{"product_id":"radiomaster-dbr4-receiver","title":"RadioMaster DBR4 Dual Band Gemini Xrossband ExpressLRS Receiver, 2.4GHz + 915MHz, CRSF for RC\/FPV","description":"\u003ch2\u003eOverview\u003c\/h2\u003e\u003cp\u003eThe RadioMaster DBR4 is a dual band ExpressLRS receiver designed as a companion to the RadioMaster Nomad module. It is a dual-channel Gemini receiver with two dual-band sections, allowing simultaneous reception of 2.4GHz and sub-GHz (900\/915MHz) signals for receiving two data streams at the same time.\u003c\/p\u003e\u003ch2\u003eKey Features\u003c\/h2\u003e\u003cul\u003e\n\u003cli\u003eGemini Xrossband (Gemini-X \/ GemX) operation (2.4GHz + 900\/915MHz)\u003c\/li\u003e\n\u003cli\u003eDual band diversity\u003c\/li\u003e\n\u003cli\u003eTwo third-generation Semtech LR1121 RF transceivers (Dual LR1121)\u003c\/li\u003e\n\u003cli\u003e4 discrete antennas for flexible antenna placement\u003c\/li\u003e\n\u003cli\u003e20 x 20mm mounting pattern (for adding to a stack or mounting to a frame)\u003c\/li\u003e\n\u003cli\u003eMAVLink ready; optimized for MAVLink\u003c\/li\u003e\n\u003cli\u003eXrossband (GemX) support\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch2\u003eSpecifications\u003c\/h2\u003e\u003ctable\u003e\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eItem\u003c\/td\u003e\n\u003ctd\u003eDBR4 Gemini Xrossband ExpressLRS Receiver\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eType\u003c\/td\u003e\n\u003ctd\u003eISM_2.4, FCC_915 (also listed as ISM 2.4GHz \/ FCC 915MHz)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMCU\u003c\/td\u003e\n\u003ctd\u003eESP32\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eRF chip\u003c\/td\u003e\n\u003ctd\u003eSemtech LR1121 x 2\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTelemetry RF power\u003c\/td\u003e\n\u003ctd\u003eMax 2 x 100 mW (feature text); Max 100 mW (specification)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAntenna\u003c\/td\u003e\n\u003ctd\u003e2 x 2.4GHz wires \u0026amp; 2 x 900MHz wires (also labeled as 2 x 915MHz wire antennas)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFrequency range\u003c\/td\u003e\n\u003ctd\u003e2.404 - 2.479 GHz \/ 903.5 - 926.9 MHz\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMaximum receive refresh rate\u003c\/td\u003e\n\u003ctd\u003e500Hz (1000Hz coming soon in ExpressLRS v3.4)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMinimum receiver refresh rate\u003c\/td\u003e\n\u003ctd\u003e50Hz\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eWorking voltage\u003c\/td\u003e\n\u003ctd\u003eDC 4.5 - 8.4V\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eWeight\u003c\/td\u003e\n\u003ctd\u003eWithout antennas 2.70g (specification); with antennas 5.30g (specification); 2.65g (displayed measurement)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eDimensions\u003c\/td\u003e\n\u003ctd\u003e27.20 x 27.20mm (also listed as 27 x 27mm)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMounting holes\u003c\/td\u003e\n\u003ctd\u003e20 x 20mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFirmware version\u003c\/td\u003e\n\u003ctd\u003eExpressLRS v3.3.2 pre-installed\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBus interface\u003c\/td\u003e\n\u003ctd\u003eCRSF\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAntenna length (as labeled)\u003c\/td\u003e\n\u003ctd\u003e105.20mm; 16.10mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\u003c\/table\u003e\u003cp\u003eFor installation or configuration help, contact \u003ca href=\"https:\/\/rcdrone.top\/\" rel=\"noopener\" target=\"_blank\"\u003ehttps:\/\/rcdrone.top\/\u003c\/a\u003e or email \u003ca href=\"mailto:support@rcdrone.top\"\u003esupport@rcdrone.top\u003c\/a\u003e.