{"id":23031,"date":"2016-12-31T08:02:48","date_gmt":"2016-12-31T12:02:48","guid":{"rendered":"http:\/\/swling.com\/blog\/?p=23031"},"modified":"2016-12-31T08:02:48","modified_gmt":"2016-12-31T12:02:48","slug":"looking-at-hf-oth-radar","status":"publish","type":"post","link":"https:\/\/swling.com\/blog\/2016\/12\/looking-at-hf-oth-radar\/","title":{"rendered":"Looking at HF OTH RADAR"},"content":{"rendered":"

\"\"<\/a><\/p>\n

Many thanks to SWLing Post<\/em> contributor, Trevor, who shares this link to a blog post from\u00a0Daniel Estevez<\/a>\u00a0describing the characteristics of HF OTH RADAR:<\/p>\n

Most amateur operators are familiar with over-the-horizon radars<\/a> in the HF bands. They sometimes pop up in the Amateur bands<\/a>, rendering several tens of kilohertzs unusable. Inspired by Balint Seeber’s talk in GRCon16<\/a>, I’ve decided to learn more about radars. Here I look at a typical OTH radar, presumably of Russian origin. It was recorded at my station around 20:00UTC on 8 December at a frequency around 6860kHz. This radar sometimes appears inside the 40m Amateur band as well.<\/p>\n

Above this post you can see a waterfall plot of the radar signal. It’s the wide red signal. It is 15kHz wide and pretty strong, but severely affected by frequency-selective fading. Looking at the IQ recording in Audacity, it is clear that the radar uses pulses with a 50Hz repetition rate. This explains the characteristic sound of this radar when received with a conventional SSB radio. It sounds similar to AC hum (here in Europe, of course).<\/p><\/blockquote>\n

Continue reading on Daniel’s blog…<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

