{"id":202,"date":"2018-02-08T14:43:44","date_gmt":"2018-02-08T14:43:44","guid":{"rendered":"https:\/\/www.getfpv.com\/learn\/?p=202"},"modified":"2018-03-23T12:25:31","modified_gmt":"2018-03-23T12:25:31","slug":"all-about-multirotor-fpv-drone-radio-transmitter-and-receiver","status":"publish","type":"post","link":"https:\/\/www.getfpv.com\/learn\/new-to-fpv\/all-about-multirotor-fpv-drone-radio-transmitter-and-receiver\/","title":{"rendered":"All About Multirotor Drone Radio Transmitters and Receivers"},"content":{"rendered":"<p><span style=\"font-weight: 400;\">One of the crucial pieces of equipment necessary for flying a multirotor is a FPV Drone Radio Transmitter (Tx) and Radio Receiver (Rx).<\/span><\/p>\n<h2>FPV Drone Radio Transmitters<\/h2>\n<p><span style=\"font-weight: 400;\">An FPV Drone Radio Transmitter is an electronic device that uses radio signals to transmit commands wirelessly via a set radio frequency over to the Radio Receiver, which is connected to an aircraft or multirotor being remotely controlled. In other words, it\u2019s the device that translates pilot\u2019s commands into movement of the multirotor. <\/span><\/p>\n<p><span style=\"font-weight: 400;\">In some radios there is an option to connect an external transmitter module. This \u00a0makes it possible to use a different frequency (for instance, 900MHz in a 2.4GHz radio) or a different receiver from another brand\/protocol (Crossfire CRSF module with Crossfire V2 Micro Receiver in FrSky Taranis).<\/span>[vc_single_image image=&#8221;381&#8243; img_size=&#8221;full&#8221; alignment=&#8221;center&#8221;][vc_column_text]<\/p>\n<h2>Channels<\/h2>\n<p><span style=\"font-weight: 400;\">A\u00a0FPV Drone Radio Transmitter transmits commands via channels. Each channel is an individual action being sent to the aircraft.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Throttle, Yaw, Pitch and Roll are the four main inputs required to control the quad. Each of them \u00a0uses one channel, so there is minimum of four channels required. Every switch, slider or \u00a0knob on the transmitter \u00a0uses one channel to send the information through to the receiver. <\/span><\/p>\n<p><span style=\"font-weight: 400;\">The following is an example of the typical channel setup for FPV Racing: a switch for arming the aircraft, a switch for turning on the buzzer and a switch used to select different flight modes. For this reason, it is advised to have a 6 channel radio.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Basic 4-6 channel radios are usually the cheapest. Radios with more than 6 channels are typically more expensive.<\/span>[\/vc_column_text][vc_row_inner][vc_column_inner][vc_column_text]<\/p>\n<h2>Gimbals<\/h2>\n<p><span style=\"font-weight: 400;\">Gimbals \u00a0are the sticks that translate a pilots input into the digital data transmitted to the radio receiver. <\/span><\/p>\n<p><span style=\"font-weight: 400;\">There are two types of gimbals commonly used :<\/span><\/p>\n<ul>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Hall Effect Gimbal (digital)<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Potentiometer type Gimbal (analogue)<\/span><\/li>\n<\/ul>\n<p><span style=\"font-weight: 400;\">Hall Effect gimbals \u00a0use hall sensors with magnets to capture the stick position values and is therefore more resistant to wear. These gimbals are also more precise.<\/span>[\/vc_column_text][vc_single_image image=&#8221;382&#8243; img_size=&#8221;full&#8221; alignment=&#8221;center&#8221;][vc_column_text]<span style=\"font-weight: 400;\">Potentiometer type gimbals uses a brush to capture the value of stick inputs and is therefore prone to wear out much quicker.<\/span>[\/vc_column_text][vc_single_image image=&#8221;383&#8243; img_size=&#8221;full&#8221; alignment=&#8221;center&#8221;][vc_column_text]<span style=\"font-weight: 400;\">Gimbal sticks are manufactured with M3 or M4 threads which allows you to attach different types of stick ends. Pilots that prefer flying with the \u201cPinch\u201d method might prefer a different type of stick end to \u00a0pilots that prefer flying with their thumbs. In general, sticks are approximately 25-27mm in length. They can be adjusted to suit personal preferences.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Below is an example of the different types of stick ends:<\/span>[\/vc_column_text][vc_single_image image=&#8221;384&#8243; img_size=&#8221;full&#8221; alignment=&#8221;center&#8221;][\/vc_column_inner][\/vc_row_inner][vc_row_inner][vc_column_inner][vc_column_text]<\/p>\n<h2>FPV Drone Radio Transmitter Modes<\/h2>\n<p><span style=\"font-weight: 400;\">When purchasing an FPV Drone Radio Transmitter, you need to determine which \u201cMode\u201d you would prefer to use when flying.