{"id":4534,"date":"2017-10-08T11:08:00","date_gmt":"2017-10-08T00:08:00","guid":{"rendered":"https:\/\/www.homebrewradio.us\/blog\/2017\/10\/08\/a-direct-conversion-iphone\/"},"modified":"2025-07-21T17:21:35","modified_gmt":"2025-07-21T07:21:35","slug":"a-direct-conversion-iphone","status":"publish","type":"post","link":"https:\/\/www.homebrewradio.us\/blog\/2017\/10\/08\/a-direct-conversion-iphone\/","title":{"rendered":"A Direct Conversion iPhone!"},"content":{"rendered":"
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Well, really a DC receiver in an iPhone box.<\/b><\/div>\n

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I think the Apple iPhone boxes have great potential as project enclosures. They are cardboard, but they are very rigid and solid. I decided to use them for a Direct Conversion receiver project I’ve had in mind. <\/b><\/div>\n
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This is a 40 meter DC receiver. No chips. Ceramic resonator VXO tuned by a varactor diode. 9V battery as the power source. Ear buds as the transducer. Passive, two diode, singly balanced detector. It sounds great — so great that I may have to add a gain control. <\/b><\/div>\n

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The nice fit is no coincidence — I cut the board so it would fit in the iPhone box. <\/b> <\/div>\n

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Take a look at that top cover. It is all, well, empty. I could put another board in there, right? Maybe a balanced modulator, a mic amp and an RF amplifier. Then this thing would be a Double Sideband transceiver. We could even make use of the little microphone that comes with most of the ear buds. <\/b><\/div>\n
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I’m thinking that this might be the kind of project that people would like to take on this winter. Build the VXO first. Then the AF amp. Then the product detector and front end. At that point you’ve built a receiver. For extra credit you could go on to the transmitter. No need to use Apple boxes (but they are cool…) I will try to get the schematic done soon. My nephew John Henry will test the prototype. <\/b><\/div>\n

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Well, really a DC receiver in an iPhone box. I think the Apple iPhone boxes have great potential as project enclosures. They are cardboard, but they are very rigid and solid. I decided to use them for a Direct Conversion receiver project I’ve had in mind. This is a 40 meter DC receiver. No chips. … Continue reading “A Direct Conversion iPhone!”<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":4535,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[35,33],"tags":[],"class_list":["post-4534","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-direct-conversion","category-dsb"],"_links":{"self":[{"href":"https:\/\/www.homebrewradio.us\/blog\/wp-json\/wp\/v2\/posts\/4534","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\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.homebrewradio.us\/blog\/wp-json\/wp\/v2\/comments?post=4534"}],"version-history":[{"count":1,"href":"https:\/\/www.homebrewradio.us\/blog\/wp-json\/wp\/v2\/posts\/4534\/revisions"}],"predecessor-version":[{"id":4539,"href":"https:\/\/www.homebrewradio.us\/blog\/wp-json\/wp\/v2\/posts\/4534\/revisions\/4539"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.homebrewradio.us\/blog\/wp-json\/wp\/v2\/media\/4535"}],"wp:attachment":[{"href":"https:\/\/www.homebrewradio.us\/blog\/wp-json\/wp\/v2\/media?parent=4534"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.homebrewradio.us\/blog\/wp-json\/wp\/v2\/categories?post=4534"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.homebrewradio.us\/blog\/wp-json\/wp\/v2\/tags?post=4534"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}