{"id":45481,"date":"2020-09-20T10:34:22","date_gmt":"2020-09-20T14:34:22","guid":{"rendered":"https:\/\/swling.com\/blog\/?p=45481"},"modified":"2020-09-20T10:34:22","modified_gmt":"2020-09-20T14:34:22","slug":"post-storm-power-outage-leads-emilio-to-find-the-rfi-spewing-source-of-his-problems","status":"publish","type":"post","link":"https:\/\/swling.com\/blog\/2020\/09\/post-storm-power-outage-leads-emilio-to-find-the-rfi-spewing-source-of-his-problems\/","title":{"rendered":"Post-storm power outage leads Emilio to find the RFI-spewing source of his problems"},"content":{"rendered":"

\"Storm<\/a>Many thanks to SWling Post<\/em> contributor, Emilio Ruiz<\/a>, who shares the following guest post:<\/strong><\/p>\n

\n

Apprehending an RFI-generating monster!<\/h1>\n

At the beginning of the year, I was sad because, at home, an awful<\/em> RFI noise appeared. The next few months the noise increase until S9!!. Day and night my receivers and my feelings were so dampened with this terrific RFI–only the lower Broadcast Band (900 to 540 Khz) was relatively immune to it.<\/p>\n

Yesterday, we had a storm and the mains electricity service went off, so I connect a 12 volt battery to my RT-749b<\/strong> military surplus transceiver and the received signals were very clean like the “good old days”.<\/p>\n

https:\/\/www.emilio.com.mx\/swling\/rfi-rt-749b-1-small.mp4<\/a><\/video><\/div>\n

(Above: Listen W1AW loong distant from my QTH in Chiapas Mexico).<\/p>\n

When the power electricity come back on, so did the RFI too!!<\/p>\n

https:\/\/www.emilio.com.mx\/swling\/rfi-rt-749b-2-small.mp4<\/a><\/video><\/div>\n

(Above: W1AW gone)<\/p>\n

Remembering the recently publish post in SWLing Post about RFI<\/a>, I did some testing by
\ncutting the electricity to my home (the main switch) and the RFI was gone!! So I discovered the RFI lives in my house–not in the outside wires!!<\/p>\n

I put batteries in my old shortwave portable radio and searched (like Ghostbusters) all outlets contacts, one by one, connect and disconnected each device.<\/p>\n

And I found the guilty party!<\/h2>\n
\"\"<\/a>

Exhibit A: The Mitzu laptop power supply<\/p><\/div>\n

On December 2019, the power supply of my son’s laptop broke, so I bought a cheap substitute.<\/p>\n

The RFI produced by this little monster could be heard at a distance of about 200 meters<\/strong> from my QTH!!! (Much like an old transmitter spark gap–!)<\/p>\n

Even this cheap power supply apparently featured ferrite toroids on the wire but turns out it is fake!! It was only a plastic ball!<\/p>\n

\"\"<\/a>

Exhibit B: Fake toroids!<\/p><\/div>\n

The wires were also not shielded. No doubt one of the worst switched-mode power supplies I could have purchased.<\/p>\n

\"\"<\/a>

Exhibit C: The Mitzu RFI generator wire without shield, only pair wires!<\/p><\/div>\n

I found a old Acer power supply with same specs and I replaced out the RFI monster one.<\/p>\n

And now? The shortwave bands are clean again.<\/p>\n

https:\/\/www.emilio.com.mx\/swling\/rfi-kenwood-r-600-small.mp4<\/a><\/video><\/div>\n

(Video: Testing my Kenwood R-600 rx with Radio Exterior de Espa\u00f1a… plugging and unplug the Mitzu monster RFI generator).<\/p>\n

So I wanted to share what happened to me, so perhaps it can be useful for other SWLing Post blog friends.<\/p>\n

Watch these little switched mode power supplies from all devices in your home. Replace them if you detect RFI levels that harms SWLing. Consider disconnect all devices (vampire consumption–or phantom loads) if not in use; the radio waves and electric bill will be grateful to you!<\/p>\n

\n

WOW! What a difference! Emilio, that was great investigative work on your part. It’s as if that switching power supply was specifically designed to create RFI! No shield and fake toroids? That’s just criminal in my world!\u00a0<\/strong><\/em><\/p>\n

Thank you so much for sharing your story. Hopefully, this might encourage others to investigate and apprehend their own local RFI monsters!<\/strong><\/em><\/p>\n

(And by the way, Emilio, I love that RT-749b military transceiver!)<\/strong><\/em><\/p>\n","protected":false},"excerpt":{"rendered":"

