{"id":64980,"date":"2025-12-21T08:20:00","date_gmt":"2025-12-21T12:20:00","guid":{"rendered":"https:\/\/swling.com\/blog\/?p=64980"},"modified":"2025-12-22T07:28:39","modified_gmt":"2025-12-22T11:28:39","slug":"bobs-radio-corner-industrial-scientific-and-medical-ism-bands","status":"publish","type":"post","link":"https:\/\/swling.com\/blog\/2025\/12\/bobs-radio-corner-industrial-scientific-and-medical-ism-bands\/","title":{"rendered":"Bob’s Radio Corner: Industrial, Scientific, and Medical (ISM) Bands"},"content":{"rendered":"

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

Industrial, Scientific, and Medical (ISM) Bands<\/h1>\n

Noted by Bob Colegrove<\/strong><\/p>\n

This is not the sort of thing you might consider typical DX.\u00a0 One reporter traced a signal like the one I describe here to the innocuous utility box at the corner of his lot.\u00a0 No, it is not noise.\u00a0 It is an RF signal, essentially a shortwave station.<\/p>\n

With the dearth of stations on the international shortwave bands, my attention often turns to the vast swaths of frequencies in between.\u00a0 These are still commonly referred to as \u201cutility\u201d bands, and were once themselves filled with industrial, marine, aviation, and military signals using all manner of transmission modes.\u00a0 Like the international shortwave bands, they are now mostly intergalactic space open to an occasional user.<\/p>\n

Among these are the Industrial, Scientific, and Medical (ISM) Bands.\u00a0 The ISM bands are defined by the ITU Radio Regulations.\u00a0 Individual countries use the bands in different ways. \u00a0 The table below shows the ISM bands within the shortwave spectrum.\u00a0 Besides these, there are ISM bands extending up through the gigahertz range.<\/p>\n\n\n\n\n\n\n\n
Frequency<\/strong><\/td>\nBand<\/strong>
\nWidth<\/strong><\/td>\n<\/tr>\n
Low<\/td>\nHigh<\/td>\nCenter<\/td>\n<\/tr>\n
6.765 MHz<\/td>\n6.795 MHz<\/td>\n6.78 MHz<\/td>\n30 kHz<\/td>\n<\/tr>\n
13.553 MHz<\/td>\n13.567 MHz<\/td>\n13.56 MHz<\/td>\n14 kHz<\/td>\n<\/tr>\n
26.957 MHz<\/td>\n27.283 MHz<\/td>\n27.12 MHz<\/td>\n326 kHz<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

Unlicensed operations are typically permitted in these bands; therefore, communication devices using the ISM bands must tolerate interference from ISM equipment.\u00a0 Examples of devices that may use ISM frequencies include common household appliances such as microwave ovens, cordless phones, Bluetooth devices, garage door openers, and wireless computer networks.<\/p>\n

But more prevalent signals reaching the radio are identified as coming from locally positioned telecom company equipment such as those of Fios or Xfinity.\u00a0 Several years ago, both providers in my area switched to fiber optic distribution, which does not radiate RF.\u00a0 Thus, the source of my signals remains a mystery.<\/p>\n

My attention was drawn recently to a very strong continuous wave (CW) signal operating on 6780 kHz.\u00a0 Further tuning turned up progressively weaker signals on 13560 kHz (2nd harmonic) and 27120 kHz (4th harmonic).\u00a0 Note that these frequencies are squarely in the center of each ISM Band.\u00a0 A signal was also heard on 20340 kHz (3rd harmonic), which was not in any ISM band.<\/p>\n

Poking around the Internet, I found that others had similar experiences in recent years.\u00a0 As expected, the signal I received did not provide any identification during my monitoring.\u00a0 As stated, transmissions were continuous wave and pulsed at 1-second intervals much like a time signal.\u00a0 At irregular intervals, there would be a skip beat followed by a longer beep.\u00a0 After long intervals, the 1-second pulses would be replaced by a steady continuous wave lasting a couple of minutes, then return to the 1-second time-pip pattern.\u00a0 The signal remains on throughout the day and night.<\/p>\n

