and-moves-it-to-higher-bands","status":"publish","type":"post","link":"https:\/\/www.homebrewradio.us\/blog\/2022\/09\/06\/michael-ag5vg-builds-a-sub-harmonic-receiver-and-moves-it-to-higher-bands\/","title":{"rendered":"Michael AG5VG Builds a Sub-Harmonic Receiver and Moves it to Higher Bands"},"content":{"rendered":"<p><iframe loading=\"lazy\" allow=\"accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture\" allowfullscreen=\"\" frameborder=\"0\" height=\"247\" src=\"https:\/\/www.youtube.com\/embed\/ggwBIhNiQn0?rel=0\" title=\"YouTube video player\" width=\"440\"><\/iframe><\/p>\n<div><\/div>\n<div><b>Michael AG5VG built a Sub-Harmonic Direct Conversion receiver. But then he took it a step further and moved it up from the 80\/40 meter version that I had built, and used the same concept to run it on 20 meters using an oscillator on 40 meters (after some re-winding of the front-end coils). Using a station from Puerto Rico transmitting on 20 meters as an example, he starts out showing how well the receiver works in sub-harmonic mode (with the oscillator on 40), then quickly switches to normal Direct Conversion mode with the oscillator also on 20 (but using only one diode as the detector) &#8212; he can still hear the Puerto Rican station in that mode. Very cool. <\/b><\/p>\n<p><span style=\"background-color: #fff2cc; color: #1d2228; font-family: \"Helvetica Neue\", Helvetica, Arial, sans-serif; font-size: 13px;\">Good Evening Bill,<\/span><\/p>\n<div><span style=\"background-color: #fff2cc;\"><span style=\"color: #1d2228; font-family: Helvetica Neue, Helvetica, Arial, sans-serif;\"><span style=\"font-size: 13px;\">I built the Polykov and I attached a picture of it. I also used Pete&#8217;s pre audio driver circuit from his <\/span><\/span><a href=\"http:\/\/jessystems.com\/\" rel=\"nofollow noopener noreferrer\" style=\"color: #196ad4; font-family: \"Helvetica Neue\", Helvetica, Arial, sans-serif; font-size: 13px;\" target=\"_blank\">jessystems.com<\/a><span style=\"color: #1d2228; font-family: Helvetica Neue, Helvetica, Arial, sans-serif;\"><span style=\"font-size: 13px;\"> site. Then I used an lm386 as the main audio driver. I could hear ft8 on the 40m band. Then I hooked the output of my lm386 circuit to a conventional set of computer speakers to really hear it. I am currently using an indoor wire antenna along the ground so it&#8217;s certainly not optimal. Very fun build and I&#8217;ll be learning more about it. When I have a better antenna system I&#8217;ll hook it all up and send a video of it.<\/span><\/span><\/span><\/div>\n<div style=\"color: #1d2228; font-family: \"Helvetica Neue\", Helvetica, Arial, sans-serif; font-size: 13px;\"><span style=\"background-color: #fff2cc;\"><br \/><\/span><\/div>\n<div style=\"color: #1d2228; font-family: \"Helvetica Neue\", Helvetica, Arial, sans-serif; font-size: 13px;\"><span style=\"background-color: #fff2cc;\">73s<\/span><\/div>\n<div style=\"color: #1d2228; font-family: \"Helvetica Neue\", Helvetica, Arial, sans-serif; font-size: 13px;\"><span style=\"background-color: #fff2cc;\">MIchael<\/span><\/div>\n<div style=\"color: #1d2228; font-family: \"Helvetica Neue\", Helvetica, Arial, sans-serif; font-size: 13px;\"><span style=\"background-color: #fff2cc;\">AG5VG<\/span><\/div>\n<\/div>\n<div style=\"color: #1d2228; font-family: \"Helvetica Neue\", Helvetica, Arial, sans-serif; font-size: 13px;\"><span style=\"background-color: #fff2cc;\"><br \/><\/span><\/div>\n<div style=\"color: #1d2228; font-family: \"Helvetica Neue\", Helvetica, Arial, sans-serif; font-size: 13px;\">\n<div class=\"separator\" style=\"clear: both; text-align: center;\"><a href=\"https:\/\/blogger.googleusercontent.com\/img\/a\/AVvXsEg_jWI-RlIwNFI6PMxMEB8qWJM5IazlgNBm9RK01pIrrScSr7ifNZgAVgPLsFwrS96_STK8pN7TOE-Al9wOlL9cvp0oT0_NXPqP96NDHc3PiZj-wDcK9rL5Qth2jtpm6xidz2bgUP2BSZdVV44OQo80mRSJhkJGl3whODD3_y19oGx1wR8hU30Rbu7t\" style=\"margin-left: 1em; margin-right: 1em;\"><img loading=\"lazy\" decoding=\"async\" alt=\"\" data-original-height=\"1080\" data-original-width=\"810\" height=\"400\" src=\"https:\/\/www.homebrewradio.us\/blog\/wp-content\/uploads\/2022\/09\/image_1753067665.png\" width=\"300\" \/><\/a><\/div>\n<div class=\"separator\" style=\"clear: both; text-align: center;\"><span style=\"background-color: white;\"><br \/><\/span><\/div>\n<div class=\"separator\" style=\"clear: both; text-align: left;\"><span style=\"background-color: #fff2cc;\">Bill,<\/span><\/p>\n<div><span style=\"background-color: #fff2cc;\"><br clear=\"none\" \/><\/span><\/div>\n<div><span style=\"background-color: #fff2cc;\">I am just using a standard signal generator at 1 vpp output. The volume gets louder with every 100 millivolt I go up, but so does the noise. 0.8vpp was a little low for me so I bumped it up a bit.