{"id":40723,"date":"2019-11-21T08:05:58","date_gmt":"2019-11-21T12:05:58","guid":{"rendered":"https:\/\/swling.com\/blog\/?p=40723"},"modified":"2019-11-21T08:05:58","modified_gmt":"2019-11-21T12:05:58","slug":"am-radio-from-a-hand-wound-coil-and-an-oxidized-british-penny","status":"publish","type":"post","link":"https:\/\/swling.com\/blog\/2019\/11\/am-radio-from-a-hand-wound-coil-and-an-oxidized-british-penny\/","title":{"rendered":"AM radio from a hand-wound coil\u00a0and an oxidized British penny"},"content":{"rendered":"<p><a href=\"https:\/\/swling.com\/blog\/wp-content\/uploads\/2019\/11\/Screen-Shot-2019-11-21-at-07.06.18.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-40724\" src=\"https:\/\/swling.com\/blog\/wp-content\/uploads\/2019\/11\/Screen-Shot-2019-11-21-at-07.06.18.jpg\" alt=\"\" width=\"800\" height=\"409\" srcset=\"https:\/\/swling.com\/blog\/wp-content\/uploads\/2019\/11\/Screen-Shot-2019-11-21-at-07.06.18.jpg 800w, https:\/\/swling.com\/blog\/wp-content\/uploads\/2019\/11\/Screen-Shot-2019-11-21-at-07.06.18-300x153.jpg 300w, https:\/\/swling.com\/blog\/wp-content\/uploads\/2019\/11\/Screen-Shot-2019-11-21-at-07.06.18-768x393.jpg 768w, https:\/\/swling.com\/blog\/wp-content\/uploads\/2019\/11\/Screen-Shot-2019-11-21-at-07.06.18-624x319.jpg 624w\" sizes=\"auto, (max-width: 800px) 100vw, 800px\" \/><\/a><\/p>\n<p>Many thanks to\u00a0<em>SWLing Post<\/em>\u00a0contributor,\u00a0<a href=\"http:\/\/w4.vp9kf.com\/\" target=\"_blank\" rel=\"noopener noreferrer\">Paul Evans<\/a>, who shares the following video and article <a href=\"https:\/\/hackaday.com\/2019\/11\/15\/a-radio-for-the-apocalypse\/\" target=\"_blank\" rel=\"noopener noreferrer\">via <strong>Hackaday<\/strong><\/a>:<\/p>\n<p><span class=\"embed-youtube\" style=\"text-align:center; display: block;\"><iframe loading=\"lazy\" class=\"youtube-player\" width=\"625\" height=\"352\" src=\"https:\/\/www.youtube.com\/embed\/bUMXc6fi7yk?version=3&#038;rel=1&#038;showsearch=0&#038;showinfo=1&#038;iv_load_policy=1&#038;fs=1&#038;hl=en-US&#038;autohide=2&#038;wmode=transparent\" allowfullscreen=\"true\" style=\"border:0;\" sandbox=\"allow-scripts allow-same-origin allow-popups allow-presentation allow-popups-to-escape-sandbox\"><\/iframe><\/span><\/p>\n<blockquote><p>There\u2019s been a spate of apocalypse related articles over the last few weeks, but when I saw <a href=\"https:\/\/www.youtube.com\/watch?v=bUMXc6fi7yk\" target=\"_blank\" rel=\"noopener noreferrer\">an AM radio made from a hand-wound coil<\/a>\u00a0and an oxidized British penny, I couldn\u2019t help but be impressed. We\u2019ve covered\u00a0<a href=\"https:\/\/hackaday.com\/2016\/04\/21\/hacking-when-it-counts-pow-canteen-radios\/\">foxhole radios<\/a>, stereotypical radios that are cobbled together from found parts during wartime.<\/p>\n<p>This example uses a variable capacitor for tuning, but that\u2019s technically optional. All that\u2019s really needed is a coil and something to work as a diode. Surprisingly, copper oxide is a semiconductor, and the surface oxidation on a penny is enough to form a rudimentary diode.[&#8230;]<\/p>\n<p style=\"text-align: center;\"><strong><a href=\"https:\/\/hackaday.com\/2019\/11\/15\/a-radio-for-the-apocalypse\/\" target=\"_blank\" rel=\"noopener noreferrer\">Click here to read the full article at Hackaday.<\/a><\/strong><\/p>\n<\/blockquote>\n<p>Thanks for sharing this, Paul. I absolutely love simple receivers like this one. In the past, I&#8217;ve built several crystal radios and had great success hearing local AM broadcasters. Indeed, the very first kit I ever built was a crystal radio, then later a foxhole style receiver.<\/p>\n<p><strong><em>Post<\/em> readers:<\/strong> Have you ever built a radio similar to this one that uses an oxidized penny?\u00a0 Please comment!<\/p>\n<p style=\"text-align: center;\"><a href=\"https:\/\/swling.com\/blog\/tag\/crystal-radio\/\">Click here to read posts from our archives that focus on crystal radios<\/a>.