{"id":13317,"date":"2025-02-26T11:13:56","date_gmt":"2025-02-26T05:43:56","guid":{"rendered":"https:\/\/johnsonfrancis.org\/techworld\/?p=13317"},"modified":"2025-02-26T11:56:35","modified_gmt":"2025-02-26T06:26:35","slug":"excellent-swr-for-my-loaded-coil-80m-antenna","status":"publish","type":"post","link":"https:\/\/johnsonfrancis.org\/techworld\/excellent-swr-for-my-loaded-coil-80m-antenna\/","title":{"rendered":"Excellent SWR for my loaded coil 80m antenna!"},"content":{"rendered":"<iframe loading=\"lazy\" width=\"560\" height=\"315\" src=\"https:\/\/www.youtube.com\/embed\/zHyohzo4a9o?si=2ys-V_pU6yjlkTOl\" title=\"YouTube video player\" frameborder=\"0\" allow=\"accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share\" referrerpolicy=\"strict-origin-when-cross-origin\" allowfullscreen><\/iframe>\n\n<p class=\"wp-block-paragraph\">After a lot of effort I have finally achieved SWR of 1.1 for my loaded coil dipole antenna for 80m. Currently it has 12.5m wire on each side before the coils and 4m of wire after the coils.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Homebrew loading coils have a measured inductance of 122.8 microhenries and a resistance of 0.3 ohms. <\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The best SWR has been obtained at 3.650 MHz, well within the 80m amateur radio band in this region. It is very near our 80m net frequency of 3.6 MHz. I am using 15m of RG213 cable as feedline.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The coils were wound on 1.5 inch PVC former with 18 SWG enamelled copper wire. Windings were spread over 11cm. Though the expected inductance was 118 microhenries, measured value was only about 67 microhenries. Maybe it was because of wider spacing between the wires when the coil was hand wound. Added extra turns as a second layer and by trial and error, obtained a final inductance of 122.8 microhenries. Major compromise with this antenna is the low height from the ground. Apex is at about 6m on a GI pipe and ends at about 3m from the ground. That is far below the quarter wavelength for 80m.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>After a lot of effort I have finally achieved SWR of 1.1 for my loaded coil dipole antenna for 80m. Currently it has 12.5m wire on each side before the coils and 4m of wire after the coils. Homebrew loading coils have a measured inductance of 122.8 microhenries and a resistance of 0.3 ohms. The [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":13320,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[7],"tags":[],"class_list":["post-13317","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-amateur-radio-ham-radio"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v27.8 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>Excellent SWR for my loaded coil 80m antenna! - Johnson&#039;s Techworld<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/johnsonfrancis.org\/techworld\/excellent-swr-for-my-loaded-coil-80m-antenna\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Excellent SWR for my loaded coil 80m antenna! - Johnson&#039;s Techworld\" \/>\n<meta property=\"og:description\" content=\"After a lot of effort I have finally achieved SWR of 1.1 for my loaded coil dipole antenna for 80m. Currently it has 12.5m wire on each side before the coils and 4m of wire after the coils. Homebrew loading coils have a measured inductance of 122.8 microhenries and a resistance of 0.3 ohms. 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Originally licensed as VU2JFP with Grade 1 license in 1985. Upgraded to Advanced Grade in 1988 and was allotted new callsign to VU2JO\",\"sameAs\":[\"https:\\\/\\\/johnsonfrancis.org\\\/techworld\",\"https:\\\/\\\/www.youtube.com\\\/@johnsonstechworld\\\/\"],\"url\":\"https:\\\/\\\/johnsonfrancis.org\\\/techworld\\\/author\\\/jf\\\/\"}]}<\/script>\n<!-- \/ Yoast SEO plugin. -->","yoast_head_json":{"title":"Excellent SWR for my loaded coil 80m antenna! - Johnson&#039;s Techworld","robots":{"index":"index","follow":"follow","max-snippet":"max-snippet:-1","max-image-preview":"max-image-preview:large","max-video-preview":"max-video-preview:-1"},"canonical":"https:\/\/johnsonfrancis.org\/techworld\/excellent-swr-for-my-loaded-coil-80m-antenna\/","og_locale":"en_US","og_type":"article","og_title":"Excellent SWR for my loaded coil 80m antenna! - Johnson&#039;s Techworld","og_description":"After a lot of effort I have finally achieved SWR of 1.1 for my loaded coil dipole antenna for 80m. 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