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">The mode determines aircraft movement assigned to a certain stick movement. There are 4 transmitter modes with Mode 2 being the most popular and is usually set as the default mode on most radios. <\/span>[\/vc_column_text][vc_single_image image=&#8221;385&#8243; img_size=&#8221;full&#8221; alignment=&#8221;center&#8221;][\/vc_column_inner][\/vc_row_inner][vc_row_inner][vc_column_inner][vc_column_text]<\/p>\n<h2>Frequencies<\/h2>\n<p><span style=\"font-weight: 400;\">An\u00a0FPV Drone Radio Transmitter commonly use the following frequencies: 27MHz, 72MHz, 433MHz, 900MHz, 1.3GHz and 2.4Ghz<\/span><\/p>\n<p><span style=\"font-weight: 400;\">433Mhz, 900Mhz and 1.3GHz are typically used in long range FPV and RC systems. <\/span><\/p>\n<p><span style=\"font-weight: 400;\">27Mhz and 72Mhz are older frequencies which were being used for many years in RC. Equipment operating on those frequencies used crystals to bind the Transmitter with a Receiver. Apart from a few RC toys still available on the market, they are rarely used.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">2.4GHz is most popular frequency. It is a newer technology and it offers \u201cfrequency hopping\u201d which does the job of managing multiple users frequency transmitting at the same time. This id done by scanning the frequency band and finding the best available channel during the transmission. 2.4GHz antennas are very compact as well. Generally speaking the lower the frequency, the larger the antenna. For that reason, 2.4GHz quickly became the \u201cgo to\u201d frequency. <\/span>[\/vc_column_text][\/vc_column_inner][\/vc_row_inner][vc_row_inner][vc_column_inner][vc_column_text]<\/p>\n<h2>Open TX<\/h2>\n<p><span style=\"font-weight: 400;\">OpenTX is an open source custom firmware made for RC radio transmitters, compatible with the following radios: (January 2018)<\/span><\/p>\n<ul>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">FrSky Taranis X9D, Q7X, X9E<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">FrSky Horus X10, X12<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Turnigy 9X<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">FlySky 9X<\/span><\/li>\n<\/ul>\n<p><span style=\"font-weight: 400;\">OpenTX is a highly configurable system offering plenty options for all types of RC models. It is created by FPV pilots with pilots in mind and has frequent updates being released with bug fixes and new features.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">The main features of OpenTX is as follows:<\/span><\/p>\n<ul>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">In flight audio\/speech feedback with custom sounds that are stored on the transmitters Micro SD card<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Can store a large number of models on the radio, even more if stored on the Micro SD card<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Logical switches and special functions used to program custom behaviours on the radio (for instance having a custom audio feedback on low battery voltage or high mAH consumption) <\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">LUA scripts \u2013 a powerful tool used to change the parameters of Video Transmitter or Flight Controller settings directly from the radio without connecting it to a computer<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Allows flashing of radio receivers firmware directly from radio transmitter<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Configurable via OpenTX Companion software where all models, settings and even entire radio transmitter firmware can be copied or backed up on the computer. Companion app can also emulate radio transmitter firmware on the computer<\/span><\/li>\n<\/ul>\n<p>[\/vc_column_text][\/vc_column_inner][\/vc_row_inner][vc_row_inner][vc_column_inner][vc_column_text]<\/p>\n<h2>Telemetry<\/h2>\n<p><span style=\"font-weight: 400;\">Telemetry is the data transmitted from the Radio Receiver back to the Radio Transmitter. <\/span><\/p>\n<p><span style=\"font-weight: 400;\">It usually contain a variety information, depending on the type of radio and flight controller. The most crucial pieces of information are battery voltage reading, current draw and \u201cRSSI\u201d (Radio Signal Strength Indication).<\/span><\/p>\n<p><span style=\"font-weight: 400;\">This Telemetry Data can be displayed on the telemetry screen (in OpenTX), and can also be customised as audio warnings.