Before building your quadcopter, the RC Transmitter would probably be the first few things you need to look at. It’s a common question for RC beginners how to choose a decent RC transmitter. In this article I will discuss the basics of a RC transmitter and what you should buy.
Unlike other parts there isn’t much room for you to DIY, so it’s common that we would just buy a commercially available transmitter. There are a few things about functionality you should know before discussing the price, number of channels, modes, frequency and other features.
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You might have already heard the term Channel when talking about RC transmitters. Each channel allows one individual thing on the aircraft to be controlled. For example, one channel for throttle, one channel for turning right and left, one channel for pitching forward and backward, one for rolling left and right. Four channels is a minimum for a quadcopter (pitch, roll, throttle, yaw).
With more channels than just four, you can even have switch, or potentiometers to change settings on the quadcopter while flying. Some fly controllers (e.g. Multiwii, Arducopter) recommend using transmitters that has at least 5 channels, the extra channel is to switch between different flying modes.
There are basic 4 or 5 Channel, which can has Throttle, Rudder, Ailerons, Elevator. 5 channel has an additional AUX Switch. These are the minimum transmitter you can get for flying a multicopter. They are less expensive but lacking features.
For 6 or more channel, you get more AUX, some even come with potentiometer, 3 position swtich and other great features. They are more expensive radios transmitter, but they do have nicer gimbals, maybe better resolution.
This is a radio controller gimbal. (not the camera gimbal )
There are 2 different Modes – mode one and mode two. It’s basically different control configuration.
The mode one configuration has the elevator control on the left joystick and the throttle on the right one.
The mode two is the most common for quadcopter because the stick represents the movement of your quadcopter. It has the elevator control on the right joystick and the motor throttle on the left one. The right joystick self centres in the both axis, whereas the left joystick only self centres in left/right axis and “clicks” in the up/down axis in order to allow the throttle setting.
There are two main frequencies we use for radio transmitter, 72Mhz and 2.4Ghz.
72 MHZ has been around a long time (decades), it allows longer range, but you can interfere with others using the same frequency (even with different brand)
2.4 GHZ is a newer one, and it’s currently the most common frequency. You get a shorter antenna, but usually shorter range than the 72Mhz. Another good thing is you can usually get away flying with other people, who are using 2.4Ghz as well, but different brands transmitter module.
RC Transmitter and Receiver Paring
A receiver usually comes with the transmitter when you buy it. But be aware that some types of transmitter are only compatible to their own receivers (same brand same model). That means when the receiver is broken you will have to get the same one. There are a few exceptions that they can be paired with other receivers (i think universal is the word?). Make sure you check and ask the shop before buying.
What RC transmitter should I get?
The price range is huge, from as cheap as $20 to over $1000. Of course the cheaper, the lower quality it would be, and the fewer channels you are going to get. It would be a good idea to get a cheap 5 or 6 channel one to get a taste of flying a plane, and later on upgrade to a better transmitter when you know more about the subject. It’s always a good idea to have backup transmitters anyway. However if you are serious about quadcopters and someday want to get one with GPS navigation, gimbal control etc, it’s better to get 8 or more channels.
The transmitter is potentially a long term investment. If you are not sure about whether you will be staying in this hobby, you would be safe to get something like a cheap 6 channel. But if you are sure you will stay in the next couple of years you will not regret to get a 8 channel or more! Moreover It’s not just a matter of number of channels. Some RC transmitters support programming and firmware flashing to enhance functionality as well. So do your research before spending good money on it.
There are a lot more to consider when it comes to choosing a good transmitter, such as the display screen, how the stick feels, Multiple Model Memories and Training features (Buddy mode).
Some radio transmitters come with a useful feature called Expo, it gives you more precise control but still lets you use the full range (although I don’t personally use it).It’s an exponential curve and makes the stick softer around mid-stick.
Recommedation on 8 Channel RC Controller
For a low budget build, Turnigy 9X is not super expensive, and has room for many DIY/Upgrade modifications! See my review about this Transmitter. It’s cheap and allows many DIY modifications.
If you have enough budget, go get the Frsky Taranis, you won’t need to upgrade again for years.
DIY RC Transmitter
Although it’s possible to hack a game console and make your own RC transmitter, it seems quite difficult.
I actually also built a RC Transmitter myself although I haven’t tested it yet with a quadcopter.