Radio/Receivers

Deciphering the Specifications

Another common cause of confusion when shopping for an Radio/Receiver combo is the specifications. There's quite a few of them, and the information presented to you can get quite complex. Not all radios will contain all of the features below, so you'll have to decide what's important for you and fits within your budget.

Adjustible Deadband

All radios have a certain amount of play in the trigger control that does not transmit a signal. However some radios allow this to be adjusted to suit your style of driving.

Adjustible Rate Control/Exponential

Allows you to set how quickly the servo responds when it's close to neutral and close to it's travel limits. For example, you may want the servo to react faster when the trigger is close to neutral and slower when it's close to it's travel limits, or perhaps you want just the opposite. This allows you to set the trigger up in that fashion.

Built-in Charger

If you decide to use recharable batteries in your radio, this is a handy feature to have. It allows you to charge the batteries without removing them from the radio.

Channels

A channel is one "pathway" to the receiver. The receiver has a servo (or an ESC in electric models) connected to it for each channel that controls a particular function. In a two-channel system one channel controls the steering while the other controls the throttle and reverse or braking functions. Three channel systems are also common among many models, and the third channel can control different things depending on the vehicle in question. For example the third channel on the T-Maxx controls forward/reverse gear selection, while on the E-Maxx it allows you to select between two forward gears.

Channel Scanning

A feature that has been brought about thank to DSM technology is channel scanning. Channel scanning take synthesized technology to the next level, eliminating the need to manually change the frequency channel you are operating on. While synthesized technology did wonders for eliminating crystals, you still had to set both the receiver and the radio by using a set of dials. A radio that uses channel scanning searches for an available channel once it’s on and when it finds a free one, grabs it. The process is automatic, and the ultimate in no-hassle radio operation.

Dual Rate

This allow the entire servo throw, from left to right, to be changed. This is not to be confused with end point adjustments though, as it affects both the left and right direction of the servo exactly the same.

End Point Adjustments

This allows you to set the left and right endpoints for the servo independantly of each other. Although more commonly used in nitro applications for the throttle and brake, it still can be very useful when used for the steering in an electric RC application.

Frequency

Radios operate on certain frequencies. There are three ranges you can commonly buy a radio/receiver in, but for cars and trucks only two of those apply. The third range is for planes only. The two ranges are 27 Mhz and 75 Mhz, and those frequencies are divided into numbered channels. Six channels for the 27 Mhz range and 30 channels for the 75 Mhz range. Do not confuse the frequency channels with radio channels, as that is a common mistake. Radio channels control servos and frequency channels control communication from the radio to the receiver.

All pistol grip type radios will be using one of the above channels. If you choose to use a stick-type radio, make sure it is for one of those two ranges, as it can also come set up for the 72 Mhz range which is for aircraft models only. Using the 72 Mhz frequency can cause difficulty for anyone nearby who might be flying a plane, and in most cases a model plane crash can be very costly to the owner. So be considerate of others in the hobby.

Lap Timer

Tracks how long it takes you to complete a lap. Usually controlled by a button that's placed near your thumb where you can easily click it to tell it a lap has been completed and to start timing another one. Different model radio offer different amounts of laps that the radio will store in it's memory for later review.

Low Voltage Alarm

Some radios offer an audible alarm when the batteries reach a certain state of discharge so that you won't lose radio control.

Model Memory

This is the ability for one radio to store the settings and preferences for several different vehicles. This is a handy feature if you plan on using the radio for more than one truck or car.

Programmable Mixing

Allows you to mix one channels adjustments with another. In some applications such as turning a boat, or when using a model with 4-wheel steering, you often want two channels of the radio to act togther. Mixing allows this.

Servo Reversing

The ability to reverse a servo is pretty basic and is standard on just about all radios. If you find that a servo operates opposite of it's intended function, you simply flip a switch and the servo actions are reversed.

Subtrim Adjustment

The ability to have subtrim adjustment is just what it sounds like. It allows you to set the trim even finer than you can with the trim adjustment control. So if a trim adjustment seems to give you too much in one direction or another, the subtrim control would allow you to alter the servo's neutral point with an even finer touch.

Synthesized Signal Processing

The ability to send radio signals without the use of crystals. This is a big benefit as it allows you to use several channels for radio operation to avoid interference with others. A set of crystals can cost $20-30 which adds up quickly. Radios that offer Synthesized Signal Processing give you access to all channels in a particular frequency range, without the need for purchasing extra sets of crystals. When purchasing a radio with this feature, it's preferable to buy one intended for the 75 Mhz range instead of the 27 Mhz range. This is because there are 30 available channels in the 75 Mhz range, while they are only 6 in the 27 Mhz range. So you'll get many more available channels for your money by going with the 75 Mhz range.

Telemetry

Some of the newer DSM radios offer the capability of bringing information back from the truck as opposed to just sending it signals like a standard radio does. This is called telemetry, and can be used for things such as receiver pack voltage and engine temperature. The possibilities are nearly limitless, and this will be one area that will grow rapidly in the next couple of years.

Throttle Deadband

Used to eliminate the deadband, or play, from the neutral position to the point where the servo actually starts applying the throttle or brake.

Trim Adjustment

Often when you install a servo saver or servo horn, it isn't precisely centered. You can use the trim adjustment to fine tune the neutral centerpoint so that centered is truly centered.

Part One:	Introduction
Part Two:	Deciphering the Specifications
Part Three:	Radio Adjustment Tips
Part Four:	Frequency Charts
Part Five:	Recommended Radio/Receiver Combos