{"id":48268,"date":"2021-03-28T08:43:58","date_gmt":"2021-03-28T12:43:58","guid":{"rendered":"https:\/\/swling.com\/blog\/?p=48268"},"modified":"2021-03-28T08:43:58","modified_gmt":"2021-03-28T12:43:58","slug":"jack-finds-that-chokes-have-a-huge-impact-on-switching-power-supply-noise","status":"publish","type":"post","link":"https:\/\/swling.com\/blog\/2021\/03\/jack-finds-that-chokes-have-a-huge-impact-on-switching-power-supply-noise\/","title":{"rendered":"Jack finds that chokes have a huge impact on switching power supply noise"},"content":{"rendered":"
\"\"<\/a>

These “Wall Wart” type adapters can create a lot of RFI<\/p><\/div>\n

Many thanks to SWLing Post<\/em> contributor, Jack Dully, who writes:<\/p>\n

I was putting some things in my radio junk parts box and came across some chokes. So I tried a test with my Tecsun PL-880 on battery and the Tecsun supplied switching AC adapter, with and without chokes on the adapter.<\/p>\n

WOW!<\/p>\n

I tuned to a vacant station on battery power with headphones on. Then on AC power, the hash and static were incredible. Putting one large choke on the adapter power cord, wrapped about four times and it decreased considerably. So I attached a second choke and once again the static & hash decreased even more, almost to the point of sounding like I was running just on battery power.<\/p>\n

Those chokes really do work well.<\/p><\/blockquote>\n

Thank you for sharing this, Jack. I almost never operate my portables while connected to a power supply, so I often forget about the importance of using a choke with inexpensive, lightweight radio power supplies. Thing is, so many things in our houses and shacks are powered by these QRM generators. In the shack, I’ve added chokes I’ve picked up at hamfests to a number of various power supplies. It does certainly help decrease the noise level. I’ve even used them on power cords for other appliances in the house that tend to spew RFI.<\/p>\n

If you ever find a deal on chokes at a hamfest or electronics store, grab some. They can be an affordable solution for those noisy power supplies we still rely on.<\/p>\n

Thank you for the reminder and\u00a0 tip, Jack!<\/p>\n","protected":false},"excerpt":{"rendered":"

