{"id":47496,"date":"2021-01-28T10:10:25","date_gmt":"2021-01-28T14:10:25","guid":{"rendered":"https:\/\/swling.com\/blog\/?p=47496"},"modified":"2021-01-28T10:10:25","modified_gmt":"2021-01-28T14:10:25","slug":"build-an-affordable-but-stealthy-magnet-wire-vertical-loop-antenna-to-mitigate-condo-qrm","status":"publish","type":"post","link":"https:\/\/swling.com\/blog\/2021\/01\/build-an-affordable-but-stealthy-magnet-wire-vertical-loop-antenna-to-mitigate-condo-qrm\/","title":{"rendered":"Build an affordable (but stealthy) Magnet Wire Vertical Loop antenna to mitigate condo QRM"},"content":{"rendered":"

Many thanks to SWLing Post contributor,\u00a0TomL<\/a>, who shares the following guest post:<\/strong><\/em><\/p>\n

\n

Magnet Wire Vertical Loop Antenna<\/h1>\n

by TomL<\/strong><\/p>\n

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

For those of you in a noisy condo like me, the environment does not give me many options.\u00a0 I was experimenting with a YouLoop on the wooden porch with somewhat acceptable results.\u00a0 For its size, it is an excellent performer, especially on the lower bands.\u00a0 Here is a very interesting review of the YouLoop<\/a>, including close-up pictures of the innards of the phase inverter and 1:1 balun, by John S. Huggins.\u00a0 However, it is not waterproof and I was concerned about the ice and snow ruining it.\u00a0 I could tape up the connectors with waterproof tape but I also wanted\u00a0 something with a bigger capture area.\u00a0 A magnet wire stealth antenna might be just the thing!<\/p>\n

I just happened to have a waterproof 1:1 ATU balun from Balun Designs<\/a> that I was going to use for future Amateur Radio use whenever I get around to passing the next level test; it is total overkill for what I intended to use it for.\u00a0 It would make a good connection point and (this one) also acts as an RF choke as well.\u00a0 One can make a 1:1 balun by buying the right Type of ferrite core and winding it yourself.\u00a0 Here is just one idea from Palomar Engineers<\/a>.<\/p>\n

So I dusted it off, went to a local store to get a 100 foot spool of 26 gauge magnet wire and tested it strung up around my living room. It came out to be a rectangle about 42 feet in circumference.\u00a0 Results were usable. I expected lots of noise and there is a great deal across the bands, so only the strongest shortwave stations were received. However, I was surprised by how strong the mediumwave band was and good to listen to without an amplifier.<\/p>\n

I am ambivalent towards trying to perfectly match the impedance since this is a broadband receive-only antenna and the impedance will vary greatly over MW and SW bands.\u00a0 And I don’t want to mess with a remotely controlled tuned loop since this antenna was destined for the outdoor porch.\u00a0 I tried a Cross Country Wireless preselector<\/a> at my desk but had some mixed results.\u00a0 I later found out, by disconnecting things in series, that the preselector inline raised the noise level about 5 dBm, so I took it out for now. Perhaps it needs more internal shielding or the connecting cable is bad.<\/p>\n

Polarization is an issue, too.\u00a0 I have read that most man-made noise (QRM) is vertically polarized, so why would I use a vertically oriented loop?\u00a0 Then I saw David Casler’s video on loop antennas <\/a>where he explains that connecting a vertical loop antenna at the bottom or the top makes it horizontally polarized (connecting the coax on the side makes it vertically polarized).\u00a0 I never knew that!\u00a0 Horizontal polarization will mitigate some of the offending QRM as well as match the polarization of mediumwave band transmitters.\u00a0 Furthermore, I read that a horizontal loop will have poor signal pickup at low frequencies because it is not high enough off the ground, similar to a horizontal dipole<\/a>. For now, a vertical loop connected to facilitate horizontal polarization is what I want.<\/p>\n

A note about wire size. People make a big deal about it but those are mostly amateur radio people.\u00a0 Transmission depends on efficiency so things like wire size, skin effect, standing waves, and other things matter (see here, for example<\/a>).\u00a0 With a receive-only antenna it is OK to use very thin wire.\u00a0 Resonance can matter if you want the last ounce of signal strength with an antenna tuner, like in high-Q type loops where the bandwidth is very narrow and you are using a multi-turn loop with variable capacitor and a pick-up coil of wire to the receiver.\u00a0 Comparatively, my simple loop is depending more on a single turn of wire, the aperture size, length of wire for its performance, and carefully isolating the feedline coax using RF chokes at both ends.<\/p>\n