<\/span>[\/vc_column_text][\/vc_column_inner][\/vc_row_inner][vc_row_inner][vc_column_inner][ultimate_spacer height=&#8221;25&#8243;][vc_separator el_width=&#8221;20&#8243;][ultimate_spacer height=&#8221;25&#8243;][\/vc_column_inner][\/vc_row_inner][vc_row][vc_column][vc_row_inner][vc_column_inner][vc_column_text]<\/p>\n<h2>Radio Receivers<\/h2>\n<p><span style=\"font-weight: 400;\">A Radio Receiver is the device capable of receiving commands from the Radio Transmitter, interpreting the signal via the flight controller where those commands are converted into specific actions controlling the aircraft. <\/span><\/p>\n<p><span style=\"font-weight: 400;\">Radio Receivers can have the following features:<\/span><\/p>\n<ul>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Telemetry (sending data back to transmitter)<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Redundancy function (two receivers connected together, if one loses connection, second one takes over)<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Easy removable antennas (more convenient with connectors if antenna is to be replaced)<\/span><\/li>\n<li style=\"font-weight: 400;\">Possibility of firmware upgrades (for bug fixes)<\/li>\n<\/ul>\n<p>[\/vc_column_text][vc_single_image image=&#8221;386&#8243; img_size=&#8221;full&#8221; alignment=&#8221;center&#8221;][\/vc_column_inner][\/vc_row_inner][vc_row_inner][vc_column_inner][vc_column_text]<\/p>\n<h2>Protocols<\/h2>\n<p><span style=\"font-weight: 400;\">Radio communication protocols can split into two groups:<\/span><\/p>\n<ul>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">TX Protocols between Radio Transmitter and Radio Receiver.<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">RX Protocols between Radio Receiver and Flight Controller<\/span><\/li>\n<\/ul>\n<p>[\/vc_column_text][vc_single_image image=&#8221;387&#8243; img_size=&#8221;full&#8221; alignment=&#8221;center&#8221;][vc_column_text]<span style=\"font-weight: 400;\">TX Protocols are in most cases specific to brands:<\/span><\/p>\n<ul>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">FrSky: D8, D16, LR12<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Spektrum: DSM, DSM2, DSMX<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">FlySky: AFHDS, AFHDS 2A<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Futaba: FASST<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Hitec: A-FHSS<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Devo: Hi-Sky<\/span><\/li>\n<\/ul>\n<p>&nbsp;<\/p>\n<p><span style=\"font-weight: 400;\">As for RX Protocols, some of them are universal:<\/span><\/p>\n<ul>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">PCM, PWM, PPM, SBUS <\/span><\/li>\n<\/ul>\n<p><span style=\"font-weight: 400;\">However, there are also brand specific ones:<\/span><\/p>\n<ul>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">TBS: CRSF Crossfire<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Graupner: SUMD, SUMH<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">FrSky: FPort<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Multiwii: MSP<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Flysky: IBUS<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">JR: XBYUS<\/span><\/li>\n<\/ul>\n<p>&nbsp;<\/p>\n<p><span style=\"font-weight: 400;\">A Receiver must be compatible with the Radio Transmitter which in most cases means that the same brand of Rx and Tx need to be purchased in order to establish a communication. There are however radio receivers that may work with the same protocol but are not from the same brand. <\/span><span style=\"font-weight: 400;\"><br \/>\n<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Frequencies must also be the same on both Rx and Tx. For instance; a 2.4GHz Transmitter can only work with 2.4GHz Radio Receiver. <\/span>[\/vc_column_text][\/vc_column_inner][\/vc_row_inner][vc_row_inner][vc_column_inner][vc_column_text]<\/p>\n<h2>Binding<\/h2>\n<p><span style=\"font-weight: 400;\">A Radio Transmitter will only communicate with a Radio Receiver if the two are binded. This process might differ on specific receivers and radios. Usually, this can be done by starting the bind process on the Radio and pressing BIND button on the receiver. The best would be to refer to the user manual of your specific Rx and Tx combo.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">It\u2019s important to note that a single Radio Transmitter can be bound to multiple different Receivers. At the same time, a single receiver can only be bound to a single transmitter, not multiple transmitters.<\/span>[\/vc_column_text][\/vc_column_inner][\/vc_row_inner][vc_row_inner][vc_column_inner][vc_column_text]<\/p>\n<h2>Radio Receiver Antennas<\/h2>\n<p><span style=\"font-weight: 400;\">Receiver antennas are usually soldered directly to the receiver main board or attached by U.FL connectors. Antennas are made from a coax cable where the main wire is separated from \u201cground\u201d. Radio Receivers are usually manufactured with two antennas to ensure the best reception.