The Radio System


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The Basic Radio System

There are many modern radio systems from which the beginner can choose. There are several common brands including Futaba, Airtronics, JR, Hitec, and Multiplex. Each of these offers a wide range of options from a simple 2 - channel up to a computer assisted 14 - channel system! The buyer is limited only by his budget. A beginner should discuss his choice of systems with his intended instructor. There are several reasons for doing this, the primary reason being that the student's systems must be compatible with the instructor's system if it will be used as a buddy box. This issue will be covered in more detail later. This document will cover the basic four channel radio typically used by the beginner.

All basic radio systems consist of four (4) basic components.

Transmitter	The unit which takes the input from the user through the gimbals or sticks, encodes it, and sends it to the aircraft
Receiver	The unit that receives the signal, decodes it, and routes it to the appropriate servo
Servos	The device that converts the decoded signal to mechanical force to operate a control surface
Batteries	The device that provides power for the other devices to operate

There are specific frequencies assigned by the Federal Communications Commission (FCC) for use with airborne R/C models. A beginner must ensure that the system that he chooses is tuned to one of these frequencies. Most radio system manufacturers place a sticker on the outside of the carton that says, "For airborne use only". There is frequency reference chart available that lists the purposes of all of the frequencies that are assigned for R/C use.

The radio that is chosen must meet the 1991 specifications for narrow band receivers. The beginner need not know the actual requirements of these specifications because the systems are required to be certified to this standard. The owner's manual for the system will note that the requirements are met and many of the transmitters and receivers will have a gold sticker to signify this fact.

The radio system may transmit and receive on either an AM frequency or a FM frequency. The FM frequencies are less prone to interference than the AM frequencies although those using AM frequencies seldom have problems with interference. Some radio systems use an internal system, called PPM or PCM, to help to nullify interference.

Regardless of the brand of system, the number of channels, or the price, all transmitters have the same basic components. Transmitters may have additional switches, slides, and displays depending on the functions they perform but the basic components remain the same.


	Typical Transmitter

Antenna	The telescoping tube that transmits the signal
Batteries	The device that provides power to the transmitter
Battery Meter	The device used to monitor the strength of the transmitter batteries
Crystal	The device that sets the radio frequency of the transmission
Gimbals (Stick)	The device that allows the user to input desired control movements into the transmitter
Handle	The device for carrying the transmitter
Power Switch	The switch used to apply battery power to the internal components of the transmitter
Trainer Switch	The switch used to allow an instructor to give control of a model to the student
Trim Lever	Slides used to adjust control surfaces during flight


	There are two (2) primary modes of operation, meaning the way the gimbals are set up for operation. There are unsettled debates as to which mode is the easiest to use and best for a beginner. The modes of operation have become switched between the United States and most European countries. Mode I is primarily used in Europe while Mode II is used in the United States.




		Mode I Mode I started in the days of reed actuated proportional systems. The transmitters were uniformly set up in this manner. The thought was that the elevator and rudder or ailerons were the primary controls and each should be operated by an opposite hand for precision control. Later this carried over into the more modern proportional systems since this was the mode used by most modelers.



	Mode II In later years, the thinking changed to the Mode II configuration. More modelers believed that it was easier to control the primary surfaces effectively with the same hand. Mode II grew in popularity and is used almost exclusively in the USA. A beginner does not have to be concerned about which mode he should select since most manufacturers install the gimbals according the most widely used mode for the nation to which the radio system is being shipped. There have been discussions over the years involving the number of channels with which a beginner should start. Some people say that only three (3) channels should be used; rudder, elevator, and throttle. The argument here is that it is easier for a beginner to only be concerned with using the rudder to make turns and not be concerned with the ailerons. Others contend that four (4) channels should be used; rudder, ailerons, elevator, and throttle. The contention in this argument is that by not using ailerons, a beginner must go through a second phase of beginner training that being learning how to use ailerons. A 4 – channel system offers better control of the model during takeoffs and landings in cross wind conditions. The 4 – channel approach to training is more widely accepted today. A beginner might consider buying one of the more advanced six (6) channel systems to get some of the features that are not available in the basic system such as dual rate controls and exponential. This feature allows the user to reduce the sensitivity of the sticks thereby reducing the chance of over controlling. If the beginner is relatively sure of future goals that involve the use of a six (6) channel system, he can consider this an investment in his future modeling and therefore save money. A lot must be determined before the initial purchase and should be discussed at length with experienced modelers, especially the intended instructor, before the purchase is made. All of the following recommended radios can be purchased at our local hobby shop (Extreme Hobbies) 717-284-0164 Tell them that you were referred by the Buck RC Club web site!

