{"id":65726,"date":"2026-04-03T07:23:31","date_gmt":"2026-04-03T11:23:31","guid":{"rendered":"https:\/\/swling.com\/blog\/?p=65726"},"modified":"2026-04-03T07:23:31","modified_gmt":"2026-04-03T11:23:31","slug":"bbc-interval-signals-then-and-now","status":"publish","type":"post","link":"https:\/\/swling.com\/blog\/2026\/04\/bbc-interval-signals-then-and-now\/","title":{"rendered":"BBC Interval Signals \u2013 Then and Now"},"content":{"rendered":"

\"\"<\/a>by Dan Greenall<\/strong><\/p>\n

A half century ago, the BBC World Service used a number of different interval signals. \u00a0 A few minutes prior to the start of a broadcast, a recognizable, often repeating tune would be played that would enable listeners to more easily locate the BBC in a crowded band on a typical analog receiver.<\/p>\n

\"\"<\/a>A peek into the 1975 World Radio TV Handbook notes a few of these.\u00a0 There was the Morse signal V (as in, V for Victory), primarily used for broadcasts to Europe.\u00a0 It was also identified as 4 notes tuned B-B-B-E, and an example can be found on Jerry Johnston\u2019s page of shortwave interval signals:<\/p>\n

https:\/\/www.iaswww.com\/swmp3\/intervalsignals\/simple_is.php<\/a><\/p>\n

Next, a version of the children\u2019s nursery rhyme \u201cOranges and Lemons\u201d was used during the 1970\u2019s, and I\u00a0 have managed to save a recording of it here:<\/p>\n

https:\/\/archive.org\/details\/oranges-and-lemons_202510<\/a><\/p>\nhttps:\/\/archive.org\/download\/oranges-and-lemons_202510\/oranges%20and%20lemons.m4a<\/a><\/audio>\n

Then, there were the three notes \u201cB-B-C\u201d in tonic scale.\u00a0 This was assigned to the World Service for Africa and other services.<\/p>\n

Finally, though not listed in this edition of the handbook, was the highly recognizable sound of the Bow Bells. This one came into common use during World War Two when it was broadcast as a symbol of hope for the people of Europe.\u00a0 At least one source states that the original recording was made in 1926, now 100 years ago.\u00a0 Many recordings of the Bow Bells interval signal can be found online via YouTube.<\/p>\n

More recently, many of the BBC World Service broadcasts seem to start up very abruptly.\u00a0 An open carrier appears on the frequency to be used only minutes, or even seconds, before the program (already in progress) begins. One example is noted in this recording made on February 5, 2026, just prior to 2200 UTC sign-on, on a frequency of 11645 kHz.<\/p>\nhttps:\/\/swling.com\/blog\/wp-content\/uploads\/2026\/04\/BBC-abrupt-start-hyd.twrmon.net_2026-02-05T21_59_17Z_11645.00_am.mp3<\/a><\/audio>\n

However, two of the above-mentioned tuning signals appear to still be occasionally in use.\u00a0 The three-note B-B-C was observed on March 4, 2026, at 0028 UTC on 7445 kHz. This recording was made through a Kiwi SDR on the island of Cyprus.<\/p>\nhttps:\/\/swling.com\/blog\/wp-content\/uploads\/2026\/04\/BBC-3-note-IS-sdr.cyhams.org_2026-03-04T00_28_25Z_7445.00_am.mp3<\/a><\/audio>\n

I also logged them using their Bow Bells interval signal on December 28, 2025 at 2358 UTC on 6155 kHz while listening on a Kiwi SDR in Thailand.\u00a0 Here is how they sounded then.<\/p>\nhttps:\/\/swling.com\/blog\/wp-content\/uploads\/2026\/04\/BBC-IS-bowbells-la6lukiwisdrth.ddns_.net_2025-12-28T23_58_48Z_6155.00_am.mp3<\/a><\/audio>\n

As well, SRAA reporter Paul Walker noted reception of the Bow Bells back in September 2025 on 9410 kHz.\u00a0 Follow this link to his report:<\/p>\n

https:\/\/shortwavearchive.com\/archive\/bbc-world-service-carrier-and-interval-signal-september-19-20-and-25-2025?rq=paul%20walker<\/a><\/p>\n