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Many thanks to\u00a0SWLing Post\u00a0contributor,\u00a0Paul Evans, who shares the following video and article via Hackaday: There\u2019s been a spate of apocalypse related articles over the last few weeks, but when I saw an AM radio made from a hand-wound coil\u00a0and an oxidized British penny, I couldn\u2019t help but be impressed. We\u2019ve covered\u00a0foxhole radios, stereotypical radios that [&hellip;]<\/p>\n","protected":false},"author":15,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_feature_clip_id":0,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":true,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2},"jetpack_post_was_ever_published":false},"categories":[373,627,3],"tags":[617,3354,7864,8147],"class_list":["post-40723","post","type-post","status-publish","format-standard","hentry","category-am","category-how-to","category-news","tag-crystal-radio","tag-hackaday","tag-paul-evans-w4-vp9kf","tag-penny-crystal-radio"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_shortlink":"https:\/\/wp.me\/pn3uc-aAP","jetpack-related-posts":[{"id":43684,"url":"https:\/\/swling.com\/blog\/2020\/06\/credit-card-crystal-radio\/","url_meta":{"origin":40723,"position":0},"title":"Credit Card Crystal Radio","author":"Thomas","date":"June 3, 2020","format":false,"excerpt":"Many thanks to SWLing Post contributor, Paul Evans, who shares this article from Hackaday that highlights a crystal radio built completely on a smart chip credit card by Billy Cheung. Hackaday notes: This is possible because the smart chip on many credit cards contains a diode. It\u2019s then a simple\u2026","rel":"","context":"In &quot;How To&quot;","block_context":{"text":"How To","link":"https:\/\/swling.com\/blog\/category\/how-to\/"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2020\/06\/crystal-radio-credit-card-e1591183584962.jpeg?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2020\/06\/crystal-radio-credit-card-e1591183584962.jpeg?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2020\/06\/crystal-radio-credit-card-e1591183584962.jpeg?resize=525%2C300&ssl=1 1.5x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2020\/06\/crystal-radio-credit-card-e1591183584962.jpeg?resize=700%2C400&ssl=1 2x"},"classes":[]},{"id":41103,"url":"https:\/\/swling.com\/blog\/2019\/12\/video-tube-radio-transmitter-designs-from-the-1920s\/","url_meta":{"origin":40723,"position":1},"title":"Video: Tube radio transmitter designs from the 1920s","author":"Thomas","date":"December 7, 2019","format":false,"excerpt":"Many thanks to SWLing Post contributor, Paul Evans (W4\/VP9KF), who shares the following article from Hackaday: The origin of the term \u201cbreadboard\u201d comes from an amusing past when wooden bread boards were swiped from kitchens and used as a canvas for radio hobbyists to roll homemade capacitors, inductors, and switches.\u2026","rel":"","context":"In &quot;News&quot;","block_context":{"text":"News","link":"https:\/\/swling.com\/blog\/category\/news\/"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2019\/12\/Antique-Radio.jpg?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2019\/12\/Antique-Radio.jpg?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2019\/12\/Antique-Radio.jpg?resize=525%2C300&ssl=1 1.5x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2019\/12\/Antique-Radio.jpg?resize=700%2C400&ssl=1 2x"},"classes":[]},{"id":38796,"url":"https:\/\/swling.com\/blog\/2019\/08\/hackaday-looks-back-at-the-venerable-rtl-sdr\/","url_meta":{"origin":40723,"position":2},"title":"Hackaday looks back at the venerable RTL-SDR","author":"Thomas","date":"August 3, 2019","format":false,"excerpt":"Many thanks to SWLing Post contributor, Paul Evans (W4\/VP9KF), who shares the following article from Hackaday: Before swearing my fealty to the Jolly Wrencher, I wrote for several other sites, creating more or less the same sort of content I do now. In fact, the topical overlap was enough that\u2026","rel":"","context":"In &quot;News&quot;","block_context":{"text":"News","link":"https:\/\/swling.com\/blog\/category\/news\/"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2017\/03\/RTL-SDR-ADS-B-Rasperry-Pi-PiAware-1024x631.jpg?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2017\/03\/RTL-SDR-ADS-B-Rasperry-Pi-PiAware-1024x631.jpg?