Spring 2006 Issue

Airborne Radio

Radio Systems

 By Del Schier, K1UHF

 

Futaba 6-meter receivers come in various sizes and levels of performance.

 

 

The RC equivalent

of an IC-7800 or

FT-dx9000.

This time I will cover RC (radio control) radios, the transmitters and receivers. There is no such thing as an RC transceiver . . . well, not quite. There are transceivers. More on their unique features will be found below. Normally, the transmitter, the part with the controls, is in your hands, while the receiver is in the airplane. The receiver controls the servos, which in turn control the airplane. The servos, in turn, are linked back to your fingertips with proportional control.

Many years ago I remember seeing old-time RC equipment at the ARRL museum. I don’t think it is on exhibit any more. However, I couldn’t get over how big and heavy everything was. The transmitter was a big wooden box, with a stick and a couple of switches, along with legs to support the transmitter on the ground. The airborne equipment, even with the relative lightness of subminiature tubes, was nevertheless weighted down by filament and plate batteries, requiring a big airplane to carry everything aloft. My first radios, made by FutabaTM and KraftTM, were in aluminum boxes that looked like standard BudTM mini boxes. Now they look like something from Star Wars.

Today’s RC radios are as modern as any other type of electronics, with digital technology adding endless features. Choosing your first RC radio equipment can be confusing, so here are the basics.

The Basics

RC transmitters and receivers are primarily classified by the number of channels they have, but there is much more. When I speak of channels, I refer to the number of control channels that the radio controls, rather than the frequency channel. To begin, you probably will need only three channels—one each for throttle, elevator, and rudder. It is hard to find a three-channel system. Even so, you should start out with more so that you can graduate to more sophisticated airplanes. To fly on the 6-meter ham band, you have no choice because the commercially available 6-meter radios all have seven or eight channels.

Manufactures that supply 6-meter transmitters and receivers include Futaba, JR, and AirtronicsTM. They only offer 6 meters in transmitters that have a plug-in transmitter module, a small RF deck that plugs into the back of the transmitter. These transmitters are their better versions, but they are relatively inexpensive. I purchased a used JR X347 module radio in perfect condition for $75 at the local hobby shop. My best new radio, a JR 8103, was $300. Both radios have about all the features an advanced modeler would need.

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