Basic Radios

NAME	SUPPLIER	DESCRIPTION
	Futaba 4YF 4 Channel Basic	Full channel servo reversing for more installation options Transmitter and receiver NiCds can be recharged simultaneously with the included 50mA overnight charger. Power and servo reversing switches are located down and out of the way for convenience and to avoid accidental changes The battery meter features one green and one red LED for easy-to-read go/no go status.
	Airtronics VG400	Retractable antenna Mode 2 setup (available in mode 1 from Airtronics) Trim controls Servo Reversing on all channels Neck strap hook Trainer Button Carrying handle Throttle high and low point adjustment High power (500 mw) internal RF module Advance gimbal design w/ control stick length and tension adjustment LED voltage display Dual Conversion Transmitter and Receiver End Point Adjustment
	Hitec Laser	All channels have servo reversing and Adjustable Travel Volume (ATV) Adjustable length and tension gimbal sticks New Ergonomic Case. Trainer system adaptable (when you buy a trainer cord) SUPREME Hi-Tec 8 Channel narrow band, dual conversion receiver (0.8" height, 1.4" wide, 2.3" length, 1.34 ounces) Adjustable Travel Volume (ATV) on Channels 1 and 2. Elevon Mixing Option Channel 2 and 4 "V-Tail" mixing option. Telescoping antenna 5 LED Battery meter Rechargeable transmitter and receiver batteries 2 year warranty
	JR Quattro	# of Channels: 4 Ch Modulation: FM Band: 72 Servos: NES-527x4 Receiver: R600 Programming Features: Servo Reversing Modes: 2 Transmitter (Tx) Battery Type: 600 mAh 9.6 volt Charger: NEC-221 Switch: Standard Switch Output Strength: Approx 750 mw


	Moderatly Advanced Radios

NAME	SUPPLIER	DESCRIPTION
	Futaba 4YF 4 Channel Basic	This is the Futaba 6EXA 6 channel FM Computer Radio System with four S3004 standard size ball bearing servos. This system is designed for the first time modeler that prefers a computer style radio. *THIS RADIO CONTAINS NO HELI PROGRAMMING*
	Airtronics RD6000 Super	This is the Airtronics RD6000 Super 6 Channel Computer Radio for Planes/Helis. System Includes a 7-Channel PPM/FM Z-Connector Micro Receiver, and Four Standard Ball Bearing Z-Connector Servos.
	Hitec Optic	Airplane, sailplane and helicopter programming Shift select function and Spectra synthesized capability Eight model memory Digital trims Model name Dual timer Switch assignability Exponential Fail Safe Throttle lock EPA (End Point Adjustment) Engine cut Three flight modes Revo mixing Two open mixes Dual Rates CCPM mixing Gyro Gain Throttle curves Pitch curves CROW mixing Camber Reflex
	JR 6102	6 channels 10-model memory Airplane/heli programming 8-character model naming Selectable switch locations Trainer and pilot link systems Sub-trim adjustment Travel adjustment Servo reversing Dual rate/expo for aileron, elevon and rudder Direct Servo Control system (DSC) Digital trims Adjustable sticks Throttle cut system Failsafe system (for PCM only) Servo travel screen Model copy Flaperon, elevon and V-tail mixing (airplane) Flap system with elevator mix (airplane) Elevator-to-flap mixing (airplane) Aileron-to-rudder mixing (airplane) 4 programmable mixes (airplane) 5-point throttle and pitch curves (heli) Normal and stunt curves (heli) CCPM swashplate mix-90, 120, 180 (heli) Revo mixing (heli) 2 programmable mixes (heli)

Very Advanced Radios

There are some very advanced radios that have come out recently by Futaba, JR, Hitec, Airtronics, Multiplex and others. We have not included these as part of this documentation as they do not even come close to be considered beginner radios and should not be considered unless someone gives one to you. There is no reason to spend $350 plus on a radio when you do not even know how to fly. Most people now days buy a moderately priced computer radio and move up once they have flown for a while.