{"id":63630,"date":"2025-08-13T07:35:36","date_gmt":"2025-08-13T11:35:36","guid":{"rendered":"https:\/\/swling.com\/blog\/?p=63630"},"modified":"2025-08-13T07:32:55","modified_gmt":"2025-08-13T11:32:55","slug":"building-an-swl-chimera","status":"publish","type":"post","link":"https:\/\/swling.com\/blog\/2025\/08\/building-an-swl-chimera\/","title":{"rendered":"Building an SWL Chimera"},"content":{"rendered":"

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

By Sam (WN5C)<\/strong><\/p>\n

Picture this: a cool July evening on the northern shores of Lake Huron, the water gently lapping on the beach. Feet being warmed by a smoldering fire with crystal clear skies and the Milky Way brilliantly displayed overhead. Radio in my lap, hastily deployed 20-meter vertical antenna in the sand, and zero RFI. Radio New Zealand coming in strong, and SSB contacts between Scotland and Australia sounding local. I\u2019ve never felt so connected to the electromagnetic spectrum. The radio? Surprisingly, a cheap ATS-20+ from AliExpress.<\/p>\n

I\u2019ve been curious about the radios built around the si4732 chip for a while and purchased an ATS-20+<\/a> [affiliate link]<\/em> to throw in my pack to try out. It\u2019s pretty good (and cheap!), especially after flashing the firmware by Goshante<\/a>. With a long wire it does well on HF (I carry 30 feet with a BNC connector) and even better on my dipole at home or a full-sized vertical. The UI is clunky but after some practice gets better. For my family trip to Michigan and the shore of Lake Huron it was a lot easier to just pull this out to listen versus setting up my transceiver and I\u2019m glad I did, there\u2019s a beautiful simplicity in passively taking in whatever the ether sends my way.<\/p>\n

I\u2019m sold on the idea of these cheap general coverage receivers. Sure, they\u2019re not as good as a radio with a real RF front end (gulp), but they\u2019re more than toys. A perfect middle ground for tinkering.<\/p>\n

And there are a lot of variations! In past few months one variety, the mini (it\u2019s called many names), caught my attention. I purchased the AMNVOLT V3S<\/a> version from AliExpress before my Michigan trip, and it was in the mailbox when I arrived home. New versions come out every couple of months but for the project described below it doesn\u2019t matter the version, here\u2019s something similar<\/a> [affiliate link]<\/em>. It\u2019s tiny, but it\u2019s not a Belka, and does best with FM and AM broadcast stations on the small whip. The advantage that this little guy has over the ATS-20+ is a much more capable microcontroller (an ESP32 versus an Arduino Nano) and a beautiful 1.9-inch color display. The included firmware is fine, but there is an active development community that makes it better. I\u2019ve been using Max Arnold\u2019s v2.30 firmware<\/a>. This firmware has lots of features, but some of the standouts include being able to download shortwave schedules to display what you\u2019re listening to and a lot of display customization.<\/p>\n

But I wasn\u2019t too impressed with the hardware design for my purposes. My version has a high-impedance RF amp for the whip and would overload with my dipole at home. The audio wobbles when touching the base of the antenna. The speaker is tiny and tinny. And, although the size is super novel I like using big antennas so the scale seems out of whack. Some of these design limitations have been addressed by Peter Neufeld<\/a> (particularly addressing the wobble). But I decided to pursue a different route.<\/p>\n

I stumbled upon a video by ElectroBananas on Youtube<\/a> where he lays out, in exacting detail, how to create a hybrid of the ATS-20+ and the si4732 mini radio. The wiring isn\u2019t difficult, and he even provides the design for a new front panel to 3D print.<\/p>\n

\"\"<\/a>The advantage of combining these radios is that I have the better-designed RF front end of the ATS-20+, the powerful ESP32 microcontroller and the beautiful display of the mini, and the big speaker\/audio\/battery of the ATS-20+. While I was in there I also added some protection diodes (two back-to-back 2N4148s) to the antenna input. What\u2019s fun is that I added a \u201cbail\u201d using a single mini laptop stand<\/a> [affiliate]<\/em> and changed the display to an orange theme. It looks like a miniature version of my Icom IC-703 (and in A-B tests they\u2019re not too far off). It\u2019s the best of both worlds. And it\u2019s still very small, a perfect bedside radio, or one to carry to the beach.<\/p>\n

