{"id":3683,"date":"2022-09-18T18:45:00","date_gmt":"2022-09-18T08:45:00","guid":{"rendered":"https:\/\/www.homebrewradio.us\/blog\/2022\/09\/18\/building-farhans-pto-but-is-this-really-a-pto\/"},"modified":"2025-07-22T18:02:55","modified_gmt":"2025-07-22T08:02:55","slug":"building-farhans-pto-but-is-this-really-a-pto","status":"publish","type":"post","link":"https:\/\/www.homebrewradio.us\/blog\/2022\/09\/18\/building-farhans-pto-but-is-this-really-a-pto\/","title":{"rendered":"Building Farhan’s PTO — But Is This Really a PTO?"},"content":{"rendered":"<\/p>\n
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Farhan has a PTO in his Daylight Again transceiver. This caught the attention of homebrewers around the world. Walter down in Orlando built one. Dean KK4DAS and I have built versions also. Dean has a 3D printer and made the coil support used in my version (above). Thanks Dean! <\/b><\/div>\n
I had a little trouble at first because one of the capacitors I had in there was not NP0, so the device drifted a lot. But once I straightened that out (I put in a Silver Mica cap in its place) the oscillator became very stable. Mine moves about 25 kHz with each turn of the bronze screw — this is nicely linear tuning. But I think I will have to use a San Jian counter to keep track of the frequency. The long plastic tube on mine is there to eliminate had capacitance effects. <\/b><\/div>\n

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One of the guys in the Vienna Wireless Society questioned whether we should really call this a PTO. After all, bronze has a permeability equal to that of free space. So we are not really changing the permeability. Frank Harris points out that the bronze screw really acts as a shorted secondary. What do you guys think? Is this a PTO, or do we need another acronym to describe it? <\/b><\/div>\n

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This has been a really fun project. I never built an oscillator like this before. I will probably follow up by building the rest of the Daylight Again rig. <\/b><\/div>\n

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BTW WA6OTP has a nice PTO design: http:\/\/www.wa6otp.com\/pto.htm<\/a><\/b><\/div>\n

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Thanks again to Dean, and to Farhan. <\/b><\/p>\n

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Farhan has a PTO in his Daylight Again transceiver. This caught the attention of homebrewers around the world. Walter down in Orlando built one. Dean KK4DAS and I have built versions also. Dean has a 3D printer and made the coil support used in my version (above). Thanks Dean! I had a little trouble at … Continue reading “Building Farhan’s PTO — But Is This Really a PTO?”<\/span><\/a><\/p>\n","protected":false},"author":2,"featured_media":3684,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[66,263,12,53],"tags":[],"class_list":["post-3683","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-farhan","category-harris-frank","category-tj-dc-rx","category-vfo"],"_links":{"self":[{"href":"https:\/\/www.homebrewradio.us\/blog\/wp-json\/wp\/v2\/posts\/3683","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=3683"}],"version-history":[{"count":1,"href":"https:\/\/www.homebrewradio.us\/blog\/wp-json\/wp\/v2\/posts\/3683\/revisions"}],"predecessor-version":[{"id":3685,"href":"https:\/\/www.homebrewradio.us\/blog\/wp-json\/wp\/v2\/posts\/3683\/revisions\/3685"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.homebrewradio.us\/blog\/wp-json\/wp\/v2\/media\/3684"}],"wp:attachment":[{"href":"https:\/\/www.homebrewradio.us\/blog\/wp-json\/wp\/v2\/media?parent=3683"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.homebrewradio.us\/blog\/wp-json\/wp\/v2\/categories?post=3683"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.homebrewradio.us\/blog\/wp-json\/wp\/v2\/tags?post=3683"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}