Many thanks to SWling Post contributor, Emilio Ruiz, who shares the following guest post: Apprehending an RFI-generating monster! At the beginning of the year, I was sad because, at home, an awful RFI noise appeared. The next few months the noise increase until S9!!. Day and night my receivers and my feelings were so dampened […]<\/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":[3194,545,627,3,196,43],"tags":[3842,7522,2505,3898,2650,4089,2651,1296,453,8831,2214],"class_list":["post-45481","post","type-post","status-publish","format-standard","hentry","category-guest-posts","category-ham-radio","category-how-to","category-news","category-qrm","category-shortwave-radio","tag-am-noise","tag-emilio-ruiz","tag-how-to-filter-noise-from-shortwave","tag-mitigating-radio-noise","tag-noise","tag-qrm","tag-radio-frequency-interference","tag-rf-noise","tag-rfi","tag-rt-749b-military-transceiver","tag-shortwave-noise"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_shortlink":"https:\/\/wp.me\/pn3uc-bPz","jetpack-related-posts":[{"id":45271,"url":"https:\/\/swling.com\/blog\/2020\/09\/cant-receive-anything-on-your-new-shortwave-radio-read-this\/","url_meta":{"origin":45481,"position":0},"title":"Can’t receive anything on your new shortwave radio–? Read this.","author":"Thomas","date":"September 10, 2020","format":false,"excerpt":"This morning, I received a question from Andrew, an SWLing Post reader in the UK.\u00a0 Andrew writes: May I ask a question please? I am very much a newbie to this. I am not really interested in FM, but I would like to listen to international stations on SW, utilities\u2026","rel":"","context":"In "AM"","block_context":{"text":"AM","link":"https:\/\/swling.com\/blog\/category\/am\/"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2015\/05\/PL-680-BBC-Click-Frequency.jpg?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2015\/05\/PL-680-BBC-Click-Frequency.jpg?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2015\/05\/PL-680-BBC-Click-Frequency.jpg?resize=525%2C300&ssl=1 1.5x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2015\/05\/PL-680-BBC-Click-Frequency.jpg?resize=700%2C400&ssl=1 2x"},"classes":[]},{"id":25040,"url":"https:\/\/swling.com\/blog\/2017\/04\/advice-on-cancelling-locally-generated-noise\/","url_meta":{"origin":45481,"position":1},"title":"Advice on cancelling locally generated noise","author":"Thomas","date":"April 5, 2017","format":false,"excerpt":"An SWLing Post reader recently contacted me with the following question: \"What devices work well to cancel out local RFI? I've been told that both the Timewave ANC-4 and a number of BHI products are all worth considering.\" Unfortunately (or fortunately, for me) I've no experience with outboard DSP or\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\/04\/Timewave-ANC-4.jpg?resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2017\/04\/Timewave-ANC-4.jpg?resize=350%2C200 1x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2017\/04\/Timewave-ANC-4.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":45481,"position":2},"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":[]},{"id":45304,"url":"https:\/\/swling.com\/blog\/2020\/09\/qrm-busting-robs-practical-approach-to-tackling-unwanted-radio-noise\/","url_meta":{"origin":45481,"position":3},"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":34180,"url":"https:\/\/swling.com\/blog\/2018\/09\/arcing-can-produce-nasty-broadband-radio-interference\/","url_meta":{"origin":45481,"position":4},"title":"Arcing can produce nasty broadband radio interference","author":"Thomas","date":"September 21, 2018","format":false,"excerpt":"I mentioned in a previous post that, this year, QRM levels here at the condo in Qu\u00e9bec are higher on our balcony than they are inside the building. I think I found the source. A couple weeks ago, on my morning walk, I passed underneath some high voltage power lines\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\/2018\/01\/Elecraft-KX2-PK-Loop-Condo.jpg?resize=350%2C200&ssl=1","width":350,"height":200},"classes":[]},{"id":47855,"url":"https:\/\/swling.com\/blog\/2021\/02\/lemons-into-lemonade-nick-is-taking-advantage-of-texas-power-outage-to-play-radio\/","url_meta":{"origin":45481,"position":5},"title":"Lemons into Lemonade: Nick is taking advantage of Texas power outage to play radio","author":"Thomas","date":"February 19, 2021","format":false,"excerpt":"Many thanks to SWLing Post contributor, Nick Booras, who writes: I am stuck in the house in Texas, bored and with no power. So I decided to make a couple videos with my phone. One nice thing about a power outage... no RFI [Radio Frequency Interference]. This Icom 705 is\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\/2020\/10\/Radio-Exterior-IC-705-Waterfall-Display.jpg?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2020\/10\/Radio-Exterior-IC-705-Waterfall-Display.jpg?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2020\/10\/Radio-Exterior-IC-705-Waterfall-Display.jpg?resize=525%2C300&ssl=1 1.5x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2020\/10\/Radio-Exterior-IC-705-Waterfall-Display.jpg?resize=700%2C400&ssl=1 2x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2020\/10\/Radio-Exterior-IC-705-Waterfall-Display.jpg?resize=1050%2C600&ssl=1 3x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2020\/10\/Radio-Exterior-IC-705-Waterfall-Display.jpg?resize=1400%2C800&ssl=1 4x"},"classes":[]}],"jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/swling.com\/blog\/wp-json\/wp\/v2\/posts\/45481","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=45481"}],"version-history":[{"count":0,"href":"https:\/\/swling.com\/blog\/wp-json\/wp\/v2\/posts\/45481\/revisions"}],"wp:attachment":[{"href":"https:\/\/swling.com\/blog\/wp-json\/wp\/v2\/media?parent=45481"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/swling.com\/blog\/wp-json\/wp\/v2\/categories?post=45481"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/swling.com\/blog\/wp-json\/wp\/v2\/tags?post=45481"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}