I would be curious if other listeners have heard any of these interval signals recently preceding \u00a0 BBC World Service broadcasts.<\/p>\n","protected":false},"excerpt":{"rendered":"

by Dan Greenall A half century ago, the BBC World Service used a number of different interval signals. \u00a0 A few minutes prior to the start of a broadcast, a recognizable, often repeating tune would be played that would enable listeners to more easily locate the BBC in a crowded band on a typical analog […]<\/p>\n","protected":false},"author":15,"featured_media":0,"comment_status":"open","ping_status":"closed","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":[3,305,288,746,43],"tags":[327,11078,10271,94,4094,4091,4082],"class_list":["post-65726","post","type-post","status-publish","format-standard","hentry","category-news","category-nostalgia","category-radio-history","category-recordings","category-shortwave-radio","tag-bbc-world-service","tag-bbc-world-service-interval-signals","tag-dan-greenall","tag-interval-signals","tag-nostalgia","tag-radio-history","tag-shortwave-radio"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_shortlink":"https:\/\/wp.me\/pn3uc-h66","jetpack-related-posts":[{"id":60019,"url":"https:\/\/swling.com\/blog\/2024\/06\/can-you-help-dan-identify-this-mystery-interval-signal\/","url_meta":{"origin":65726,"position":0},"title":"Can you help Dan identify this mystery interval signal?","author":"Thomas","date":"June 17, 2024","format":false,"excerpt":"Many thanks to Dan Greenall, one of our dedicated Shortwave Radio Audio Archive contributors, who writes: Hi Thomas I was going over a few of my old cassettes today and discovered what seems to be an interval signal, but I cannot seem to place it. Recording: Unfortunately, all I can\u2026","rel":"","context":"In "News"","block_context":{"text":"News","link":"https:\/\/swling.com\/blog\/category\/news\/"},"img":{"alt_text":"Photo by Sai Harish on Unsplash","src":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2024\/06\/Casette-Tape-1.jpeg?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2024\/06\/Casette-Tape-1.jpeg?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2024\/06\/Casette-Tape-1.jpeg?resize=525%2C300&ssl=1 1.5x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2024\/06\/Casette-Tape-1.jpeg?resize=700%2C400&ssl=1 2x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2024\/06\/Casette-Tape-1.jpeg?resize=1050%2C600&ssl=1 3x"},"classes":[]},{"id":62314,"url":"https:\/\/swling.com\/blog\/2025\/03\/finding-the-kookaburra-on-shortwave-past-and-present\/","url_meta":{"origin":65726,"position":1},"title":"Finding the Kookaburra on Shortwave\u2014Past and Present","author":"Thomas","date":"March 9, 2025","format":false,"excerpt":"Many thanks to SWLing Post contributor, Dan Greenall, who writes: Hi Thomas I still have warm memories of tuning into Radio Australia on 9580 kHz at sunrise during my early days of shortwave listening. They would sign on with their Waltzing Matilda interval signal and the sound of the kookaburra\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\/03\/Photo-by-Matthew-Willimott-1.jpeg?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2025\/03\/Photo-by-Matthew-Willimott-1.jpeg?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2025\/03\/Photo-by-Matthew-Willimott-1.jpeg?resize=525%2C300&ssl=1 1.5x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2025\/03\/Photo-by-Matthew-Willimott-1.jpeg?resize=700%2C400&ssl=1 2x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2025\/03\/Photo-by-Matthew-Willimott-1.jpeg?resize=1050%2C600&ssl=1 3x"},"classes":[]},{"id":57327,"url":"https:\/\/swling.com\/blog\/2023\/07\/radio-botswana-barnyard-sounds-mystery\/","url_meta":{"origin":65726,"position":2},"title":"Radio Botswana barnyard sounds mystery","author":"Thomas","date":"July 23, 2023","format":false,"excerpt":"Many thanks to SWLing Post and SRAA contributor, Dan Greenall, who shares the following off-air shortwave radio recording and writes: In all of the recordings of Radio Botswana\u2019s famous barnyard interval signal I can find, the barnyard sounds are accompanied by the sound of cowbells. There is usually a rooster\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\/2015\/08\/HalliDial.jpg?