Many thanks to SWLing Post contributor, Jack Dully, who writes: I was putting some things in my radio junk parts box and came across some chokes. So I tried a test with my Tecsun PL-880 on battery and the Tecsun supplied switching AC adapter, with and without chokes on the adapter. WOW! I tuned to […]<\/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":[545,3,196,43],"tags":[3324,8680,4089,2651,453],"class_list":["post-48268","post","type-post","status-publish","format-standard","hentry","category-ham-radio","category-news","category-qrm","category-shortwave-radio","tag-fighting-qrm","tag-jack-dully","tag-qrm","tag-radio-frequency-interference","tag-rfi"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_shortlink":"https:\/\/wp.me\/pn3uc-cyw","jetpack-related-posts":[{"id":45304,"url":"https:\/\/swling.com\/blog\/2020\/09\/qrm-busting-robs-practical-approach-to-tackling-unwanted-radio-noise\/","url_meta":{"origin":48268,"position":0},"title":"QRM-busting: Rob’s practical approach to tackling unwanted radio noise","author":"Thomas","date":"September 12, 2020","format":false,"excerpt":"Our good friend Rob Wagner (VK3BVW) over at the\u00a0 Mount Evelyn DX Report has posted an excellent article on how to deal with man-made radio interference (QRM\/RFI) in our homes and neighborhoods. This has been a frequent topic here on the SWLing Post (indeed, as recently as Thursday). I've copied\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\/2017\/07\/Kenwood-R-1000-Encoder-Dial-2.jpg?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2017\/07\/Kenwood-R-1000-Encoder-Dial-2.jpg?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2017\/07\/Kenwood-R-1000-Encoder-Dial-2.jpg?resize=525%2C300&ssl=1 1.5x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2017\/07\/Kenwood-R-1000-Encoder-Dial-2.jpg?resize=700%2C400&ssl=1 2x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2017\/07\/Kenwood-R-1000-Encoder-Dial-2.jpg?resize=1050%2C600&ssl=1 3x"},"classes":[]},{"id":13304,"url":"https:\/\/swling.com\/blog\/2015\/05\/sangean-blames-am-interference-on-power-supply-and-government-regulation\/","url_meta":{"origin":48268,"position":1},"title":"Sangean blames AM interference on power supply and government regulation","author":"Thomas","date":"May 20, 2015","format":false,"excerpt":"After the Sangean WR-15 received low marks for AM reception in an Amazon review, Bob of Sangean America\u00a0replied that\u00a0poor reception is due to the radio's switching power supply--a design that is federally mandated. Many thanks to Jeff over at the Herculodge for posting this (click here to read the full\u2026","rel":"","context":"In "AM"","block_context":{"text":"AM","link":"https:\/\/swling.com\/blog\/category\/am\/"},"img":{"alt_text":"Sangean-AMFM-Radio","src":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2015\/03\/Sangean-AMFM-Radio.jpg?resize=350%2C200","width":350,"height":200},"classes":[]},{"id":48313,"url":"https:\/\/swling.com\/blog\/2021\/03\/guest-post-indoor-noise-and-ferrites-part1\/","url_meta":{"origin":48268,"position":2},"title":"Guest Post: Indoor Noise and Ferrites, Part1","author":"Thomas","date":"March 30, 2021","format":false,"excerpt":"Many thanks to SWLing Post contributor, TomL, who shares the following guest post: Indoor Noise and Ferrites, Part 1 by TomL My magnet wire loop antenna on the porch reminded me to revisit aspects about my noisy Condo that I still needed to understand.\u00a0 Some RF noise I could control\u2026","rel":"","context":"In "Articles"","block_context":{"text":"Articles","link":"https:\/\/swling.com\/blog\/category\/articles\/"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2021\/03\/TVSignal.jpg?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2021\/03\/TVSignal.jpg?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2021\/03\/TVSignal.jpg?resize=525%2C300&ssl=1 1.5x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2021\/03\/TVSignal.jpg?resize=700%2C400&ssl=1 2x"},"classes":[]},{"id":11939,"url":"https:\/\/swling.com\/blog\/2015\/01\/charging-the-tecsun-pl-880-with-the-c-crane-witness-ac-adapter\/","url_meta":{"origin":48268,"position":3},"title":"Charging the Tecsun PL-880 with the C. Crane Witness AC Adapter","author":"Thomas","date":"January 9, 2015","format":false,"excerpt":"SWLing Post reader, John Case, comments: \"I bought a C. Crane Witness AC Adapter to try it out on the PL-880. It is rated at 900 mA, more than enough to handle the PL-880. I think it is more than reasonable at $14.95. I am happy to say that it\u2026","rel":"","context":"In "New Products"","block_context":{"text":"New Products","link":"https:\/\/swling.com\/blog\/category\/new-products\/"},"img":{"alt_text":"CCWitnessAdapter","src":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2015\/01\/CCWitnessAdapter.jpg?resize=350%2C200","width":350,"height":200},"classes":[]},{"id":22675,"url":"https:\/\/swling.com\/blog\/2016\/12\/chris-tracks-down-sources-of-radio-noise\/","url_meta":{"origin":48268,"position":4},"title":"Chris tracks down sources of radio noise","author":"Thomas","date":"December 6, 2016","format":false,"excerpt":"Many thanks to SWLing Post contributor, Chris Smolinski, who shares this guest post from his blog, RadioHobbyist.org: Yet Another !&*%$! Noise Source by Chris Smolinski The past few days, I have noticed higher than usual noise levels, generally on the lower frequencies, and particularly on the longwave band, including the\u2026","rel":"","context":"In "Ham Radio"","block_context":{"text":"Ham Radio","link":"https:\/\/swling.com\/blog\/category\/ham-radio\/"},"img":{"alt_text":"spectrum-waterfall-sdr","src":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2016\/12\/Spectrum-Waterfall-SDR.jpg?resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2016\/12\/Spectrum-Waterfall-SDR.jpg?resize=350%2C200 1x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2016\/12\/Spectrum-Waterfall-SDR.jpg?resize=525%2C300 1.5x"},"classes":[]},{"id":63912,"url":"https:\/\/swling.com\/blog\/2025\/09\/noise-reduction-ideas-via-hackaday-electronics-unmessed\/","url_meta":{"origin":48268,"position":5},"title":"Noise-Reduction Ideas via Hackaday & Electronics Unmessed","author":"Thomas","date":"September 9, 2025","format":false,"excerpt":"Many thanks to SWLing Post contributor Dennis Dura for sharing this excellent Hackaday feature: Quieting That Radio. If you\u2019ve ever struggled to hear weak signals through modern RFI, this piece, featuring content from Electronics Unmessed, is well worth checking out. It explores the hidden interference SDR setups often face and\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\/2016\/12\/Spectrum-Digital-Modes-e1482065447566.jpg?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2016\/12\/Spectrum-Digital-Modes-e1482065447566.jpg?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2016\/12\/Spectrum-Digital-Modes-e1482065447566.jpg?resize=525%2C300&ssl=1 1.5x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2016\/12\/Spectrum-Digital-Modes-e1482065447566.jpg?resize=700%2C400&ssl=1 2x"},"classes":[]}],"jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/swling.com\/blog\/wp-json\/wp\/v2\/posts\/48268","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=48268"}],"version-history":[{"count":0,"href":"https:\/\/swling.com\/blog\/wp-json\/wp\/v2\/posts\/48268\/revisions"}],"wp:attachment":[{"href":"https:\/\/swling.com\/blog\/wp-json\/wp\/v2\/media?parent=48268"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/swling.com\/blog\/wp-json\/wp\/v2\/categories?post=48268"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/swling.com\/blog\/wp-json\/wp\/v2\/tags?post=48268"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}