\"\"<\/a>The combination of cheap hardware with open-source software development is creating a very exciting time in radio, and I look forward to see what emerges in the months ahead.<\/p>\n

\"\"<\/a>Until then, I wonder if I could fit a low-powered CW transmitter in the case\u2026<\/p>\n","protected":false},"excerpt":{"rendered":"

By Sam (WN5C) Picture this: a cool July evening on the northern shores of Lake Huron, the water gently lapping on the beach. Feet being warmed by a smoldering fire with crystal clear skies and the Milky Way brilliantly displayed overhead. Radio in my lap, hastily deployed 20-meter vertical antenna in the sand, and zero […]<\/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":[8,3194,627,139,43],"tags":[4105,149,9284,10873,9226,10874,10872],"class_list":["post-63630","post","type-post","status-publish","format-standard","hentry","category-articles","category-guest-posts","category-how-to","category-radio-modifications","category-shortwave-radio","tag-how-to","tag-mods","tag-radio-mods","tag-sam-wn5c","tag-si4732","tag-si4732-radios","tag-swl-chimera"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_shortlink":"https:\/\/wp.me\/pn3uc-gyi","jetpack-related-posts":[{"id":49583,"url":"https:\/\/swling.com\/blog\/2021\/07\/the-new-ats-25-si4732-receiver-with-color-touch-screen\/","url_meta":{"origin":63630,"position":0},"title":"The new ATS-25 Si4732 receiver with color touch screen","author":"Thomas","date":"July 9, 2021","format":false,"excerpt":"Many thanks to SWLing Post contributor, Robert Richmond, who writes: An ATS-25 receiver has appeared on eBay and similar sites. It appears to be a touchscreen and user interface update to the previous ATS-20 model. I suppose it remains to be seen if there are any improvements to the underlying\u2026","rel":"","context":"In "New Products"","block_context":{"text":"New Products","link":"https:\/\/swling.com\/blog\/category\/new-products\/"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2021\/07\/ATS-25.jpeg?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2021\/07\/ATS-25.jpeg?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2021\/07\/ATS-25.jpeg?resize=525%2C300&ssl=1 1.5x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2021\/07\/ATS-25.jpeg?resize=700%2C400&ssl=1 2x"},"classes":[]},{"id":48378,"url":"https:\/\/swling.com\/blog\/2021\/04\/any-thoughts-on-this-inexpensive-si4732-based-receiver\/","url_meta":{"origin":63630,"position":1},"title":"Any thoughts on this inexpensive Si4732-based receiver?","author":"Thomas","date":"April 2, 2021","format":false,"excerpt":"I've received a number of inquiries from SWLing Post readers lately regarding an inexpensive Si4732-based mini stand-alone receiver being sold on Amazon and eBay for around $56-66 US shipped. The radio is based on the Silicon Labs Si4732 DSP chip which provides the following frequency coverage: FM (64\u2013108 MHz) with\u2026","rel":"","context":"In "Mediumwave"","block_context":{"text":"Mediumwave","link":"https:\/\/swling.com\/blog\/category\/mediumwave\/"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2021\/04\/Si4732-1.jpeg?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2021\/04\/Si4732-1.jpeg?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2021\/04\/Si4732-1.jpeg?resize=525%2C300&ssl=1 1.5x"},"classes":[]},{"id":50115,"url":"https:\/\/swling.com\/blog\/2021\/08\/kevins-ats-25-video-series\/","url_meta":{"origin":63630,"position":2},"title":"Kevin’s ATS-25 video series","author":"Thomas","date":"August 31, 2021","format":false,"excerpt":"Many thanks to SWLing Post contributor, Robert Richmond, who shares the following series of videos about the new ATS-25 receiver (mentioned in this previous post) from Kevin O'Reilly's YouTube channel. The ATS-25 - A First Look: https:\/\/youtu.be\/smPUBodXLzc ATS-25 First Power Up: https:\/\/youtu.be\/WDuCdpqlGfs ATS-25 Useful Features: https:\/\/youtu.be\/BtrWZrgI15g","rel":"","context":"In "New Products"","block_context":{"text":"New Products","link":"https:\/\/swling.com\/blog\/category\/new-products\/"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2021\/08\/ATS-25-1.jpeg?