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2015\/08\/HalliDial.jpg?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2015\/08\/HalliDial.jpg?resize=525%2C300&ssl=1 1.5x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2015\/08\/HalliDial.jpg?resize=700%2C400&ssl=1 2x"},"classes":[]},{"id":63280,"url":"https:\/\/swling.com\/blog\/2025\/06\/feba-then-and-now\/","url_meta":{"origin":65726,"position":3},"title":"FEBA, Then and Now","author":"Thomas","date":"June 27, 2025","format":false,"excerpt":"Many thanks to SWLing Post contributor, Dan Greenall, who writes: It seems that fewer shortwave broadcasters utilize an interval signal these days. However, of the ones that do, at least a couple seem to have stood the test of time, going back over 50 years. The bellbird from Radio New\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\/10\/Zenith-Transoceanic-R-7000-2-angle-e1540388449299.jpg?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2018\/10\/Zenith-Transoceanic-R-7000-2-angle-e1540388449299.jpg?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2018\/10\/Zenith-Transoceanic-R-7000-2-angle-e1540388449299.jpg?resize=525%2C300&ssl=1 1.5x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2018\/10\/Zenith-Transoceanic-R-7000-2-angle-e1540388449299.jpg?resize=700%2C400&ssl=1 2x"},"classes":[]},{"id":221,"url":"https:\/\/swling.com\/blog\/2011\/07\/between-broadcasts-exploring-interval-signals\/","url_meta":{"origin":65726,"position":4},"title":"Between Broadcasts-Exploring Interval Signals","author":"Thomas","date":"July 7, 2011","format":false,"excerpt":"Lately, I've been listening to a plethora of shortwave broadcasts as I'm about to review several new radios. I've noted so many great interval signals that are still in use.\u00a0The following is a reprise of a previous post--from over two years ago--about interval signals. If you've never heard of interval\u2026","rel":"","context":"In "Articles"","block_context":{"text":"Articles","link":"https:\/\/swling.com\/blog\/category\/articles\/"},"img":{"alt_text":"Analog Radio Dial","src":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/\/2009\/05\/swdial.jpg?resize=350%2C200","width":350,"height":200},"classes":[]},{"id":18852,"url":"https:\/\/swling.com\/blog\/2016\/05\/from-the-bbc-archives-the-first-21-years-of-the-world-service\/","url_meta":{"origin":65726,"position":5},"title":"From the BBC Archives: The first 21 years of the World Service","author":"Thomas","date":"May 18, 2016","format":false,"excerpt":"Many thanks to SWLing Post contributor,\u00a0Andrea Borgnino, who shares a link to the excellent archived radio documentary,\u00a0The first 21 years of the World Service, via the\u00a0BBC World Service's\u00a0online audio archives. The recording\/broadcast dates from\u00a0December, 18 1953.\u00a0Here's the description of the recording: The first 21 years of the World Service: how\u2026","rel":"","context":"In "Broadcasters"","block_context":{"text":"Broadcasters","link":"https:\/\/swling.com\/blog\/category\/broadcasters\/"},"img":{"alt_text":"BBC-AT-WAR","src":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2015\/06\/BBC-AT-WAR.jpg?resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2015\/06\/BBC-AT-WAR.jpg?resize=350%2C200 1x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2015\/06\/BBC-AT-WAR.jpg?resize=525%2C300 1.5x"},"classes":[]}],"jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/swling.com\/blog\/wp-json\/wp\/v2\/posts\/65726","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=65726"}],"version-history":[{"count":1,"href":"https:\/\/swling.com\/blog\/wp-json\/wp\/v2\/posts\/65726\/revisions"}],"predecessor-version":[{"id":65733,"href":"https:\/\/swling.com\/blog\/wp-json\/wp\/v2\/posts\/65726\/revisions\/65733"}],"wp:attachment":[{"href":"https:\/\/swling.com\/blog\/wp-json\/wp\/v2\/media?parent=65726"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/swling.com\/blog\/wp-json\/wp\/v2\/categories?post=65726"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/swling.com\/blog\/wp-json\/wp\/v2\/tags?post=65726"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}