{"id":613,"date":"2011-11-05T15:50:48","date_gmt":"2011-11-05T15:50:48","guid":{"rendered":"http:\/\/lefars.org.uk\/WPblog\/?p=613"},"modified":"2011-11-05T22:44:58","modified_gmt":"2011-11-05T22:44:58","slug":"91-unun-project","status":"publish","type":"post","link":"https:\/\/lefars.org.uk\/WPblog\/91-unun-project\/","title":{"rendered":"9:1 UnUn Project"},"content":{"rendered":"

This project was a commission on behalf of Frank M1CPD who required a long wire UnUn. Perhaps better known as a Magnetic Longwire Balun<\/em>, it is an impedance transformer whose purpose is to feed a high impedance long wire from a 50ohm unbalanced coaxial input. \u00a0With \u00a0a 9:1 turns ratio, this gives approx. 450ohm output impedance for the long wire.\u00a0The design is on John M0UKD’s website \u00a0http:\/\/www.m0ukd.com\/Magnetic_Long_Wire_UnUn\/index.php<\/a>.<\/p>\n

The toroid used was \u00a0an (Amidon) Iron Powder \u00a0T200-2 core purchased from Ebay (here<\/a>). This is rated at 650W SSB and 400W 100% duty cycle (Digital modes etc.). Note that this is different to the T130-2 (150W) used in John M0UKD’s original article.<\/p>\n

Below some photos taken during construction and some comments.<\/p>\n

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Stuff Needed (but not the feet)<\/p><\/div>\n

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Counted as one wind<\/p><\/div>\n

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Nine turns later (and the feet are still there, must remember to wear black socks)<\/p><\/div>\n

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Cable tied down and soldered (see also the schematic on the website linked above)<\/p><\/div>\n

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Mounted in the Box<\/p><\/div>\n

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And finally finished.<\/p><\/div>\n

73<\/p>\n

 <\/p>\n

Derek M0DXC \u00a0(Email: m0xdc@lefars.org.uk<\/a>)<\/p>\n

[Additional words by John G8DZH 7-Nov-2011]<\/em><\/p>\n

\u00a0Links<\/strong><\/p>\n

Ready-built balun, Unun’s. Plus IP66 enclosures, SO239 sockets, toroids etc. to make your own. \u00a0http:\/\/stores.ebay.co.uk\/urbasket-eu?_trksid=p4340.l2563<\/a><\/p>\n

Further Reading<\/strong><\/p>\n

Amateur Radio (G3TXQ) – UnUn experiments \u00a0http:\/\/www.karinya.net\/g3txq\/unun\/<\/a><\/p>\n

A 9:1 Balun For Your End Fed Antenna by Robert Betts N1KPR http:\/\/www.bobsamerica.com\/9-1balun.html<\/a><\/p>\n

LEFARS Newsletter No. 89. Pages 25-26. My Pet UNUN by Dick SV0XBN\/9 (members only – login needed)\u00a0<\/em>\u00a0http:\/\/www.lefars.org.uk\/lefars_website\/members\/newsletters\/issue_89_view.pdf<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

This project was a commission on behalf of Frank M1CPD who required a long wire UnUn. Perhaps better known as a Magnetic Longwire Balun, it is an impedance transformer whose purpose is to feed a high impedance long wire from … Continue reading →<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"gallery","meta":{"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[10],"tags":[],"class_list":["post-613","post","type-post","status-publish","format-gallery","hentry","category-home-construction","post_format-post-format-gallery"],"jetpack_featured_media_url":"","jetpack_shortlink":"https:\/\/wp.me\/p22sia-9T","jetpack_sharing_enabled":true,"jetpack_likes_enabled":true,"_links":{"self":[{"href":"https:\/\/lefars.org.uk\/WPblog\/wp-json\/wp\/v2\/posts\/613","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/lefars.org.uk\/WPblog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/lefars.org.uk\/WPblog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/lefars.org.uk\/WPblog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/lefars.org.uk\/WPblog\/wp-json\/wp\/v2\/comments?post=613"}],"version-history":[{"count":21,"href":"https:\/\/lefars.org.uk\/WPblog\/wp-json\/wp\/v2\/posts\/613\/revisions"}],"predecessor-version":[{"id":622,"href":"https:\/\/lefars.org.uk\/WPblog\/wp-json\/wp\/v2\/posts\/613\/revisions\/622"}],"wp:attachment":[{"href":"https:\/\/lefars.org.uk\/WPblog\/wp-json\/wp\/v2\/media?parent=613"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/lefars.org.uk\/WPblog\/wp-json\/wp\/v2\/categories?post=613"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/lefars.org.uk\/WPblog\/wp-json\/wp\/v2\/tags?post=613"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}