The signal was tuned as any other CW station by setting the radio to either USB or LSB and tuning slightly down or up from the carrier.\u00a0 Note in the recording that there are not always the same number of time-pips in each set, and that the longer beep between sets can differ in length.\u00a0 Perhaps this is some sort of data encoding.<\/p>\n

Besides my own reception in Central Maryland, a weak \u201ctime signal\u201d could be heard at the WEBSDR site in Central Pennsylvania (http:\/\/k3fef.com:8901<\/a>).\u00a0 There was a steady CW signal at 6780 kHz from the U. Twente WEBSDR site in the Netherlands, possibly indicating another type of ISM application.<\/p>\n

What\u2019s in your ISM Band?\u00a0 You may or may not hear a similar signal at your location.\u00a0 Let us know.<\/p>\n","protected":false},"excerpt":{"rendered":"

Industrial, Scientific, and Medical (ISM) Bands Noted by Bob Colegrove This is not the sort of thing you might consider typical DX.\u00a0 One reporter traced a signal like the one I describe here to the innocuous utility box at the corner of his lot.\u00a0 No, it is not noise.\u00a0 It is an RF signal, essentially […]<\/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":[3,746,43,9589],"tags":[7988,11003,11002,34],"class_list":["post-64980","post","type-post","status-publish","format-standard","hentry","category-news","category-recordings","category-shortwave-radio","category-utility","tag-bob-colegrove","tag-industrial-scientific-and-medical-bands","tag-ism-band","tag-shortwave"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_shortlink":"https:\/\/wp.me\/pn3uc-gU4","jetpack-related-posts":[{"id":64316,"url":"https:\/\/swling.com\/blog\/2025\/10\/bobs-radio-corner-shortwave-multiplex\/","url_meta":{"origin":64980,"position":0},"title":"Bob’s Radio Corner: Shortwave Multiplex?","author":"Thomas","date":"October 19, 2025","format":false,"excerpt":"Reported by Bob Colegrove Incurable DXers are always looking for new challenges.\u00a0 So it was, I recently did some scanning between 42 and 45 meters (~6600 to 7000 kHz).\u00a0 Trenton Military on 6754 kHz and the MARS net on 6913 kHz are regulars here, as are a selection of pirates\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\/10\/Fig.-1.jpg?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2025\/10\/Fig.-1.jpg?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2025\/10\/Fig.-1.jpg?resize=525%2C300&ssl=1 1.5x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2025\/10\/Fig.-1.jpg?resize=700%2C400&ssl=1 2x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2025\/10\/Fig.-1.jpg?resize=1050%2C600&ssl=1 3x"},"classes":[]},{"id":58339,"url":"https:\/\/swling.com\/blog\/2023\/12\/patrizio-seeks-information-about-mystery-signals-hes-discovering-across-the-hf-bands\/","url_meta":{"origin":64980,"position":1},"title":"Patrizio seeks information about mystery signals he’s discovering across the HF bands","author":"Thomas","date":"December 4, 2023","format":false,"excerpt":"Many thanks to SWLing Post contributor, Patrizio Cardelli, who has discovered some interesting signals on the HF bands and is seeking information about them. A little background: Patrizio asked me about these signals a few weeks ago and based on a quick glance at the spectrum and waterfall images I\u2026","rel":"","context":"In "Digital Modes"","block_context":{"text":"Digital Modes","link":"https:\/\/swling.com\/blog\/category\/digital-modes\/"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2023\/12\/Spectrum-1.jpeg?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2023\/12\/Spectrum-1.jpeg?