Here is one example of a strong station from Cuba I was able to record because WLW was off the air for some unexpected reason.<\/p>\n

Radio Reloj, Cuba 870 kHz (At the end, you can hear WLW come back online with CBS news):<\/p>\nhttps:\/\/swling.com\/blog\/wp-content\/uploads\/2021\/01\/08-Jan-2021-04h57m55sZ-870-kHz-ECSS-L-RReloj.mp3<\/a><\/audio>\n

Side note about Radio Reloj on Wikipedia<\/a>, the strange format seems to fit well with a totalitarian regime, including a \u201ccorrector\u201d who \u201ccorrects the content\/writing errors to meet the requirements\u201d.\u00a0 Read the wiki link for yourself.\u00a0 Not a society I want to live in, thank you very much!<\/p>\n

Example of 80 meter band performance – Greetings to a new person from members of the \u201cAwful, Awful, Ugly Net\u201d, 3855 kHz:<\/p>\nhttps:\/\/swling.com\/blog\/wp-content\/uploads\/2021\/01\/07-Jan-2021-03h35m41sZ-3.855-MHz-LSB-Awful-Awful-Ugly-Net.mp3<\/a><\/audio>\n

Encouraged by the results, I \u201cinstalled\u201d the magnet wire around the support beams of the wooden porch, wrapping it carefully to create a square loop. Holding it in place is a brick at each bottom corner since I am not allowed to nail anything into the Association-owned porch.\u00a0 The length came out to about 32 feet (8 feet per side), so I trimmed it and connected to the balun.\u00a0 I also added an RF choke at the Airspy HF+ input from Palomar Engineers<\/a> which helped bring noise down a couple of S-units. \u00a0 That might not sound like a lot but by also shutting off the living room air filter and an AC switch with \u201cwall-wart\u201d AC power adapters on it, I was able to reduce the noise a little bit more.\u00a0 There is still a lot of noise from the neighbors, so it is not a perfect situation.<\/p>\n

Here are two examples of reception with the outside installation.<\/p>\n

Gateway 160 Meter Radio Newsletter<\/a>, broadcast (in AM) by WA0RCR every Saturday on 1860 kHz:<\/p>\nhttps:\/\/swling.com\/blog\/wp-content\/uploads\/2021\/01\/10-Jan-2021-04h52m18sZ-1.86-MHz-SAM-WA0RCR.mp3<\/a><\/audio>\n

Side note about the Radio Newsletter.\u00a0 I stumbled on it when using the YouLoop and found that some of the content is very interesting and informative.\u00a0 Of course it is geared mostly towards amateur radio but some of the news items are of general radio interest as well. It airs 1pm Saturday through 2am Sunday, USA Central Time.\u00a0 Obviously, many segments repeat during that lengthy timeframe and reception depends on propagation from Missouri.<\/p>\n

KDDR 1220 kHz, West Fargo, ND station ID (presumably \u201cnighttime\u201d power of 327 watts):<\/p>\nhttps:\/\/swling.com\/blog\/wp-content\/uploads\/2021\/01\/10-Jan-2021-00h01m59sZ-1.22-MHz-SAM-KDDR-The-Tornado.mp3<\/a><\/audio>\n

The shortwave bands are still a noisy disaster but signal levels are higher compared to the YouLoop.\u00a0 Only the strongest stations come in like WRMI, WHRI, Radio Espana, Radio Habana, and CRI. And I can hear the loudest amateur radio operators.<\/p>\n

Just for grins, here is Radio Rebelde on 5025 kHz when band conditions were above average:<\/p>\nhttps:\/\/swling.com\/blog\/wp-content\/uploads\/2021\/01\/13-Jan-2021-06h49m04sZ-5.025-MHz-SAM-RREBELDE.mp3<\/a><\/audio>\n

