{"id":47249,"date":"2021-01-12T09:16:02","date_gmt":"2021-01-12T13:16:02","guid":{"rendered":"https:\/\/swling.com\/blog\/?p=47249"},"modified":"2021-01-12T09:16:02","modified_gmt":"2021-01-12T13:16:02","slug":"loop-on-ground-antenna-part-2-tom-upgrades-his-low-profile-low-noise-portable-dxing-antenna","status":"publish","type":"post","link":"https:\/\/swling.com\/blog\/2021\/01\/loop-on-ground-antenna-part-2-tom-upgrades-his-low-profile-low-noise-portable-dxing-antenna\/","title":{"rendered":"Loop-On-Ground Antenna Part 2: Tom upgrades his low profile, low noise, portable DXing antenna"},"content":{"rendered":"

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

\n

Loop on Ground Part 2<\/b><\/h1>\n

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

My previous Loop on Ground (LoG) experiment<\/a> was useful which entailed connecting my Wellbrook loop amplifier to a 100 foot loop of speaker wire in the field at my favorite local Forest Preserve. It really brought in stations I had never heard before or strong stations in a more powerful way that made the audio really pleasant to listen to.\u00a0 This report will describe more experiments with smaller wire loops to see what the limitations are.\u00a0 100 feet of wire is quite a lot of wire to mess around with especially in the cold weather or public places that do not have as much private space.<\/p>\n

I don’t understand all the electrical interrelationships but a long posting at RadioReference.com had\u00a0 a great discussion about creating a 160-20 meters LoG receive-only antenna. It is 11 pages long but is worth reading how \u201cnanZor\u201d experimented with various parameters for general use. Kudos to him for documenting the findings as the design changed over time. You can find it here:<\/p>\n

https:\/\/forums.radioreference.com\/threads\/160-20m-log-loop-on-ground.370110\/<\/a><\/p>\n

nanZor basically boils it down to a few guidelines.<\/p>\n

    \n
  1. Keep it on the ground. Lifting the wire more than an inch or two decreased the lower angle signal reception greatly.<\/li>\n
  2. Calculate the optimal length for one full wavelength of wire at the highest target frequency, say for example, the top of the 20 meter band (14350 kHz). 936\/14.350 MHz * 0.9 velocity factor of simple insulated wire = 58.7 feet.\u00a0 You can round up to 60 feet, no big deal since this is broadband.\u00a0 The antenna should have a predictable reception pattern from 1\/10th wavelength up to 1 full wavelength. Outside that range, the pattern gets \u201csquirrely\u201d.<\/li>\n
  3. Using a 9:1 balun seemed to be a little better than a 4:1 balun at the antenna feedpoint. This gets into things I cannot measure and has to do with rising impedance as a loop gets closer to ground level. I am not sure but I think my Wellbrook amp has a built in 4:1 balun and it seems to work just fine.<\/li>\n
  4. Make sure to use an RF Choke at BOTH sides of the feedline coax cable. He was adamant that the loop can get easily unbalanced and allow noise into the antenna and\/or feedline and so it must be isolated and the ground allowed to \u201cfloat\u201d in his words.<\/li>\n<\/ol>\n

    Personally, I also wanted to use less wire and happened to have a length of 42 feet of landscape wire which should work well below 5 MHz with the Wellbrook amp engaged.\u00a0 Results were not bad even though on hard frozen ground. Signal levels were down a little compared to the 100 foot of wire.\u00a0 Here are a couple of examples, first one in a fast food parking lot with a grass field next to it and second at the usual Forest Preserve parking lot on a grass field.\u00a0 I made sure that my car blocked the view of the wire so people would not get nervous!<\/p>\n

    La Voz Missionaria, Brazil:<\/strong><\/p>\nhttps:\/\/archive.org\/download\/20-dec-2020-16h-25m-12s-z-4.724-mhz-usb-hfgcs-alphanumeric\/17-Dec-2020%2002h21m11sZ%2C%209.665%20MHz%2C%20SAM%20-%20RVozMissionaria%20Portuguese%20Camboriu.mp3<\/a><\/audio>\n

    Voice of Welt from Issoudun France in Kurdish:<\/strong><\/p>\nhttps:\/\/archive.org\/download\/20-dec-2020-16h-25m-12s-z-4.724-mhz-usb-hfgcs-alphanumeric\/23-Dec-2020%2021h46m08sZ%2C%209.525%20MHz%2C%20SAM%20VoWelt%20Kurdish%20Issoudun.mp3<\/a><\/audio>\n

    These are not necessarily \u201cDX\u201d but definitely good for SWLing. I like the signal strength with the amplifier inline at the antenna feedpoint and I did not have to use an RF Choke at the receiver side as was suggested.<\/p>\n