\u003c\/p\u003e\u003ch2\u003eNew Packet Rates\u003c\/h2\u003e\u003cp\u003e\u003cstrong\u003eSub-GHz 250Hz (-111dBm)\u003c\/strong\u003e\u003c\/p\u003e\u003cul\u003e\u003cli\u003e\n\u003cstrong\u003eSpeed Boost:\u003c\/strong\u003e Achieve faster packet rates with enhanced sub-GHz performance.\u003c\/li\u003e\u003c\/ul\u003e\u003cp\u003e\u003cstrong\u003eSub-GHz 200Hz Full (-111dBm)\u003c\/strong\u003e\u003c\/p\u003e\u003cul\u003e\u003cli\u003eDouble the packet rate compared to traditional 900MHz SX1276-based modules, with improved resistance to interference.\u003c\/li\u003e\u003c\/ul\u003e\u003cp\u003e\u003cstrong\u003eDual Band X150Hz (-112dBm)\u003c\/strong\u003e\u003c\/p\u003e\u003cul\u003e\u003cli\u003e\n\u003cstrong\u003eGemini Mode:\u003c\/strong\u003e Simultaneous sub-GHz and 2.4GHz transmissions at 150Hz.\u003c\/li\u003e\u003c\/ul\u003e\u003cp\u003e\u003cstrong\u003eDual Band X100Hz Full (-112dBm)\u003c\/strong\u003e\u003c\/p\u003e\u003cul\u003e\u003cli\u003e\n\u003cstrong\u003eEnhanced Gemini Mode:\u003c\/strong\u003e Dual-frequency transmission at 100Hz with full 16 channel resolution.\u003c\/li\u003e\u003c\/ul\u003e\u003ch2\u003eIntroduction of K Modes\u003c\/h2\u003e\u003cp\u003e\u003cstrong\u003eDK500 (Coming in ExpressLRS v3.5)\u003c\/strong\u003e\u003c\/p\u003e\u003cul\u003e\u003cli\u003eNext generation FSK modulation with built-in packet repair (Forward Error Correction). Like FLRC D500, DK500 sends repeat packets to reduce packet loss.\u003c\/li\u003e\u003c\/ul\u003e\u003cp\u003e\u003cstrong\u003eK1000 Full SubGHz (Coming in ExpressLRS v3.5)\u003c\/strong\u003e\u003c\/p\u003e\u003cul\u003e\u003cli\u003e1000Hz on 868\/900MHz, designed for maximum data throughput while remaining stable and responsive in testing.\u003c\/li\u003e\u003c\/ul\u003e\u003ch2\u003eWhat’s Included\u003c\/h2\u003e\u003cul\u003e\n\u003cli\u003e1 x DBR4 Gemini Xrossband ExpressLRS Receiver\u003c\/li\u003e\n\u003cli\u003e2 x 2.4GHz wire antennas\u003c\/li\u003e\n\u003cli\u003e2 x 900MHz wire antennas\u003c\/li\u003e\n\u003cli\u003e1 x CRSF wire\u003c\/li\u003e\n\u003cli\u003e4 x 4mm red vibration dampeners\u003c\/li\u003e\n\u003cli\u003e4 x 3mm black vibration dampeners\u003c\/li\u003e\n\u003cli\u003e1 x Manual card\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch2\u003eManuals \/ Documentation\u003c\/h2\u003e\u003cp\u003eExpressLRS project documentation: \u003ca href=\"https:\/\/www.expresslrs.org\/\" rel=\"noopener\" target=\"_blank\"\u003ehttps:\/\/www.expresslrs.org\/\u003c\/a\u003e\u003c\/p\u003e\u003ch2 id=\"details\"\u003eDetails\u003c\/h2\u003e\u003cdiv class=\"details-gallery\"\u003e\n\u003cimg alt=\"RadioMaster DBR4 dual band Gemini Xrossband ExpressLRS receiver board for 2.4GHz + 915MHz CRSF\" loading=\"lazy\" src=\"https:\/\/rcdrone.top\/cdn\/shop\/files\/RadioMaster-DBR4-Dual-Band-Xross-Gemini-ExpressLRS-Receiver.png?v=1780650063\"\u003e\u003cp\u003eDBR4 is a dual-band Gemini Xrossband ExpressLRS receiver built to receive 2.4GHz and 900\/915MHz links at the same time.\u003c\/p\u003e\n\u003cimg alt=\"Dual Semtech LR1121 RF transceivers used in the DBR4 for 2.4GHz and 900\/915MHz ExpressLRS operation\" loading=\"lazy\" src=\"https:\/\/rcdrone.top\/cdn\/shop\/files\/RadioMaster-DBR4-Dual-Band-Xross-Gemini-ExpressLRS-Receiver_7a45347e-0c3b-418c-af07-fc4df4ee0cb1.png?v=1780650071\"\u003e\u003cp\u003eTwo third-generation Semtech LR1121 transceivers power the dual-band design for Gemini-X and Xrossband use.