Another phenomenon I am looking into is the reception pattern of a vertical loop.\u00a0 Less than 1\/10th wavelength, the null is through the center of the loop.\u00a0 At one wavelength, the null manifests in the plane of the wire loop<\/a>.\u00a0 They are too close to phase them but switching between two directional loop antennas might improve reception depending on frequency.\u00a0 We shall see in the future.<\/p>\n

At least for now, I have a decent mediumwave band which performs better than the useful CCrane Twin-Ferrite<\/a> amplified loop antenna that was used in the (noisy) indoors, I can hear the 160 & 80 meter amateur bands better, and the reception of the strongest shortwave broadcasters are more predictable.\u00a0 Not bad for four dollars of wire!<\/p>\n

\n

Brilliant, Tom! Again, I love how you’ve not only made an inexpensive antenna, but you’ve even done it within your HOA regulations. You’re right, too: if you’re not transmitting into an antenna, it blows the experimentation door wide open! Thank you once again for sharing your project with us.<\/strong><\/em><\/p>\n

Click here to check out all of Tom\u2019s guest posts and portable adventures!<\/a><\/strong><\/p>\n","protected":false},"excerpt":{"rendered":"

Many thanks to SWLing Post contributor,\u00a0TomL, who shares the following guest post: Magnet Wire Vertical Loop Antenna by TomL For those of you in a noisy condo like me, the environment does not give me many options.\u00a0 I was experimenting with a YouLoop on the wooden porch with somewhat acceptable results.\u00a0 For its size, it […]<\/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":[3607,8,3194,3,196,746,43,158],"tags":[9106,9105,8498,4359,3325,9104,4089,7281,8536,5119],"class_list":["post-47496","post","type-post","status-publish","format-standard","hentry","category-antennas","category-articles","category-guest-posts","category-news","category-qrm","category-recordings","category-shortwave-radio","category-software-defined-radio","tag-antennas-for-condo","tag-hoa","tag-homebrew-antennas","tag-homebrew-mag-loop-antenna","tag-how-to-fight-qrm","tag-magnet-wire-antenna","tag-qrm","tag-shortwave-antennas-apartments","tag-stealth-antennas","tag-toml"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_shortlink":"https:\/\/wp.me\/pn3uc-cm4","jetpack-related-posts":[{"id":50098,"url":"https:\/\/swling.com\/blog\/2021\/08\/wire-antennas-vs-mag-loop-antennas\/","url_meta":{"origin":47496,"position":0},"title":"Wire antennas vs. mag loop antennas","author":"Thomas","date":"August 29, 2021","format":false,"excerpt":"In the past few weeks, I've gotten a lot of questions from readers who are trying to decide if they should install a magnetic loop antenna or a simple wire antenna at their home. Obviously, most of the questions come from shortwave radio listeners, but some have come from ham\u2026","rel":"","context":"In "Antennas"","block_context":{"text":"Antennas","link":"https:\/\/swling.com\/blog\/category\/antennas\/"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2014\/06\/Elecraft-KX3.jpg?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2014\/06\/Elecraft-KX3.jpg?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2014\/06\/Elecraft-KX3.jpg?resize=525%2C300&ssl=1 1.5x"},"classes":[]},{"id":44834,"url":"https:\/\/swling.com\/blog\/2020\/08\/bruce-compares-two-homebrew-ncpl-antennas-to-the-airspy-youloop\/","url_meta":{"origin":47496,"position":1},"title":"Bruce compares two homebrew NCPL antennas to the Airspy Youloop","author":"Thomas","date":"August 16, 2020","format":false,"excerpt":"Many thanks to SWLing Post contributor, Bruce (VE3EAR), who writes: I decided that more testing of the Noise-Cancelling Passive Loop (YouLoop) antenna was needed, but I wanted to start with a clean page. I built two identical loops using some 3\/8 inch heliax scraps I had on hand. Both are\u2026","rel":"","context":"In "Antennas"","block_context":{"text":"Antennas","link":"https:\/\/swling.com\/blog\/category\/antennas\/"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2020\/08\/YouLoop2.jpeg?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2020\/08\/YouLoop2.jpeg?