{"id":593070,"date":"2026-08-23T01:20:13","date_gmt":"2026-08-23T01:20:13","guid":{"rendered":"https:\/\/www.newsbeep.com\/il\/593070\/"},"modified":"2026-08-23T01:20:13","modified_gmt":"2026-08-23T01:20:13","slug":"open-source-expresslrs-receiver-reaches-for-range","status":"publish","type":"post","link":"https:\/\/www.newsbeep.com\/il\/593070\/","title":{"rendered":"Open-Source ExpressLRS Receiver Reaches For Range"},"content":{"rendered":"

Drone control links are, from a radio signals perspective, nothing short of amazing: using a transmitter capable of transmitting, at most, one watt, a protocol such as ExpressLRS (ELRS) can control a drone over 100 kilometers away. [Stan], who has been building a drone electronics stack from scratch, recently designed four ELRS receivers<\/a> and went over the principles behind their incredible range.<\/p>\n

Up to a certain point, the simplest way to increase a radio\u2019s range is to lower the frequency; lower radio frequencies penetrate better through most materials and don\u2019t attenuate as quickly with distance. However, although ELRS can use 900 MHz bands, [Stan]\u2019s receivers primarily use 2.4 GHz. The major improvement is in modulation: unlike other control protocols, which mostly use frequency modulation, or Wi-Fi, which uses phase and amplitude modulation, ELRS uses Chirp Spread Spectrum modulation. This has a low data rate, but it\u2019s very reliable; every bit is transmitted as a chirp \u2013 a linearly rising radio tone \u2013 and the data is encoded in the chirp\u2019s starting frequency. To decode this, the receiver multiplies it with an inverse chirp, then takes a fast Fourier transform, revealing the starting frequency. This process has an equivalent gain of 24 dB, which is enough to let it decode signals even below the receiver\u2019s noise floor.<\/p>\n

The hardware [Stan] designed<\/a> to implement this was comparatively simple, just an ESP32 microcontroller, an SX1281 radio chip, and a few peripherals. All four receivers worked in 2.4 GHz, but two had additional 900 MHz antennas. Against RF design convention, one of the receivers used a via to connect the antenna. This would normally cause a significant impedance mismatch, but since there were enough ground-plane vias nearby, the current return path was barely affected; the receiver\u2019s performance hardly changed. In one test, all four receivers maintained a connection at more than five kilometers, despite a forest blocking the signal\u2019s path.<\/p>\n

We previously covered<\/a> ExpressLRS when it was still an emerging technology. To get this kind of range, it builds on LoRa technology, which has reached<\/a> some impressive distance records<\/a>.<\/p>\n

Thanks to [Keith Olson] for the tip!<\/p>\n","protected":false},"excerpt":{"rendered":"Drone control links are, from a radio signals perspective, nothing short of amazing: using a transmitter capable of…\n","protected":false},"author":2,"featured_media":593071,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[6],"tags":[85,46,125],"class_list":["post-593070","post","type-post","status-publish","format-standard","has-post-thumbnail","category-technology","tag-il","tag-israel","tag-technology"],"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/posts\/593070","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/comments?post=593070"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/posts\/593070\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/media\/593071"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/media?parent=593070"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/categories?post=593070"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/tags?post=593070"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}