<\/span><\/div>\n<div><span style=\"background-color: #fff2cc;\"><br clear=\"none\" \/><\/span><\/div>\n<div><span style=\"background-color: #fff2cc;\">The indoor antenna actually did surprising well but I&#8217;m looking forward to putting a wire up into a tree I have here. I just recently moved so I have to setup my outside antenna. I live in the San Antonio, TX area. <\/span><\/div>\n<div><span style=\"background-color: #fff2cc;\"><br clear=\"none\" \/><\/span><\/div>\n<div><span style=\"background-color: #fff2cc;\">I am currently using three stages of audio amplification to be able to really hear it. 1st stage is Pete&#8217;s pre audio driver, then an lm386, then a standard set of computer speakers. <\/span><\/div>\n<div><span style=\"background-color: #fff2cc;\"><br clear=\"none\" \/><\/span><\/div>\n<div><span style=\"background-color: #fff2cc;\">I did plenty of playing around with it last night and the doubling function is so cool how it works. When I was around 3.538 MHz, with the variable cap tuned for the 7Mhz area, I was actually listening to 7.76Mhz, the FT8 frequency for 40 meters. I agree with You and Pete in a podcast you did a bit ago, that FT8 is great for seeing if the band is open and checking receivers with! <\/span><\/div>\n<div><span style=\"background-color: #fff2cc;\"><br clear=\"none\" \/><\/span><\/div>\n<div><span style=\"background-color: #fff2cc;\">The next project is the art of the 3.5 &#8211; 4Mhz analog VFO and use it with the Polykov. I am very dependent on the Arduino\/Si5351 pair as the code is available and easy to hook up.<\/span><\/div>\n<div><span style=\"background-color: #fff2cc;\"><br clear=\"none\" \/><\/span><\/div>\n<div><span style=\"background-color: #fff2cc;\">Will keep you both updated. <\/span><\/div>\n<div><span style=\"background-color: #fff2cc;\"><br clear=\"none\" \/><\/span><\/div>\n<div><span style=\"background-color: #fff2cc;\">73s<\/span><\/div>\n<div><span style=\"background-color: #fff2cc;\">Michael<\/span><\/div>\n<div><span style=\"background-color: #fff2cc;\">AG5VG<\/span><\/div>\n<div><span style=\"background-color: #fff2cc;\"><br \/><\/span><\/div>\n<div><span style=\"background-color: white;\"><b>Two more videos from Michael: <\/b><\/span><\/div>\n<div><span style=\"background-color: white;\"><b><br \/><\/b><\/span><\/div>\n<div>\n<div style=\"background-color: white;\"><b>Testing<\/b><\/div>\n<div style=\"background-color: white;\"><a href=\"https:\/\/youtu.be\/kRLBnvqND_w\" rel=\"nofollow noopener noreferrer\" style=\"color: #338fe9;\" target=\"_blank\"><b>https:\/\/youtu.be\/kRLBnvqND_w<\/b><\/a><\/div>\n<div style=\"background-color: white;\"><b><br \/><\/b><\/div>\n<div style=\"background-color: white;\"><b>Operation<\/b><\/div>\n<div style=\"background-color: white;\"><a href=\"https:\/\/youtu.be\/0XUlOlMYkOY\" rel=\"nofollow noopener noreferrer\" style=\"color: #196ad4;\" target=\"_blank\"><b>https:\/\/youtu.be\/0XUlOlMYkOY<\/b><\/a><\/div>\n<div style=\"background-color: white;\"> <\/div>\n<div style=\"background-color: white;\"><span><b>I think this is a great example of good experimenting. Michael took the concept, made some mods, and put the device on another band. FB. <\/b><\/span><\/div>\n<\/div>\n<\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"<p>Michael AG5VG built a Sub-Harmonic Direct Conversion receiver. But then he took it a step further and moved it up from the 80\/40 meter version that I had built, and used the same concept to run it on 20 meters using an oscillator on 40 meters (after some re-winding of the front-end coils). Using a &hellip; <a href=\"https:\/\/www.homebrewradio.us\/blog\/2022\/09\/06\/michael-ag5vg-builds-a-sub-harmonic-receiver-and-moves-it-to-higher-bands\/\" class=\"more-link\">Continue reading<span class=\"screen-reader-text\"> &#8220;Michael AG5VG Builds a Sub-Harmonic Receiver and Moves it to Higher Bands&#8221;<\/span><\/a><\/p>\n","protected":false},"author":2,"featured_media":2412,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[20,35,41,34,356],"tags":[],"class_list":["post-2411","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-20-meters","category-direct-conversion","category-juliano-pete","category-mixer-theory","category-sub-harmonic-mixer"],"_links":{"self":[{"href":"https:\/\/www.homebrewradio.us\/blog\/wp-json\/wp\/v2\/posts\/2411","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=2411"}],"version-history":[{"count":1,"href":"https:\/\/www.homebrewradio.us\/blog\/wp-json\/wp\/v2\/posts\/2411\/revisions"}],"predecessor-version":[{"id":2413,"href":"https:\/\/www.homebrewradio.us\/blog\/wp-json\/wp\/v2\/posts\/2411\/revisions\/2413"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.homebrewradio.us\/blog\/wp-json\/wp\/v2\/media\/2412"}],"wp:attachment":[{"href":"https:\/\/www.homebrewradio.us\/blog\/wp-json\/wp\/v2\/media?parent=2411"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.homebrewradio.us\/blog\/wp-json\/wp\/v2\/categories?post=2411"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.homebrewradio.us\/blog\/wp-json\/wp\/v2\/tags?post=2411"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}