    I had a 75 foot long insulated wire and used that at the Forest Preserve parking lot on a couple of different days.\u00a0 Lower frequency signal strength and signal\/noise ratio improved a little bit to be noticeable.<\/p>\n

    US Air Force HFGCS \u201cnumbers\u201d station<\/strong>. Remote controlled from Andrews or Grand Forks bases (https:\/\/en.wikipedia.org\/wiki\/High_Frequency_Global_Communications_System<\/a>), there was no way for me to know which of the 6 transmitters it was coming from:<\/p>\nhttps:\/\/archive.org\/download\/20-dec-2020-16h-25m-12s-z-4.724-mhz-usb-hfgcs-alphanumeric\/20-Dec-2020%2016h25m12sZ%2C%204.724%20MHz%2C%20USB%20-%20HFGCS%20alphanumeric.mp3<\/a><\/audio>\n

    BBC from Tinang Philippines in Korean:<\/strong><\/p>\nhttps:\/\/archive.org\/download\/20-dec-2020-16h-25m-12s-z-4.724-mhz-usb-hfgcs-alphanumeric\/20-Dec-2020%2016h40m26sZ%2C%205.845%20MHz%2C%20SAM%20-%20BBC%20Korean%20Tinang.mp3<\/a><\/audio>\n

    Then, as nanZor suggested in his postings, I purchased a 9:1 balun\/RF choke (it has both a balun and an RF choke built-in) from Ham Radio Outlet<\/a> and put that in place of the Wellbrook amplifier.<\/p>\n

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

    I have not worked with it, but it is reported that the Nooelec.com v2 model is cheaper and works just as well – https:\/\/swling.com\/blog\/2019\/10\/the-nooelec-balun-19-v2\/<\/a><\/p>\n

    Examples below with the 42 foot loop and 9:1 balun\/choke, no amplifier:<\/p>\n

    KSDA, Agat Guam in English<\/strong><\/p>\nhttps:\/\/archive.org\/download\/20-dec-2020-16h-25m-12s-z-4.724-mhz-usb-hfgcs-alphanumeric\/27-Dec-2020%2021h59m59sZ%2C%2011.99%20MHz%2C%20SAM%20KSDA%20English%20Agat.mp3<\/a><\/audio>\n

    WB8U doing a POTA activation of Leavenworth State Fishing Lake<\/strong><\/p>\nhttps:\/\/archive.org\/download\/20-dec-2020-16h-25m-12s-z-4.724-mhz-usb-hfgcs-alphanumeric\/28-Dec-2020%2022h24m00sZ%2C%207.209%20MHz%2C%20LSB%20WB8U%20POTA%20K7390%20Leavenworth%20State%20Fishing%20Lake.mp3<\/a><\/audio>\n

    VOLMET weather, Shannon Ireland<\/strong><\/p>\nhttps:\/\/archive.org\/download\/20-dec-2020-16h-25m-12s-z-4.724-mhz-usb-hfgcs-alphanumeric\/28-Dec-2020%2022h47m46sZ%2C%205.505%20MHz%2C%20USB%20VOLMET%20Shannon%20Ireland.mp3<\/a><\/audio>\n

    HCJB Quito Ecuador, probably in Quechua<\/strong><\/p>\nhttps:\/\/archive.org\/download\/20-dec-2020-16h-25m-12s-z-4.724-mhz-usb-hfgcs-alphanumeric\/28-Dec-2020%2022h59m29sZ%2C%206.05%20MHz%2C%20ECSS-U%20HCJB%20Quito.mp3<\/a><\/audio>\n

    As a side note, there is a posting that mentions low-angle DX is better with regions that have better \u201cground conductivity\u201d, salt water being the best. I have no way of verifying this.\u00a0 See post# 126 by KK5JY Matt<\/a>.<\/p>\n

    So, bottom line is that a Loop on Ground can be useful for pleasant SWLing and portable.\u00a0 Best to use it on grass, not asphalt.\u00a0 The loop amplifier is useful to get signal levels up if you have to use a smaller loop size but the signal\/noise ratio will suffer due to its smaller aperture.\u00a0 And, warning, the public will find a way to trip over the wire no matter where you set it up (I may try putting the wire around my car if I can park on a grass surface and\/or use the gaudiest, brightest neon green or orange wire I can find – they can’t trip over THAT, can they?).<\/p>\n

    TomL<\/p>\n

    \n

    Thanks, Tom, for sharing your update. Obviously, the LoG is working brilliantly. It’s amazing that you got such clear reception from the parking lot of a fast food restaurant.\u00a0 If you were using a vertical instead, I bet signals would have been buried in the noise.\u00a0<\/strong><\/em><\/p>\n

