{"id":49992,"date":"2021-08-15T07:58:23","date_gmt":"2021-08-15T11:58:23","guid":{"rendered":"https:\/\/swling.com\/blog\/?p=49992"},"modified":"2021-08-15T08:02:20","modified_gmt":"2021-08-15T12:02:20","slug":"grayhats-ncpl-noise-cancelling-passive-loop-antenna-tweak","status":"publish","type":"post","link":"https:\/\/swling.com\/blog\/2021\/08\/grayhats-ncpl-noise-cancelling-passive-loop-antenna-tweak\/","title":{"rendered":"Grayhat’s NCPL (Noise-Cancelling Passive Loop) antenna “tweak”"},"content":{"rendered":"
\"\"<\/a>

My NCPL antenna<\/p><\/div>\n

Many thanks to SWLing Post<\/em> contributor, Grayhat, who shares the following modification he made to a Noise-Cancelling Passive Loop antenna<\/a> last year. He’s kindly allowed me to share his notes here, but apologized that at the time, he didn’t take photos of the project along the way and recycled many of the components into yet another antenna experiment. <\/strong><\/p>\n

Grayhat writes:<\/strong><\/p>\n

Here’s a simple tweak to the NCPL, made easy for anyone. Let’s start with the commercial NooElec 9:1 balun version 1 (not 2) … made in USA<\/a>.<\/p>\n

Look at the schematic of the balun:<\/p>\n

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

Cut the R1 (0 Ohm resistor – jumper) so that the center tap of the transformer won’t be connected to ground, then solder a short piece of wire to the tap.<\/p>\n

\"\"<\/a>

The first pic (top) shows the balun seen from top side, the arrow indicates the small hole going to the transformer tap.<\/p><\/div>\n

\"\"<\/a>

This pic shows the bottom of the board with the trace to cut and the spot for soldering the tap wire (needs cleaning with a bit of sandpaper to remove the cover paint). The solder is as easy as 1-2-3 once the trace is cut and the spot cleaned just insert a wire from the top of the board and solder it to the bottom and there you go!<\/p><\/div>\n

Build the NCPL using “fat” coax (RG8 will do) with the top cross connection.<\/p>\n

\"\"<\/a>

NCPL modification schematic<\/p><\/div>\n

Side note: the top “cross connection” is the weak point, so it would be a good idea putting a short piece of (say) PVC pipe over that point, the piece will also help suspending the loop or sticking its top to the support pole, as for the feedpoint, a small electrical junction box will fit and protect the tiny balun from bad weather<\/p>\n

Now the difference: connect the two center conductors of the NCPL to the balun input and the braid to the wire going to the center tap (as above).<\/p>\n

Such a configuration will give some advantages over the “standard” NCPL one. The loop will now be galvanically isolated from the feedline\/receiver so it will have much less “static noise.” Due to the tap, the typical 8 pattern of the loop will be preserved, this means that the loop will now have much deeper nulls.<\/p>\n

By the way, the balun could just be wound w\/o buying it. I suggested the nooelec since that way anyone with little soldering ability will be able to put it together. Oh and by the way it’s then possible adding a small preamp at the balun output if one really wants, any preamp accepting a coax input will work. \ud83d\ude42<\/p>\n

Again, if you can\/want, give it a try !<\/p>\n

Many thanks for sharing this, Grayhat! We always welcome your inexpensive, innovative urban antenna projects<\/a>!<\/strong><\/p>\n

Post readers<\/em>: If you have question, feel free to comment and I’m sure Grayhat can help.\u00a0<\/strong><\/p>\n","protected":false},"excerpt":{"rendered":"