\u003c\/p\u003e\n\u003cimg alt=\"DBR4 receiver with four discrete wire antennas for flexible 2.4GHz and 900\/915MHz antenna placement\" loading=\"lazy\" src=\"https:\/\/rcdrone.top\/cdn\/shop\/files\/RadioMaster-DBR4-Dual-Band-Xross-Gemini-ExpressLRS-Receiver.jpg?v=1780650078\"\u003e\u003cp\u003eFour discrete antennas make it easy to route and separate 2.4GHz and sub‑GHz elements for cleaner placement on compact builds.\u003c\/p\u003e\n\u003cimg alt=\"DBR4 ExpressLRS receiver mounted on a stack with 20x20mm mounting pattern highlighted\" loading=\"lazy\" src=\"https:\/\/rcdrone.top\/cdn\/shop\/files\/RadioMaster-DBR4-Dual-Band-Xross-Gemini-ExpressLRS-Receiver_656671ad-9f34-4345-b5ac-db8da4500c3c.png?v=1780650086\"\u003e\u003cp\u003eA 20×20mm mounting pattern fits common FPV stacks and frame mounting options.\u003c\/p\u003e\n\u003cimg alt=\"RadioMaster DBR4 CRSF receiver labeled MAVLink ready and optimized for MAVLink data links\" loading=\"lazy\" src=\"https:\/\/rcdrone.top\/cdn\/shop\/files\/RadioMaster-DBR4-Dual-Band-Xross-Gemini-ExpressLRS-Receiver_1f6b885f-b87b-40ff-98bb-86d21ee0f6de.jpg?v=1780650093\"\u003e\u003cp\u003eCRSF output and MAVLink-ready tuning help support reliable telemetry and flight-controller communication.\u003c\/p\u003e\n\u003cimg alt=\"DBR4 Gemini Xrossband ExpressLRS receiver specifications table including voltage, refresh rate and frequencies\" loading=\"lazy\" src=\"https:\/\/rcdrone.top\/cdn\/shop\/files\/RadioMaster-DBR4-Dual-Band-Xross-Gemini-ExpressLRS-Receiver_33686f1b-9b84-4a67-be38-ba89868719f6.png?v=1780650102\"\u003e\u003cp\u003eKey specs at a glance: 4.5–8.4V input, up to 500Hz refresh rate, and dual-band 2.4GHz plus 903–927MHz coverage.\u003c\/p\u003e\n\u003cimg alt=\"Gemini and Xrossband (GemX) mode chart showing RX\/TX antenna use for 2.4GHz, sub-GHz and dual band\" loading=\"lazy\" src=\"https:\/\/rcdrone.top\/cdn\/shop\/files\/RadioMaster-DBR4-Dual-Band-Xross-Gemini-ExpressLRS-Receiver_d4cff175-c682-4654-8307-36e1d1f1e895.jpg?v=1780650109\"\u003e\u003cimg alt=\"ExpressLRS dual-band mode compatibility chart comparing Ranger, Nomad and Bandit packet rates and bands\" loading=\"lazy\" src=\"https:\/\/rcdrone.top\/cdn\/shop\/files\/RadioMaster-DBR4-Dual-Band-Xross-Gemini-ExpressLRS-Receiver_ef384fd1-8aba-4e23-b8d6-cad9e64e70b9.jpg?v=1780650117\"\u003e\u003cimg alt=\"DBR4 receiver on digital scale with 2.65g reading for lightweight FPV installs\" loading=\"lazy\" src=\"https:\/\/rcdrone.top\/cdn\/shop\/files\/RadioMaster-DBR4-Dual-Band-Xross-Gemini-ExpressLRS-Receiver_f1467592-7957-49c9-bcfa-53a467a05a40.jpg?v=1780650125\"\u003e\u003cp\u003eThe receiver weighs about 2.65g without antennas for minimal impact on all-up weight.\u003c\/p\u003e\n\u003cimg alt=\"DBR4 dimensions and antenna lengths: 20mm mounting spacing and wire antennas labeled 105.2mm and 16.1mm\" loading=\"lazy\" src=\"https:\/\/rcdrone.top\/cdn\/shop\/files\/RadioMaster-DBR4-Dual-Band-Xross-Gemini-ExpressLRS-Receiver_316a22f4-c584-4fe5-b062-92e7d24bb5cf.jpg?v=1780650131\"\u003e\u003cimg alt=\"Package contents: DBR4 receiver, 2.4GHz and 915MHz wire antennas, CRSF wire, and vibration dampeners\" loading=\"lazy\" src=\"https:\/\/rcdrone.top\/cdn\/shop\/files\/RadioMaster-DBR4-Dual-Band-Xross-Gemini-ExpressLRS-Receiver_0e728207-30b3-4334-86e2-0bed3dc60b8f.png?v=1780650140\"\u003e\u003cp\u003eIncluded are the DBR4 receiver, 2× 2.4GHz wire antennas, 2× 915MHz wire antennas, a CRSF cable, and vibration dampeners.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"RadioMaster","offers":[{"title":"FCC","offer_id":52965981585632,"sku":"HP0157.0086-1","price":46.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0643\/3210\/3904\/files\/09_ebef4d34-394f-49e4-a427-ff725e7af8c8.jpg?v=1780584426","url":"https:\/\/rcdrone.top\/fr\/products\/radiomaster-dbr4-receiver","provider":"RCDrone","version":"1.0","type":"link"}