    I can also relate to people tripping over antenna wires. I remember one POTA activation recently (the first activation in this three park run<\/a>) where I intentionally laid my counterpoise on the ground, off a foot path, in the brush and where I couldn’t imagine anyone ever stepping. Ten minutes into the activation and for no reason, someone walked off the path, into the brush, and it snagged them. Maybe I’m just a Ninja level trapper and never realized it!?<\/strong><\/em><\/p>\n

    Thanks again for sharing the results of your LoG, Tom. Inspiring!\u00a0<\/strong><\/em><\/p>\n","protected":false},"excerpt":{"rendered":"

    Many thanks to SWLing Post contributor,\u00a0TomL, who shares the following guest post: Loop on Ground Part 2 by TomL My previous Loop on Ground (LoG) experiment was useful which entailed connecting my Wellbrook loop amplifier to a 100 foot loop of speaker wire in the field at my favorite local Forest Preserve. It really brought […]<\/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":[373,3607,3194,433,3,746,43],"tags":[8750,4342,4358,4359,9042,8074,4126,34,5119],"class_list":["post-47249","post","type-post","status-publish","format-standard","hentry","category-am","category-antennas","category-guest-posts","category-mediumwave","category-news","category-recordings","category-shortwave-radio","tag-field-radio","tag-guest-posts","tag-homebrew","tag-homebrew-mag-loop-antenna","tag-log-antenna","tag-loop-on-ground-antenna","tag-portable-radio","tag-shortwave","tag-toml"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_shortlink":"https:\/\/wp.me\/pn3uc-ci5","jetpack-related-posts":[{"id":55884,"url":"https:\/\/swling.com\/blog\/2023\/02\/loop-on-ground-antenna-part-3-toms-low-noise-low-profile-portable-antenna-evolves\/","url_meta":{"origin":47249,"position":0},"title":"Loop-On-Ground Antenna Part 3: Tom’s low-noise, low-profile, portable antenna evolves","author":"Thomas","date":"February 19, 2023","format":false,"excerpt":"Loop on Ground Antenna Part 3 (using multiconductor wire) by TomL It dawned on me recently, perhaps due to sloppy thinking or unintended distractions, that I never wrote about my modified Loop on Ground (LoG) receive antenna that I use at parks and such.\u00a0 For over a year now, I\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\/2023\/02\/KBSQSL.jpeg?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2023\/02\/KBSQSL.jpeg?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2023\/02\/KBSQSL.jpeg?resize=525%2C300&ssl=1 1.5x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2023\/02\/KBSQSL.jpeg?resize=700%2C400&ssl=1 2x"},"classes":[]},{"id":46931,"url":"https:\/\/swling.com\/blog\/2020\/12\/tom-builds-a-portable-loop-on-ground-antenna\/","url_meta":{"origin":47249,"position":1},"title":"Tom builds a portable Loop-On-Ground antenna","author":"Thomas","date":"December 15, 2020","format":false,"excerpt":"Many thanks to SWLing Post contributor,\u00a0TomL, who shares the following guest post: My First Loop-On-Ground antenna A number of people have mentioned the Loop On Ground (LOG) antenna in the past as a good receive-only antenna.\u00a0 I did some research but could only find a few examples by amateur radio\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\/12\/SignalStrength-e1607948761985.jpg?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2020\/12\/SignalStrength-e1607948761985.jpg?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2020\/12\/SignalStrength-e1607948761985.jpg?resize=525%2C300&ssl=1 1.5x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2020\/12\/SignalStrength-e1607948761985.jpg?resize=700%2C400&ssl=1 2x"},"classes":[]},{"id":31336,"url":"https:\/\/swling.com\/blog\/2018\/03\/backpack-shack-2-0-an-update-from-the-field\/","url_meta":{"origin":47249,"position":2},"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":47496,"url":"https:\/\/swling.com\/blog\/2021\/01\/build-an-affordable-but-stealthy-magnet-wire-vertical-loop-antenna-to-mitigate-condo-qrm\/","url_meta":{"origin":47249,"position":3},"title":"Build an affordable (but stealthy) Magnet Wire Vertical Loop antenna to mitigate condo QRM","author":"Thomas","date":"January 28, 2021","format":false,"excerpt":"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\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\/2021\/01\/MagnetWireVerticalLoop.jpg?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2021\/01\/MagnetWireVerticalLoop.jpg?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2021\/01\/MagnetWireVerticalLoop.jpg?resize=525%2C300&ssl=1 1.5x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2021\/01\/MagnetWireVerticalLoop.jpg?resize=700%2C400&ssl=1 2x"},"classes":[]},{"id":50098,"url":"https:\/\/swling.com\/blog\/2021\/08\/wire-antennas-vs-mag-loop-antennas\/","url_meta":{"origin":47249,"position":4},"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. 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