{"id":2682,"date":"2016-02-27T11:50:00","date_gmt":"2016-02-27T00:50:00","guid":{"rendered":"https:\/\/www.homebrewradio.us\/blog\/2016\/02\/27\/sputnik-replica-transmitter-an-error-in-the-sputnik-schematic-and-why-20-005-mhz\/"},"modified":"2025-07-21T13:43:58","modified_gmt":"2025-07-21T03:43:58","slug":"sputnik-replica-transmitter-an-error-in-the-sputnik-schematic-and-why-20-005-mhz","status":"publish","type":"post","link":"https:\/\/www.homebrewradio.us\/blog\/2016\/02\/27\/sputnik-replica-transmitter-an-error-in-the-sputnik-schematic-and-why-20-005-mhz\/","title":{"rendered":"Sputnik Replica Transmitter, an “Error” in the Sputnik Schematic, and Why 20.005 MHz?"},"content":{"rendered":"
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Mark K6HX pointed me to very interesting <\/b>Hackaday article<\/b><\/a> on Frank PA3CNO’s Sputnik transmitter replica. As blog readers will recall, we went through a period of Sputnik-mania a few years ago: <\/b>http:\/\/soldersmoke.blogspot.com\/search?q=sputnik<\/b><\/a> Chief Designer Comrade Mikhail Rainey AA1TJ sent me some of the Russian tubes (like those pictured above). <\/b><\/div>\n

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The Hackaday article pointed to our post reporting that Oleg RV3GM had found the schematic:<\/b><\/div>\n
http:\/\/soldersmoke.blogspot.com\/2013\/04\/sputnik-schematic-found.html<\/b><\/a> Stefan reports that PA3CNO found “an error” in the original Soviet schematic: <\/b><\/div>\n
http:\/\/www.radio.cc\/post\/Franks-power-supply-for-sputnik<\/b><\/a> A mistake you say? HAH, I say! Hah! This must have been part of a sinister commie plot to prevent the capitalist imperialists from ever being able to reproduce the glorious transmitter of the Soviet people. They almost succeeded. <\/b><\/div>\n

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Just kidding. <\/b><\/div>\n

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In the course of looking through our old Sputnik posts, I came across a question I posted: <\/b><\/div>\n

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I have a question: OK so the crafty Soviets picked 20.005 MHz for some good reasons: Being so close to the WWV freq, it would be easy for hams and SWLs to find it with precision. In the November\/December 2007 issue of “Break In” (from NZ — thanks Jonathan-san!) ZL3DW notes that this frequency selection would allow a receiver set to exactly 20 MHz to “produce an audio tone plus or minus the Doppler shift without ever going through zero beat.” But zero beat with what? Most of the receivers out there would not have had BFOs, right? So the Soviets wouldn’t have been using ordinary CW, right? Were they using AM, with the beeps produced by an audio oscillator modulating the carrier?<\/i> <\/span><\/span><\/div>\n

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Was their diabolical plan to use WWV as the BFO for those using ordinary AM SW receivers? If so, a 5 kHz separation from WWV seems to be too much right? Especially when the Doppler shift on approach would push the frequency up a bit. Maybe they just chose this freq to make it easy for listeners to find — just a bit above WWV. Comrade Rainey surmised that they were keying the PA stage — the oscillator “backwave” was at times audible on the ground. <\/span><\/span><\/div>\n
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What do you think Comrades? <\/span><\/span><\/div>\n
DSW and 73.<\/span><\/span><\/div>\n","protected":false},"excerpt":{"rendered":"

Mark K6HX pointed me to very interesting Hackaday article on Frank PA3CNO’s Sputnik transmitter replica. As blog readers will recall, we went through a period of Sputnik-mania a few years ago: http:\/\/soldersmoke.blogspot.com\/search?q=sputnik Chief Designer Comrade Mikhail Rainey AA1TJ sent me some of the Russian tubes (like those pictured above). The Hackaday article pointed to our … Continue reading “Sputnik Replica Transmitter, an “Error” in the Sputnik Schematic, and Why 20.005 MHz?”<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":2683,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[166,127,86,96,82,32,101],"tags":[],"class_list":["post-2682","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-netherlands","category-new-zealand","category-rainey-michael","category-russia","category-satellites","category-space-program","category-tubes"],"_links":{"self":[{"href":"https:\/\/www.homebrewradio.us\/blog\/wp-json\/wp\/v2\/posts\/2682","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=2682"}],"version-history":[{"count":1,"href":"https:\/\/www.homebrewradio.us\/blog\/wp-json\/wp\/v2\/posts\/2682\/revisions"}],"predecessor-version":[{"id":2685,"href":"https:\/\/www.homebrewradio.us\/blog\/wp-json\/wp\/v2\/posts\/2682\/revisions\/2685"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.homebrewradio.us\/blog\/wp-json\/wp\/v2\/media\/2683"}],"wp:attachment":[{"href":"https:\/\/www.homebrewradio.us\/blog\/wp-json\/wp\/v2\/media?parent=2682"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.homebrewradio.us\/blog\/wp-json\/wp\/v2\/categories?post=2682"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.homebrewradio.us\/blog\/wp-json\/wp\/v2\/tags?post=2682"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}