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2017\/03\/RTL-SDR-ADS-B-Rasperry-Pi-PiAware-1024x631.jpg?resize=525%2C300&ssl=1 1.5x"},"classes":[]},{"id":38566,"url":"https:\/\/swling.com\/blog\/2019\/07\/a-very-exciting-radio\/","url_meta":{"origin":40723,"position":3},"title":"A very \u201cexciting\u201d radio!","author":"Thomas","date":"July 19, 2019","format":false,"excerpt":"Many thanks to SWLing Post contributor, Paul W4\/VP9KFPaul W4\/VP9KF, who writes: A very exciting radio! One that depends on excited atoms, of a sort... (Source: Hackaday) The basic technology of radio hasn\u2019t changed much since an Italian marquis first blasted telegraph messages across the Atlantic using a souped-up spark plug\u2026","rel":"","context":"In &quot;News&quot;","block_context":{"text":"News","link":"https:\/\/swling.com\/blog\/category\/news\/"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2019\/07\/32664D29-3A1C-4E05-A5B9-7928CA2C81BF-750x1024.jpeg?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2019\/07\/32664D29-3A1C-4E05-A5B9-7928CA2C81BF-750x1024.jpeg?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2019\/07\/32664D29-3A1C-4E05-A5B9-7928CA2C81BF-750x1024.jpeg?resize=525%2C300&ssl=1 1.5x"},"classes":[]},{"id":43043,"url":"https:\/\/swling.com\/blog\/2020\/04\/radio-waves-am-fm-in-teslas-odd-crosleys-cw-club-membership-on-the-rise-and-2020-contest-university-is-free\/","url_meta":{"origin":40723,"position":4},"title":"Radio Waves: AM\/FM in Teslas, Odd Crosleys, CW Club Membership on the Rise, and 2020 Contest University is Free","author":"Thomas","date":"April 29, 2020","format":false,"excerpt":"Radio Waves:\u00a0 Stories Making Waves in the World of Radio Because I keep my ear to the waves, as well as receive many tips from others who do the same, I find myself privy to radio-related stories that might interest\u00a0SWLing Post\u00a0readers.\u00a0 To that end:\u00a0Welcome to the\u00a0SWLing Post\u2019s Radio Waves, a\u2026","rel":"","context":"In &quot;AM&quot;","block_context":{"text":"AM","link":"https:\/\/swling.com\/blog\/category\/am\/"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2015\/02\/Crosley-Dial-1024x678.jpg?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2015\/02\/Crosley-Dial-1024x678.jpg?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2015\/02\/Crosley-Dial-1024x678.jpg?resize=525%2C300&ssl=1 1.5x"},"classes":[]},{"id":66494,"url":"https:\/\/swling.com\/blog\/2026\/07\/hackaday-spotlights-a-clever-diy-si5351-radio-project\/","url_meta":{"origin":40723,"position":5},"title":"Hackaday Spotlights a Clever DIY Si5351 Radio Project","author":"Thomas","date":"July 4, 2026","format":false,"excerpt":"Many thanks to SWLing Post contributor Dennis Dura who notes that\u00a0Hackaday recently featured a clever DIY receiver project based on the Si5351 and ESP32 that covers shortwave, mediumwave, and more. It has a nice retro look, plenty of modern features, and even includes an SDR mode for use with a\u2026","rel":"","context":"In &quot;News&quot;","block_context":{"text":"News","link":"https:\/\/swling.com\/blog\/category\/news\/"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2026\/07\/siradio-1.jpeg?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2026\/07\/siradio-1.jpeg?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2026\/07\/siradio-1.jpeg?resize=525%2C300&ssl=1 1.5x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2026\/07\/siradio-1.jpeg?resize=700%2C400&ssl=1 2x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2026\/07\/siradio-1.jpeg?resize=1050%2C600&ssl=1 3x"},"classes":[]}],"jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/swling.com\/blog\/wp-json\/wp\/v2\/posts\/40723","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/swling.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/swling.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/swling.com\/blog\/wp-json\/wp\/v2\/users\/15"}],"replies":[{"embeddable":true,"href":"https:\/\/swling.com\/blog\/wp-json\/wp\/v2\/comments?post=40723"}],"version-history":[{"count":0,"href":"https:\/\/swling.com\/blog\/wp-json\/wp\/v2\/posts\/40723\/revisions"}],"wp:attachment":[{"href":"https:\/\/swling.com\/blog\/wp-json\/wp\/v2\/media?parent=40723"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/swling.com\/blog\/wp-json\/wp\/v2\/categories?post=40723"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/swling.com\/blog\/wp-json\/wp\/v2\/tags?post=40723"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}