More Information on Radios

 

If you are new to hobby grade radio controlled vehicles, then you are probably also unfamiliar with the radio systems that are used to control them. That’s okay, because this is where you’ll find information that will make you familiar with some basic terms and concepts about them.

 

The Radio- Also known as the transmitter or the controller. This is the device you use to control your car, truck, plane, boat, or any other type of vehicle. Like a miniature radio station, it sends radio signals out that tell the vehicle what to do.

 

The receiver- As the name suggests this is what receives the radio signals that the transmitter sends out. The receiver then tells the equipment onboard the vehicle what to do. This equipment includes things like servos and Electronic Speed Controllers (ESC for short).

 

Servos- These are one of the things that a receiver can control. They act like robotic arms, able to push and pull on a variety of things such as the mechanisms that make a car steer or a throttle on a nitro engine. With some modifications we will make a servo turn all the way around, instead of just a limited distance.

 

Radio Modulation- All this refers to is the method the radio uses to send information in the radio waves. All you need to be aware of for now is the difference between AM and FM. AM stands for Amplitude Modulation. This simply means that radio increases and decrease the strength (amplitude) of the signal in order to send information. FM stands for Frequency Modulation. This means the radio slightly changes the pitch (frequency) of the signal to send information. There are more types of systems out there too, but just knowing about AM and FM should be sufficient to start.

          For a beginner starting out in RC, an inexpensive AM system will work fine. Later on you can upgrade to a FM system that will offer more features and a radio signal less prone to interference.

 

Frequency Channels- This refers to specific frequency that a radio system operates at. There are numbers that go with each frequency range and every group has a specific use. This way many people can operate their models at the same time without interfering with each other.

 

27 Megahertz- for all types of models (typically for surface use)

          Channels numbers A1 through A6

          Frequencies 26.995 MHz through 27.255 MHz

72 Megahertz- for aircraft use only

          Channel numbers 11 through 60

          Frequencies 72.010 MHz through 72.990 MHz

75 Megahertz- for surface vehicles only

          Channel numbers 61 through 90

          Frequencies 75.410 MHz through 75.990 MHz

 

Control Channels- These are separations in the specific frequency your radio uses that allows different functions to happen. Most radio controlled cars use a two channel system. That allows for two functions (forward/reverse speed and steering) to be controlled separately of each other. Other systems may have 3 or more channels available to them. This allows for more things on a model (such as gear changing, lights, etc.) to be controlled without affecting any other.

          For this project two channels are all that will be needed. One channel to control the right track and one to control the left.

 

Trim adjust- these are what you use to change the position of neutral on the radio. For example, if your car won’t drive straight when the steering control is centered, you use a trim knob (or a slider for stick radios) to correct this. By moving the trim left or right, you can make small adjustments to where the servo sits when centered (at neutral).