Many thanks to SWLing Post contributor, Grayhat, who shares the following modification he made to a Noise-Cancelling Passive Loop antenna last year. He’s kindly allowed me to share his notes here, but apologized that at the time, he didn’t take photos of the project along the way and recycled many of the components into yet […]<\/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":[3607,3194,627,3,43],"tags":[1643,7880,4359,4667,8413,8412,8075],"class_list":["post-49992","post","type-post","status-publish","format-standard","hentry","category-antennas","category-guest-posts","category-how-to","category-news","category-shortwave-radio","tag-antennas","tag-grayhat","tag-homebrew-mag-loop-antenna","tag-loop-antennas","tag-ncpl-antenna","tag-noise-cancelling-passive-loop-antenna","tag-nooelec-balun-19-v2"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_shortlink":"https:\/\/wp.me\/pn3uc-d0k","jetpack-related-posts":[{"id":43017,"url":"https:\/\/swling.com\/blog\/2020\/04\/john-adds-a-pre-amp-and-rotatable-stand-to-his-homebrew-ncpl-antenna\/","url_meta":{"origin":49992,"position":0},"title":"John adds a pre-amp and rotatable stand to his homebrew NCPL antenna","author":"Thomas","date":"April 26, 2020","format":false,"excerpt":"A couple weeks ago, we featured John Mills' homebrew Noise-Cancelling Passive Loop (NCPL) antenna (see photo above) in a post with two other Post community designs. John recently shared an update to his project: As promised, some more pictures of my antenna mounted on a rotatable stand. I have used\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\/04\/John-Mills-NCPL-Antenna-Close-up.jpeg?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2020\/04\/John-Mills-NCPL-Antenna-Close-up.jpeg?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2020\/04\/John-Mills-NCPL-Antenna-Close-up.jpeg?resize=525%2C300&ssl=1 1.5x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2020\/04\/John-Mills-NCPL-Antenna-Close-up.jpeg?resize=700%2C400&ssl=1 2x"},"classes":[]},{"id":44834,"url":"https:\/\/swling.com\/blog\/2020\/08\/bruce-compares-two-homebrew-ncpl-antennas-to-the-airspy-youloop\/","url_meta":{"origin":49992,"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":42856,"url":"https:\/\/swling.com\/blog\/2020\/04\/hack-a-broken-vga-cable-to-make-a-binocular-ferrite-cores-for-your-ncpl-antenna\/","url_meta":{"origin":49992,"position":2},"title":"Hack a broken VGA cable to make a binocular ferrite cores for your NCPL antenna","author":"Thomas","date":"April 15, 2020","format":false,"excerpt":"Many thanks to Oscar (EA3IBC) who shares this simple hack. I've gotten quite a few emails from Post readers telling me that the only thing holding them back from building a NCPL antenna is the BN-73-302 binocular ferrite core needed for the 1:1 Balun. While so much of the world\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\/04\/NCPL-Noise-Cancelling-Passive-Loop-Antenna-970x1024.jpg?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2020\/04\/NCPL-Noise-Cancelling-Passive-Loop-Antenna-970x1024.jpg?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2020\/04\/NCPL-Noise-Cancelling-Passive-Loop-Antenna-970x1024.jpg?resize=525%2C300&ssl=1 1.5x"},"classes":[]},{"id":42815,"url":"https:\/\/swling.com\/blog\/2020\/04\/beating-the-quarantine-blues-readers-build-homebrew-ncpl-antennas\/","url_meta":{"origin":49992,"position":3},"title":"Beating the Quarantine Blues: Readers build homebrew NCPL antennas","author":"Thomas","date":"April 13, 2020","format":false,"excerpt":"Recently, I published a step-by-step guide on building a Noise-Cancelling Passive Loop (NCPL) antenna. 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If so, my apologies!] I think this passive loop antenna project has been so appealing because (1.) most of us around the world\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\/04\/IMG20200408142726-197x300.jpeg?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2020\/04\/IMG20200408142726-197x300.jpeg?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2020\/04\/IMG20200408142726-197x300.jpeg?resize=525%2C300&ssl=1 1.5x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2020\/04\/IMG20200408142726-197x300.jpeg?resize=700%2C400&ssl=1 2x"},"classes":[]},{"id":48622,"url":"https:\/\/swling.com\/blog\/2021\/04\/giuseppe-is-impressed-with-the-performance-of-his-homebrew-passive-loop-antenna\/","url_meta":{"origin":49992,"position":4},"title":"Giuseppe is impressed with the performance of his homebrew passive loop antenna","author":"Thomas","date":"April 22, 2021","format":false,"excerpt":"Many thanks to\u00a0SWLing Post\u00a0contributor, Giuseppe Morl\u00e8 (IZ0GZW), who shares the following: Dear Thomas, I'm Giuseppe Morl\u00e8 from central Italy, the Tyrrhenian Sea, Formia. Today I tested my noise canceling loop inside the radio station by comparing it to the crossed loops. Again, like my medium wave T Ferrite, this loop\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\/2021\/04\/Giuseppe.jpg?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2021\/04\/Giuseppe.jpg?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2021\/04\/Giuseppe.jpg?resize=525%2C300&ssl=1 1.5x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2021\/04\/Giuseppe.jpg?resize=700%2C400&ssl=1 2x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2021\/04\/Giuseppe.jpg?resize=1050%2C600&ssl=1 3x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2021\/04\/Giuseppe.jpg?resize=1400%2C800&ssl=1 4x"},"classes":[]},{"id":43158,"url":"https:\/\/swling.com\/blog\/2020\/05\/patrizios-simple-homebrew-ncpl-antenna\/","url_meta":{"origin":49992,"position":5},"title":"Patrizio’s simple homebrew NCPL antenna","author":"Thomas","date":"May 7, 2020","format":false,"excerpt":"Many thanks to SWLing Post contributor, Patrizio Cardelli, who writes: I'm Patrizio (SWL I - 5184 \/AN) from Riva del Garda, Italy. A few days ago, I built a Noise-Cancelling Passive Loop (NCPL) antenna. I built the 1:1 balun with a couple of ferrite 175 - 285. 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