{"id":3992,"date":"2021-07-20T12:22:00","date_gmt":"2021-07-20T02:22:00","guid":{"rendered":"https:\/\/www.homebrewradio.us\/blog\/2021\/07\/20\/mythbuster-videos-8-and-9-the-old-military-radio-net-plus-zero-beat-and-the-vertical-skirts\/"},"modified":"2025-07-22T18:04:39","modified_gmt":"2025-07-22T08:04:39","slug":"mythbuster-videos-8-and-9-the-old-military-radio-net-plus-zero-beat-and-the-vertical-skirts","status":"publish","type":"post","link":"https:\/\/www.homebrewradio.us\/blog\/2021\/07\/20\/mythbuster-videos-8-and-9-the-old-military-radio-net-plus-zero-beat-and-the-vertical-skirts\/","title":{"rendered":"Mythbuster Videos 8 and 9 &#8212; The Old Military Radio Net plus &#8220;Zero Beat and The Vertical Skirts&#8221;"},"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\/k010GUn2wzI?rel=0\" title=\"YouTube video player\" width=\"440\"><\/iframe><\/p>\n<div><\/div>\n<div><span style=\"background-color: #f9f9f9; color: #030303; font-family: Roboto, Arial, sans-serif; font-size: 14px; letter-spacing: 0.2px; white-space: pre-wrap;\"><b>I like to listen to the Old Military Radio Net on Saturday mornings. This week I was listening with the Mythbuster receiver. The AM carriers provided a good opportunity to observe the effects of the steep skirts of the 10 pole crystal filter. We start at zero beat, with the BFO exactly on the carrier frequency. If I turn the VFO dial in one direction, I in effect move the passband in a way that puts the carrier in the passband. And it is no longer zero beat with the BFO, so we hear the heterodyne (the beat!). But if I turn the VFO dial in the other direction, the carrier is now outside the passband. Even though the BFO would produce a tone, we don&#8217;t hear a tone, because those steep filter skirts are keeping the carrier out. We do continue to hear some of the sideband frequencies, because they remain in the passband. The very sharp drop-off of the carrier tone is a good indication that the steep skirts of the crystal filter are doing the job.<\/b><\/span><\/p>\n<div><\/div>\n<div><\/div>\n<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\/OczqkNyh5cw?rel=0\" title=\"YouTube video player\" width=\"440\"><\/iframe><\/div>\n<div><\/div>\n<div><span style=\"background-color: #f9f9f9; color: #030303; font-family: Roboto, Arial, sans-serif; font-size: 14px; letter-spacing: 0.2px; white-space: pre-wrap;\"><b>&#8220;Zero Beat and the Vertical Skirts&#8221; Sounds like the name of a Punk Rock band, doesn&#8217;t it? Anyway in this video I explain what happened in Mythbuster Video #8 (above). I explain why we can hear the Old Military Radio Net carriers when I tune the VFO in one direction, but not in the other.<\/b><\/span><\/div>\n","protected":false},"excerpt":{"rendered":"<p>I like to listen to the Old Military Radio Net on Saturday mornings. This week I was listening with the Mythbuster receiver. The AM carriers provided a good opportunity to observe the effects of the steep skirts of the 10 pole crystal filter. We start at zero beat, with the BFO exactly on the carrier &hellip; <a href=\"https:\/\/www.homebrewradio.us\/blog\/2021\/07\/20\/mythbuster-videos-8-and-9-the-old-military-radio-net-plus-zero-beat-and-the-vertical-skirts\/\" class=\"more-link\">Continue reading<span class=\"screen-reader-text\"> &#8220;Mythbuster Videos 8 and 9 &#8212; The Old Military Radio Net plus &#8220;Zero Beat and The Vertical Skirts&#8221;&#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":[130,16,243,132,23],"tags":[],"class_list":["post-3992","post","type-post","status-publish","format-standard","hentry","category-am","category-filters","category-military-radios","category-mythbuster","category-ssb"],"_links":{"self":[{"href":"https:\/\/www.homebrewradio.us\/blog\/wp-json\/wp\/v2\/posts\/3992","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=3992"}],"version-history":[{"count":1,"href":"https:\/\/www.homebrewradio.us\/blog\/wp-json\/wp\/v2\/posts\/3992\/revisions"}],"predecessor-version":[{"id":11455,"href":"https:\/\/www.homebrewradio.us\/blog\/wp-json\/wp\/v2\/posts\/3992\/revisions\/11455"}],"wp:attachment":[{"href":"https:\/\/www.homebrewradio.us\/blog\/wp-json\/wp\/v2\/media?parent=3992"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.homebrewradio.us\/blog\/wp-json\/wp\/v2\/categories?post=3992"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.homebrewradio.us\/blog\/wp-json\/wp\/v2\/tags?post=3992"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}