{"id":2548,"date":"2023-06-02T18:50:37","date_gmt":"2023-06-02T13:20:37","guid":{"rendered":"https:\/\/johnsonfrancis.org\/techworld\/?p=2548"},"modified":"2024-02-08T11:25:50","modified_gmt":"2024-02-08T05:55:50","slug":"what-is-grey-line-propagation-in-amateur-radio","status":"publish","type":"post","link":"https:\/\/johnsonfrancis.org\/techworld\/what-is-grey-line-propagation-in-amateur-radio\/","title":{"rendered":"What is Grey Line Propagation in Amateur Radio?"},"content":{"rendered":"<h2><span style=\"color: #008000;\">What is Grey Line Propagation in Amateur Radio?<\/span><\/h2>\n<p>Wiktionary definition of grey line is a transition line coinciding with twilight zone where a change in the propagation of radio waves is observed. Grey line propagation provides surprisingly long distance communications at dawn and dusk. I still remember how I used to work W-land (US) stations at dawn and dusk on CW using my homebrew setup on 40 m, nearly 4 decades back. I could never hear or work W-land at other times of the day on 40 and I did not have access to higher bands on my setup. That small time window corresponded to grey line propagation though I was not aware of it at that time. It is mentioned that grey line propagation occurs at frequencies below 10 MHz.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter wp-image-2553 size-full\" src=\"https:\/\/johnsonfrancis.org\/techworld\/wp-content\/uploads\/2023\/06\/What-is-Grey-Line-Propagation-in-Amateur-Radio.jpg\" alt=\"What is Grey Line Propagation in Amateur Radio\" width=\"1200\" height=\"729\" srcset=\"https:\/\/johnsonfrancis.org\/techworld\/wp-content\/uploads\/2023\/06\/What-is-Grey-Line-Propagation-in-Amateur-Radio.jpg 1200w, https:\/\/johnsonfrancis.org\/techworld\/wp-content\/uploads\/2023\/06\/What-is-Grey-Line-Propagation-in-Amateur-Radio-300x182.jpg 300w, https:\/\/johnsonfrancis.org\/techworld\/wp-content\/uploads\/2023\/06\/What-is-Grey-Line-Propagation-in-Amateur-Radio-1024x622.jpg 1024w, https:\/\/johnsonfrancis.org\/techworld\/wp-content\/uploads\/2023\/06\/What-is-Grey-Line-Propagation-in-Amateur-Radio-768x467.jpg 768w\" sizes=\"auto, (max-width: 1200px) 100vw, 1200px\" \/><\/p>\n<p>The D layer of the ionosphere which absorbs lower frequencies, fades at dusk as the illumination from the sun comes down at the Earths surface, and disappears at night. Ionization of the F layer is still better as it is at higher altitude, and gets illumination from the sun for a longer period. Moreover, as the air is thinner than D layer in the F layer, recombination of electrons with ions take longer period. For these reasons, F layer permits long distance communications at dawn and dusk. Grey line propagation is along the grey or twilight zone. That is how I was able to work W-land on 40 m during twilight, which is exactly on the other side of the globe for us!<\/p>\n<p>During sunrise, F layer gets ionized earlier than the D layer. So frequencies which get absorbed by D layer gets access to F layer during dawn and gets reflected for a longer distance, permitting DX communications. The grey line propagation does not apply to higher frequencies which does not get absorbed by the D layer of the ionosphere. That is why it is more likely to occur on 40 m than 20 m. It is mentioned that grey line propagation is most noticeable at the 80 m amateur radio band. During my days of activity on HF nearly 4 decades back, I could not work any DX on 80 m, possibly due to the limitations of my homebrew setup.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>What is Grey Line Propagation in Amateur Radio? Wiktionary definition of grey line is a transition line coinciding with twilight zone where a change in the propagation of radio waves is observed. Grey line propagation provides surprisingly long distance communications at dawn and dusk. I still remember how I used to work W-land (US) stations [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":2553,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[7],"tags":[],"class_list":["post-2548","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>What is Grey Line Propagation in Amateur Radio? - 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\/what-is-grey-line-propagation-in-amateur-radio\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"What is Grey Line Propagation in Amateur Radio? - Johnson&#039;s Techworld\" \/>\n<meta property=\"og:description\" content=\"What is Grey Line Propagation in Amateur Radio? Wiktionary definition of grey line is a transition line coinciding with twilight zone where a change in the propagation of radio waves is observed. Grey line propagation provides surprisingly long distance communications at dawn and dusk. 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