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2020\/08\/YouLoop2.jpeg?resize=525%2C300&ssl=1 1.5x"},"classes":[]},{"id":48313,"url":"https:\/\/swling.com\/blog\/2021\/03\/guest-post-indoor-noise-and-ferrites-part1\/","url_meta":{"origin":47496,"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":53845,"url":"https:\/\/swling.com\/blog\/2022\/08\/small-unidirectional-loop-antenna-sula-part-3-questions-answers\/","url_meta":{"origin":47496,"position":3},"title":"Small Unidirectional Loop Antenna (SULA) Part 3: Questions & Answers","author":"13dka","date":"August 31, 2022","format":false,"excerpt":"Many thanks to\u00a0SWLing Post\u00a0contributor extraordinaire,\u00a013dka, who brings us Part Two of a three part series about the new SULA homebrew antenna project.\u00a0This first article describes this affordable antenna and demonstrates its unique reception properties. The second article focuses on construction notes. This third and final article will essentially be a\u2026","rel":"","context":"In "Antennas"","block_context":{"text":"Antennas","link":"https:\/\/swling.com\/blog\/category\/antennas\/"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2022\/08\/SULA_alt_LNA_pos-scaled.jpg?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2022\/08\/SULA_alt_LNA_pos-scaled.jpg?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2022\/08\/SULA_alt_LNA_pos-scaled.jpg?resize=525%2C300&ssl=1 1.5x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2022\/08\/SULA_alt_LNA_pos-scaled.jpg?resize=700%2C400&ssl=1 2x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2022\/08\/SULA_alt_LNA_pos-scaled.jpg?resize=1050%2C600&ssl=1 3x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2022\/08\/SULA_alt_LNA_pos-scaled.jpg?resize=1400%2C800&ssl=1 4x"},"classes":[]},{"id":31336,"url":"https:\/\/swling.com\/blog\/2018\/03\/backpack-shack-2-0-an-update-from-the-field\/","url_meta":{"origin":47496,"position":4},"title":"Backpack Shack 2.0: an update from the field","author":"Thomas","date":"March 25, 2018","format":false,"excerpt":"Many thanks to\u00a0SWLing Post contributor,\u00a0TomL, who shares the following update about his homebrew Backpack Shack 2.0 portable loop antenna: Quick Field update by TomL This is just a quick Field Update for my Backpack Shack 2.0 antenna. It is not the most powerful antenna but in the right location it\u2026","rel":"","context":"In "Antennas"","block_context":{"text":"Antennas","link":"https:\/\/swling.com\/blog\/category\/antennas\/"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2018\/01\/8finalsetup-603x1024.jpg?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2018\/01\/8finalsetup-603x1024.jpg?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2018\/01\/8finalsetup-603x1024.jpg?resize=525%2C300&ssl=1 1.5x"},"classes":[]},{"id":19251,"url":"https:\/\/swling.com\/blog\/2016\/06\/guest-post-my-evolving-morphing-sw-listening-station\/","url_meta":{"origin":47496,"position":5},"title":"Guest Post: My Evolving, Morphing, SW Listening Station","author":"Thomas","date":"June 5, 2016","format":false,"excerpt":"Many thanks to SWLing Post contributor, TomL, for the following guest post: My Evolving, Morphing, SW Listening Station by\u00a0TomL, May 26, 2016 My interest in radio listening has been rekindled after a long hiatus in parallel to my dwindling interest in Mainstream Media.\u00a0 It is now about 8 years without\u2026","rel":"","context":"In "AM"","block_context":{"text":"AM","link":"https:\/\/swling.com\/blog\/category\/am\/"},"img":{"alt_text":"Sony-2010","src":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2016\/05\/Sony-2010-1024x632.jpg?resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2016\/05\/Sony-2010-1024x632.jpg?resize=350%2C200 1x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2016\/05\/Sony-2010-1024x632.jpg?resize=525%2C300 1.5x"},"classes":[]}],"jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/swling.com\/blog\/wp-json\/wp\/v2\/posts\/47496","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=47496"}],"version-history":[{"count":0,"href":"https:\/\/swling.com\/blog\/wp-json\/wp\/v2\/posts\/47496\/revisions"}],"wp:attachment":[{"href":"https:\/\/swling.com\/blog\/wp-json\/wp\/v2\/media?parent=47496"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/swling.com\/blog\/wp-json\/wp\/v2\/categories?post=47496"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/swling.com\/blog\/wp-json\/wp\/v2\/tags?post=47496"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}