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2021\/08\/ATS-25-1.jpeg?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2021\/08\/ATS-25-1.jpeg?resize=525%2C300&ssl=1 1.5x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2021\/08\/ATS-25-1.jpeg?resize=700%2C400&ssl=1 2x"},"classes":[]},{"id":52706,"url":"https:\/\/swling.com\/blog\/2022\/05\/daves-updated-ats-25-review\/","url_meta":{"origin":63630,"position":3},"title":"Dave’s updated ATS-25 review","author":"Thomas","date":"May 11, 2022","format":false,"excerpt":"Many thanks to SWLing Post contributor, Dave Zantow (N9EWO), who notes that he has posted an updated review of the ATS-25 Si4732 receiver with the 4.0 firmware revision. Click here to check out his review!","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\/2021\/07\/ATS-25.jpeg?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2021\/07\/ATS-25.jpeg?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2021\/07\/ATS-25.jpeg?resize=525%2C300&ssl=1 1.5x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2021\/07\/ATS-25.jpeg?resize=700%2C400&ssl=1 2x"},"classes":[]},{"id":51288,"url":"https:\/\/swling.com\/blog\/2021\/12\/the-gift-that-keeps-on-giving-pavels-amazing-upcycled-hombrew-radios\/","url_meta":{"origin":63630,"position":4},"title":"The Gift That Keeps On Giving: Pavel’s Amazing Upcycled Hombrew Radios!","author":"Thomas","date":"December 20, 2021","format":false,"excerpt":"Many thanks to SWLing Post contributor, Pavel Kraus, who shares the following guest post: Inspiration for gifts by Pavel Kraus This article should be just an inspiration for how to make a gift for our wives and neighbors so that they are not upset that we are still sitting at\u2026","rel":"","context":"In "Guest Posts"","block_context":{"text":"Guest Posts","link":"https:\/\/swling.com\/blog\/category\/guest-posts\/"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2021\/12\/radio-FM-Iomega-ZIP2-1.jpeg?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2021\/12\/radio-FM-Iomega-ZIP2-1.jpeg?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2021\/12\/radio-FM-Iomega-ZIP2-1.jpeg?resize=525%2C300&ssl=1 1.5x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2021\/12\/radio-FM-Iomega-ZIP2-1.jpeg?resize=700%2C400&ssl=1 2x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2021\/12\/radio-FM-Iomega-ZIP2-1.jpeg?resize=1050%2C600&ssl=1 3x"},"classes":[]},{"id":11918,"url":"https:\/\/swling.com\/blog\/2015\/01\/two-strategies-to-improve-sangean-ats-909x-sensitivity\/","url_meta":{"origin":63630,"position":5},"title":"Two strategies to improve Sangean ATS-909X sensitivity","author":"Thomas","date":"January 14, 2015","format":false,"excerpt":"SWLing Post contributor, Moshe, writes: \"I would like to share something I noticed about Sangean sensitivity issue: As I own the ATS909, I noticed that with fresh set of regular batteries (1.5V) or it's power transformer, it is very sensitive. When the voltage of the batteries drops, so does sensitivity!\u2026","rel":"","context":"In "How To"","block_context":{"text":"How To","link":"https:\/\/swling.com\/blog\/category\/how-to\/"},"img":{"alt_text":"ATS-909X","src":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2014\/07\/ATS-909X.jpg?resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2014\/07\/ATS-909X.jpg?resize=350%2C200 1x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2014\/07\/ATS-909X.jpg?resize=525%2C300 1.5x"},"classes":[]}],"jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/swling.com\/blog\/wp-json\/wp\/v2\/posts\/63630","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=63630"}],"version-history":[{"count":1,"href":"https:\/\/swling.com\/blog\/wp-json\/wp\/v2\/posts\/63630\/revisions"}],"predecessor-version":[{"id":63635,"href":"https:\/\/swling.com\/blog\/wp-json\/wp\/v2\/posts\/63630\/revisions\/63635"}],"wp:attachment":[{"href":"https:\/\/swling.com\/blog\/wp-json\/wp\/v2\/media?parent=63630"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/swling.com\/blog\/wp-json\/wp\/v2\/categories?post=63630"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/swling.com\/blog\/wp-json\/wp\/v2\/tags?post=63630"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}