{"id":42227,"date":"2020-03-08T12:19:43","date_gmt":"2020-03-08T16:19:43","guid":{"rendered":"https:\/\/swling.com\/blog\/?p=42227"},"modified":"2020-03-08T12:20:13","modified_gmt":"2020-03-08T16:20:13","slug":"lets-solve-another-interval-signal-mystery","status":"publish","type":"post","link":"https:\/\/swling.com\/blog\/2020\/03\/lets-solve-another-interval-signal-mystery\/","title":{"rendered":"Let’s solve another interval signal mystery!"},"content":{"rendered":"

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

Last month, we published\u00a0a post<\/a>\u00a0asking\u00a0SWLing Readers<\/em> to help Brian (W9IND) identify an elusive interval signal. Turns out, the interval signal belonged to the Voice Mirror of the PTT Habana, Cuba station<\/a>.<\/p>\n

This month, SWLing Post<\/em> contributor, David Crawford is asking for help to ID another interval signal which likely belongs to a utility station. David writes:<\/p>\n

In follow-up to the La Habana utility mystery, here’s another one from the same era, 14985 kHz or thereabouts. Somewhere along the line I came to the conclusion that it might be El Salvador, but I don’t remember what led to that. The [recording embedded below] isn’t my own recording of it.
\n\"\"<\/a><\/p>\n

The tune is composed of individual DTMF tones, and when I was a bored youth I discovered that it could be played on an AT&T desk touch tone phone by pressing two keys at a time to remove the second tone. This one would repeat for hours at a time, interrupted by manually patched telephone calls.<\/p><\/blockquote>\nhttps:\/\/swling.com\/blog\/wp-content\/uploads\/2020\/03\/12_note_poly_tone_1976_one_minute.mp3<\/a><\/audio>\n

Readers: Can you positively ID this interval signal? If so, please comment<\/a>!<\/strong><\/p>\n","protected":false},"excerpt":{"rendered":"

Last month, we published\u00a0a post\u00a0asking\u00a0SWLing Readers to help Brian (W9IND) identify an elusive interval signal. Turns out, the interval signal belonged to the Voice Mirror of the PTT Habana, Cuba station. This month, SWLing Post contributor, David Crawford is asking for help to ID another interval signal which likely belongs to a utility station. David […]<\/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":[3,43],"tags":[8348,94,5448,1064,4082],"class_list":["post-42227","post","type-post","status-publish","format-standard","hentry","category-news","category-shortwave-radio","tag-david-crawford","tag-interval-signals","tag-mystery-signals","tag-radio-recordings","tag-shortwave-radio"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_shortlink":"https:\/\/wp.me\/pn3uc-aZ5","jetpack-related-posts":[{"id":42154,"url":"https:\/\/swling.com\/blog\/2020\/02\/mystery-solved-readers-identify-curious-interval-signal\/","url_meta":{"origin":42227,"position":0},"title":"Mystery Solved: Readers identify curious interval signal","author":"Thomas","date":"February 24, 2020","format":false,"excerpt":"Yesterday, we published a post asking SWLing Readers to help Brian (W9IND) identify an elusive interval signal (click here to read that post). We received dozens of replies--thank you so much! Many readers immediately identified the tune as some sort of utility station placeholder for Point To Point communications. Turns\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\/2020\/02\/PTT-Habana-Cuba-VErification.jpg?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2020\/02\/PTT-Habana-Cuba-VErification.jpg?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2020\/02\/PTT-Habana-Cuba-VErification.jpg?resize=525%2C300&ssl=1 1.5x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2020\/02\/PTT-Habana-Cuba-VErification.jpg?resize=700%2C400&ssl=1 2x"},"classes":[]},{"id":42461,"url":"https:\/\/swling.com\/blog\/2020\/03\/yet-another-mystery-utility-signal-to-solve\/","url_meta":{"origin":42227,"position":1},"title":"Yet another mystery utility signal to solve–!","author":"Thomas","date":"March 23, 2020","format":false,"excerpt":"Back by popular demand! On our quest to solve UNID utility signals, SWLing Post contributor David Crawford, is asking for help again to ID yet another interval signal. David writes: Here's yet another memorable utili-tune from the deep archives here, again not my recording, origin uncertain. This one has a\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\/2017\/06\/Pink-Vintage-Dial.jpg?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2017\/06\/Pink-Vintage-Dial.jpg?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2017\/06\/Pink-Vintage-Dial.jpg?resize=525%2C300&ssl=1 1.5x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2017\/06\/Pink-Vintage-Dial.jpg?resize=700%2C400&ssl=1 2x"},"classes":[]},{"id":42243,"url":"https:\/\/swling.com\/blog\/2020\/03\/dean-solves-second-interval-signal-mystery\/","url_meta":{"origin":42227,"position":2},"title":"Dean solves second interval signal mystery","author":"Thomas","date":"March 9, 2020","format":false,"excerpt":"In response to our second mystery interval signal challenge, SWLing Post contributor, Dean Bianco replies: Mystery solved! This is the \u201cinterval signal\u201d (more accurately, a placeholder with a musical station identifier) for the Compa\u00f1\u00eda Telef\u00f3nica Nacional de Espa\u00f1a (CTNW) from Madrid, Spain. They were a point-to-point HF radiotelephone terminal that\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\/2020\/03\/Compania-Telefonica-Nacional-de-Espana-642x1024.jpg?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2020\/03\/Compania-Telefonica-Nacional-de-Espana-642x1024.jpg?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2020\/03\/Compania-Telefonica-Nacional-de-Espana-642x1024.jpg?resize=525%2C300&ssl=1 1.5x"},"classes":[]},{"id":42146,"url":"https:\/\/swling.com\/blog\/2020\/02\/help-brian-identify-this-1970s-era-interval-signal\/","url_meta":{"origin":42227,"position":3},"title":"Help Brian identify this 1970s era interval signal","author":"Thomas","date":"February 23, 2020","format":false,"excerpt":"[Mystery solved! Click here to read the update.] Many thanks to SWLing Post contributor, Brian (W9IND), who writes: I want to thank you for stirring a memory that I never thought I\u2019d relive \u2013 even though it still doesn\u2019t solve the mystery of what the heck I was listening to\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\/09\/SX-99-Dial-Nar.jpg?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2015\/09\/SX-99-Dial-Nar.jpg?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2015\/09\/SX-99-Dial-Nar.jpg?resize=525%2C300&ssl=1 1.5x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2015\/09\/SX-99-Dial-Nar.jpg?resize=700%2C400&ssl=1 2x"},"classes":[]},{"id":60019,"url":"https:\/\/swling.com\/blog\/2024\/06\/can-you-help-dan-identify-this-mystery-interval-signal\/","url_meta":{"origin":42227,"position":4},"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":221,"url":"https:\/\/swling.com\/blog\/2011\/07\/between-broadcasts-exploring-interval-signals\/","url_meta":{"origin":42227,"position":5},"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":[]}],"jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/swling.com\/blog\/wp-json\/wp\/v2\/posts\/42227","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=42227"}],"version-history":[{"count":0,"href":"https:\/\/swling.com\/blog\/wp-json\/wp\/v2\/posts\/42227\/revisions"}],"wp:attachment":[{"href":"https:\/\/swling.com\/blog\/wp-json\/wp\/v2\/media?parent=42227"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/swling.com\/blog\/wp-json\/wp\/v2\/categories?post=42227"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/swling.com\/blog\/wp-json\/wp\/v2\/tags?post=42227"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}