<\/span>[\/vc_column_text][vc_column_text]<span style=\"font-weight: 400;\">The main wire is the antenna active element which receives radio signals via a specific frequency. Length of the active element depends on the frequency and is exactly 1\/4th of the wavelength for a specific frequency. Length of the antenna wire is not fixed; only active elements has to be at specific length. As am example, the wavelength for 2.4GHz transmission is 122mm. 1\/4th of that equates to 30.5mm for the active element.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Receivers usually come with two antennas for 2.4GHz Frequency. To achieve the best signal reception it is recommended to keep them at a 90degree angle in relation to each other when installed on the multi rotor.<\/span>[\/vc_column_text][\/vc_column_inner][\/vc_row_inner][vc_row_inner][vc_column_inner][vc_column_text]<\/p>\n<h2>Radio Receiver Sizes<\/h2>\n<p><span style=\"font-weight: 400;\">Radio receivers come in a different sizes and shapes. <\/span><\/p>\n<p><span style=\"font-weight: 400;\">Smaller receivers usually have molex connectors while bigger ones have pins soldered on. Smaller receivers are more convenient for smaller multirotors where mounting options for hardware is very limited.\u00a0Bigger receivers with pins can be used in more spacious multirotor builds.<\/span>[\/vc_column_text][vc_single_image image=&#8221;388&#8243; img_size=&#8221;full&#8221; alignment=&#8221;center&#8221;][\/vc_column_inner][\/vc_row_inner][\/vc_column][\/vc_row][vc_row][vc_column][ultimate_spacer height=&#8221;25&#8243;][vc_separator el_width=&#8221;20&#8243;][ultimate_spacer height=&#8221;25&#8243;][\/vc_column][\/vc_row][vc_row][vc_column][vc_column_text]<\/p>\n<h2>Conclusion<\/h2>\n<p><span style=\"font-weight: 400;\">When selecting your\u00a0FPV Drone Radio Transmitter and Receiver, it is important to confirm that they are compatible not just with each other, but also has the necessary size and features for your specific needs. It is recommended to purchase a high quality Radio Transmitter when starting out to fly FPV as it is one of the components that will last you the longest in this hobby.<\/span>[\/vc_column_text][ultimate_spacer height=&#8221;25&#8243;][dt_default_button link=&#8221;url:https%3A%2F%2Fwww.getfpv.com%2Fradios.html||target:%20_blank|&#8221; size=&#8221;medium&#8221; btn_width=&#8221;btn_full_width&#8221; button_alignment=&#8221;btn_center&#8221;]PURCHASE YOUR FPV DRONE RADIO TRANSMITTER AND RECEIVER HERE[\/dt_default_button][\/vc_column][\/vc_row][vc_row][vc_column][vc_column_text]<\/p>\n<p>[\/vc_column_text][\/vc_column][\/vc_row]<\/p>\n","protected":false},"excerpt":{"rendered":"<p>One of the crucial pieces of equipment necessary for flying a multirotor is a FPV Drone Radio Transmitter (Tx) and Radio Receiver (Rx). FPV Drone Radio Transmitters An FPV Drone Radio Transmitter is an electronic device that uses radio signals to transmit commands wirelessly via a set radio frequency over to the Radio Receiver, which &#8230; <a title=\"All About Multirotor Drone Radio Transmitters and Receivers\" class=\"read-more\" href=\"https:\/\/www.getfpv.com\/learn\/new-to-fpv\/all-about-multirotor-fpv-drone-radio-transmitter-and-receiver\/\" aria-label=\"Read more about All About Multirotor Drone Radio Transmitters and Receivers\">Read more<\/a><\/p>\n","protected":false},"author":2,"featured_media":203,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-202","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-new-to-fpv","infinite-scroll-item","generate-columns","tablet-grid-50","mobile-grid-100","grid-parent","grid-33"],"_links":{"self":[{"href":"https:\/\/www.getfpv.com\/learn\/wp-json\/wp\/v2\/posts\/202","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.getfpv.com\/learn\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.getfpv.com\/learn\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.getfpv.com\/learn\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.getfpv.com\/learn\/wp-json\/wp\/v2\/comments?post=202"}],"version-history":[{"count":14,"href":"https:\/\/www.getfpv.com\/learn\/wp-json\/wp\/v2\/posts\/202\/revisions"}],"predecessor-version":[{"id":1274,"href":"https:\/\/www.getfpv.com\/learn\/wp-json\/wp\/v2\/posts\/202\/revisions\/1274"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.getfpv.com\/learn\/wp-json\/wp\/v2\/media\/203"}],"wp:attachment":[{"href":"https:\/\/www.getfpv.com\/learn\/wp-json\/wp\/v2\/media?parent=202"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.getfpv.com\/learn\/wp-json\/wp\/v2\/categories?post=202"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.getfpv.com\/learn\/wp-json\/wp\/v2\/tags?post=202"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}