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2023\/12\/Spectrum-1.jpeg?resize=525%2C300&ssl=1 1.5x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2023\/12\/Spectrum-1.jpeg?resize=700%2C400&ssl=1 2x"},"classes":[]},{"id":33395,"url":"https:\/\/swling.com\/blog\/2018\/08\/dave-reviews-the-icom-ic-r30-handheld-wide-band-receiver\/","url_meta":{"origin":64980,"position":2},"title":"Dave reviews the Icom IC-R30 Handheld Wide Band Receiver","author":"Thomas","date":"August 4, 2018","format":false,"excerpt":"Many thanks to SWLing Post contributor, Dave Zantow (N9EWO), who notes that he has published his comprehensive review of the Icom IC-R30 handheld wideband receiver. Click here to check out Dave's review. Based on Dave's evaluation, it sounds like this is one of the better wideband radios, although like similar\u2026","rel":"","context":"In "New Products"","block_context":{"text":"New Products","link":"https:\/\/swling.com\/blog\/category\/new-products\/"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2018\/05\/2018-Hamvention-Photos-Sunday-6-of-11-768x1024.jpg?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2018\/05\/2018-Hamvention-Photos-Sunday-6-of-11-768x1024.jpg?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2018\/05\/2018-Hamvention-Photos-Sunday-6-of-11-768x1024.jpg?resize=525%2C300&ssl=1 1.5x"},"classes":[]},{"id":42243,"url":"https:\/\/swling.com\/blog\/2020\/03\/dean-solves-second-interval-signal-mystery\/","url_meta":{"origin":64980,"position":3},"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":27332,"url":"https:\/\/swling.com\/blog\/2017\/07\/guest-post-old-school-infrared-wireless-headphones\/","url_meta":{"origin":64980,"position":4},"title":"Guest Post: Old School Infrared Wireless Headphones","author":"Thomas","date":"July 26, 2017","format":false,"excerpt":"Many thanks to SWLing Post contributor,\u00a0Mario Filippi (N2HUN), who shares the following guest post: Old School (Infrared) Wireless Headphones by\u00a0Mario Filippi (N2HUN) Have you ever mindlessly walked away from your TV with headphones\/ear buds still tethered, causing all sorts of havoc? Been there, done that hi hi! Let\u2019s face it;\u2026","rel":"","context":"In "Accessories"","block_context":{"text":"Accessories","link":"https:\/\/swling.com\/blog\/category\/accessories\/"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2017\/07\/Sony-cordless-headphones-e1501068828925.jpg?resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2017\/07\/Sony-cordless-headphones-e1501068828925.jpg?resize=350%2C200 1x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2017\/07\/Sony-cordless-headphones-e1501068828925.jpg?resize=525%2C300 1.5x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2017\/07\/Sony-cordless-headphones-e1501068828925.jpg?resize=700%2C400 2x"},"classes":[]},{"id":63114,"url":"https:\/\/swling.com\/blog\/2025\/06\/bobs-radio-corner-tuning-single-letter-cluster-beacons\/","url_meta":{"origin":64980,"position":5},"title":"Bob’s Radio Corner: Tuning Single-Letter Cluster Beacons","author":"Thomas","date":"June 8, 2025","format":false,"excerpt":"Tuning Single-Letter Cluster Beacons by Bob Colegrove Part of the allure of shortwave listening for me has always been vicarious visits to \u201cthose faraway places with the strange-soundin' names.\u201d\u00a0 After one has logged several big-time broadcasters, one begins to look for new challenges.\u00a0 Most of the so-called \u201cutility\u201d content which\u2026","rel":"","context":"In "Beacons"","block_context":{"text":"Beacons","link":"https:\/\/swling.com\/blog\/category\/beacons\/"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2025\/06\/Table-2-LSB-DESKTOP-LGN2IGT.jpg?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2025\/06\/Table-2-LSB-DESKTOP-LGN2IGT.jpg?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2025\/06\/Table-2-LSB-DESKTOP-LGN2IGT.jpg?resize=525%2C300&ssl=1 1.5x"},"classes":[]}],"jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/swling.com\/blog\/wp-json\/wp\/v2\/posts\/64980","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=64980"}],"version-history":[{"count":5,"href":"https:\/\/swling.com\/blog\/wp-json\/wp\/v2\/posts\/64980\/revisions"}],"predecessor-version":[{"id":64994,"href":"https:\/\/swling.com\/blog\/wp-json\/wp\/v2\/posts\/64980\/revisions\/64994"}],"wp:attachment":[{"href":"https:\/\/swling.com\/blog\/wp-json\/wp\/v2\/media?parent=64980"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/swling.com\/blog\/wp-json\/wp\/v2\/categories?post=64980"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/swling.com\/blog\/wp-json\/wp\/v2\/tags?post=64980"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}