Many thanks to SWLing Post contributor, Trevor, who shares this link to a blog post from\u00a0Daniel Estevez\u00a0describing the characteristics of HF OTH RADAR: Most amateur operators are familiar with over-the-horizon radars in the HF bands. They sometimes pop up in the Amateur bands, rendering several tens of kilohertzs unusable. Inspired by Balint Seeber’s talk in […]<\/p>\n","protected":false},"author":15,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"jetpack_post_was_ever_published":false,"_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":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":true,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2}},"categories":[1114,545,3,43],"tags":[5769,4368,5768,5770],"class_list":["post-23031","post","type-post","status-publish","format-standard","hentry","category-digital-modes","category-ham-radio","category-news","category-shortwave-radio","tag-daniel-estevez","tag-oth","tag-oth-radar","tag-trevor"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_shortlink":"https:\/\/wp.me\/pn3uc-5Zt","jetpack-related-posts":[{"id":40622,"url":"https:\/\/swling.com\/blog\/2019\/11\/contayner-over-the-horizon-radar-site-polluting-the-hf-spectrum\/","url_meta":{"origin":23031,"position":0},"title":"Contayner Over-The-Horizon Radar site polluting the HF spectrum","author":"Thomas","date":"November 14, 2019","format":false,"excerpt":"Many thanks to\u00a0SWLing Post\u00a0contributor,\u00a0Paul Evans, who writes: The news from IARU Region 1 observer reports is all over the radio internet (including news sites and other blogs), but the extent of this [Russian] OTHR is grim. [Click here to read a recent ARRL News post.] It is also entering service\u2026","rel":"","context":"In "Ham Radio"","block_context":{"text":"Ham Radio","link":"https:\/\/swling.com\/blog\/category\/ham-radio\/"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2019\/11\/Contayner-OTH-RADAR-Spectrum-Display-Waterfall.jpg?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2019\/11\/Contayner-OTH-RADAR-Spectrum-Display-Waterfall.jpg?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2019\/11\/Contayner-OTH-RADAR-Spectrum-Display-Waterfall.jpg?resize=525%2C300&ssl=1 1.5x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2019\/11\/Contayner-OTH-RADAR-Spectrum-Display-Waterfall.jpg?resize=700%2C400&ssl=1 2x"},"classes":[]},{"id":15422,"url":"https:\/\/swling.com\/blog\/2015\/11\/hearing-ghadir-irans-sepehr-phased-radar-system\/","url_meta":{"origin":23031,"position":1},"title":"Hearing Ghadir: Iran\u2019s Sepehr Phased Radar System","author":"Thomas","date":"November 3, 2015","format":false,"excerpt":"In response to Andrea's UVB-76 recording, SWLing Post contributor, Mehdi, comments: Thomas, another signal which may sound mysterious: Iran\u2019s OTH Radar, named \u201cGhadir\u201d; part of Iran\u2019s Sepehr Phased Radar System. They\u2019d polluted the 10-meter band [in the past]; now they transmit on 26MHZ. (See spectrum in screen capture above.) Sound:\u2026","rel":"","context":"In "Digital Modes"","block_context":{"text":"Digital Modes","link":"https:\/\/swling.com\/blog\/category\/digital-modes\/"},"img":{"alt_text":"Mehdi-Waterfall","src":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2015\/11\/Mehdi-Waterfall-1024x551.jpg?resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2015\/11\/Mehdi-Waterfall-1024x551.jpg?resize=350%2C200 1x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2015\/11\/Mehdi-Waterfall-1024x551.jpg?resize=525%2C300 1.5x"},"classes":[]},{"id":49359,"url":"https:\/\/swling.com\/blog\/2021\/06\/can-you-id-these-hf-transmissions\/","url_meta":{"origin":23031,"position":2},"title":"Can you ID these HF transmissions?","author":"Thomas","date":"June 23, 2021","format":false,"excerpt":"Many thanks to SWLing Post contributor, Carlos Latuff, who shares the following video of sounds he heard on HF. Carlos adds, \"Are we in the Twilight Zone or Lost in Space? They sound like effects from a 60's\/70's sci-fi movie!\" https:\/\/youtu.be\/mSKPgKCvMNI Those sounds are wild! The stuff of Star Wars.\u2026","rel":"","context":"In "News"","block_context":{"text":"News","link":"https:\/\/swling.com\/blog\/category\/news\/"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2018\/03\/XHDATA-D-808-Right-Side.jpg?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2018\/03\/XHDATA-D-808-Right-Side.jpg?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2018\/03\/XHDATA-D-808-Right-Side.jpg?resize=525%2C300&ssl=1 1.5x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2018\/03\/XHDATA-D-808-Right-Side.jpg?resize=700%2C400&ssl=1 2x"},"classes":[]},{"id":60255,"url":"https:\/\/swling.com\/blog\/2024\/07\/radio-waves-who-will-pay-ham-radio-culture-oth-support-night-of-nights-and-100-years-of-radio\/","url_meta":{"origin":23031,"position":3},"title":"Radio Waves: Who Will Pay, Ham Radio Culture, OTH Support, CarnationFM, Night of Nights, and 100 Years of Radio","author":"Thomas","date":"July 25, 2024","format":false,"excerpt":"Radio Waves:\u00a0 Stories Making Waves in the World of Radio Welcome to the\u00a0SWLing Post\u2019s Radio Waves, a collection of links to interesting stories making waves in the world of radio.\u00a0Enjoy! Many thanks to SWLing Post contributors Richard Cuff, Dennis Dura, David Korchin, Roger Fitzharris, David Iurescia, and NT for the\u2026","rel":"","context":"In "Broadcasters"","block_context":{"text":"Broadcasters","link":"https:\/\/swling.com\/blog\/category\/broadcasters\/"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2018\/10\/Soviet-Radio-Dial-e1539517556232.jpg?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2018\/10\/Soviet-Radio-Dial-e1539517556232.jpg?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2018\/10\/Soviet-Radio-Dial-e1539517556232.jpg?resize=525%2C300&ssl=1 1.5x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2018\/10\/Soviet-Radio-Dial-e1539517556232.jpg?resize=700%2C400&ssl=1 2x"},"classes":[]},{"id":62989,"url":"https:\/\/swling.com\/blog\/2025\/05\/strange-interference-near-13860-khz-mario-tracks-it-to-kaliningrad\/","url_meta":{"origin":23031,"position":4},"title":"Strange Interference Near 13860 kHz: Mario Tracks It to Kaliningrad","author":"Thomas","date":"May 24, 2025","format":false,"excerpt":"Many thanks to SWLing Post contributor, Mario, who writes: Dear Thomas, It has been about two or three days since it was impossible for me to hear Radio Romania Int in Spanish (1900 UTC) from my home, at Zaragoza. A strange interference appeared close to my favourite SW station (13860).\u2026","rel":"","context":"In "News"","block_context":{"text":"News","link":"https:\/\/swling.com\/blog\/category\/news\/"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2025\/05\/image.png?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2025\/05\/image.png?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2025\/05\/image.png?resize=525%2C300&ssl=1 1.5x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2025\/05\/image.png?resize=700%2C400&ssl=1 2x"},"classes":[]},{"id":32719,"url":"https:\/\/swling.com\/blog\/2018\/06\/skov-notes-possible-role-of-amateur-radio-tech-with-mars-oth-communications\/","url_meta":{"origin":23031,"position":5},"title":"Skov notes possible role of amateur radio tech with Mars OTH communications","author":"Thomas","date":"June 8, 2018","format":false,"excerpt":"(Source: Southgate ARC) Over-the-horizon communication on Mars ARRL highlights a post by The Space Weather Woman,\u00a0Dr. Tamitha Skov, that notes the role amateur radio technology could play in over-the-horizon radio communications on Mars I am still smiling at the huge response I got to a post I put up on\u2026","rel":"","context":"In "News"","block_context":{"text":"News","link":"https:\/\/swling.com\/blog\/category\/news\/"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2018\/06\/mars_pathfinder_20_years.jpg?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2018\/06\/mars_pathfinder_20_years.jpg?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2018\/06\/mars_pathfinder_20_years.jpg?resize=525%2C300&ssl=1 1.5x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2018\/06\/mars_pathfinder_20_years.jpg?resize=700%2C400&ssl=1 2x"},"classes":[]}],"jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/swling.com\/blog\/wp-json\/wp\/v2\/posts\/23031","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/swling.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/swling.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/swling.com\/blog\/wp-json\/wp\/v2\/users\/15"}],"replies":[{"embeddable":true,"href":"https:\/\/swling.com\/blog\/wp-json\/wp\/v2\/comments?post=23031"}],"version-history":[{"count":0,"href":"https:\/\/swling.com\/blog\/wp-json\/wp\/v2\/posts\/23031\/revisions"}],"wp:attachment":[{"href":"https:\/\/swling.com\/blog\/wp-json\/wp\/v2\/media?parent=23031"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/swling.com\/blog\/wp-json\/wp\/v2\/categories?post=23031"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/swling.com\/blog\/wp-json\/wp\/v2\/tags?post=23031"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}