CONTINUED FROM THE PREVIOUS POST
Updated June 2015

CHANNELS AND CHANNELS

One of the things that confused me when I first started flying RC airplanes was this business of channels.

When using radios based on 27 MHz, 72 MHz and many other frequencies, channels can refer to the operating frequency of the radio. As stated above, it is critical to know the channel so that the transmitter and receiver can be placed on the same channel. Channel matching is usually done by inserting a crystal into the receiver so that the receiver matches the channel of the transmitter. This does not apply to Radio systems on 2.4 GHz.

Channels can also refer to the number of functions the radio system can control in the plane. We speak of three channel airplanes, four channel airplanes and more channel airplanes. Today you can buy radios that can provide 18 or more channels of control. What you would do with all those channels depends on the plane, but it is enough to say that for some applications, even 18 channels may not be enough.

In the United States, radio frequencies and their uses are regulated by the Federal Communications Commission, the FCC. The FCC has designated the 2.4 GHz and 72 MHz band as the primary recognized frequency range for model aviation. Please don't buy a radio on 75 MHz as that is designated for ground use such as cars and boats. The 2.4 GHz and 72 MHz standard is also recognized by Canada;s regulatory organization.

If you are considering buying a plane that uses a 27 MHz radio system you must be especially alert because 27 MHz is also used for low end cars and boats. That kid with the RC car could be on 27 MHz and on your channel. So keep an eye out for other RC uses and always speak to anyone using an RC device to be sure there will not be a conflict. 2.4 GHz does not have this problem.


CHANNELS OF CONTROL

The second use of the word channel in relation to radio systems has to do with how many channels of control they provide. A three-channel radio can control three devices on the plane. A six-channel radio can control six devices, and so on.

Some channels are proportional which means as you move the stick, dial or lever, the device is controlled in a proportional fashion. Move the stick left a little bit, the rudder moves left a little. If you move it a lot, the rudder moves a lot. That is proportional control.

Other controls have definite positions. For example the landing gear switch is either up or down. There is no half way. Some channels are controlled by switches, which might have three positions to designate three conditions such three different positions of the flaps.

If we look at the common starter electric planes most require only three proportional channels of control. You need pitch and roll in order to manage the plane in the air. Add to that a throttle channel.

In general, you can fly almost any model airplane with a four channel radio. That allows you to manage elevator, rudder, ailerons and throttle, for a powered airplane.

Radios with more than four channels provide greater flexibility. A six channel radio can add the control of landing gear and flaps. If you had more channels you could control smoke, lights, and other things on the airplane.

Let me leave the topic of channels on this note. You can buy radios with two channels and you can buy radios with twelve channels, and every step in between. What you buy will be determined by what you need, what you plan to do, and how much money you have to spend.

My usual advice is, if you start with an RTF airplane package then use the radio that came with that package and consider that radio dedicated to that package. When you are ready to take the next step THEN you are ready to look at making that larger investment in a "good radio". There is a chapter later in the book on selecting your first radio. I recommend you read it before making your first radio purchase.


PRICES AND PACKAGING

Before we can talk about prices of radios we need to be aware that radio systems are typically packaged in several ways. You can buy the radio alone, or you can get it with the receiver and it is very common to also include some number of servos. In some packages there may be a switch and a set of batteries and perhaps some servo extension wires. When you are looking at prices for radios be sure you know what is included.

Some package deals may be nicely priced for what you get, but may include components you canā€™t use. For example the package may include standard size servos and your plane may call for micro servos. If you really don't need those standard servos you can put them aside for use in a future plane, or you might be better off buying the radio alone and getting the rest separately. However, if the components are right, it is more convenient and often more cost effective to by it all as a package.


WHICH BRAND IS BEST FOR YOU?

There are many brands of radios. The big names in our hobby are Hitec, Futaba, Airtronics, JR and Spektrum. However there are many other brands of radios and many of the smaller brands are very good. There are also private labeled radios that are actually made by these major manufacturers under private label agreements. If you stay with these top five you can be pretty confident of getting good quality products with good service to back them. However if another brand is popular at your club and the clubs experience is good, don't be afraid to stray from the big five. The experience of your fellow flyers is a valuable guide.

In fact, many people will tell you that the best brand and model for you is the one or two that are most common in your club. If you get one of these there will be many people who can help you with their use. The assistance of a fellow flyer at the field can be extremely valuable so don't overlook this factor. There can be safety in numbers and convenience in using the same type of radio that everyone else is using.


STANDARD VS COMPUER RADIOS

In the olden days of as little as 20 years ago, there were standard radios and computer radios and the cost differences were huge. Standard radios had 2-6 channels of control, trim slides and perhaps not much more. If you needed to reverse a servo you remounted it or used a servo reversing adapter. If you needed special mixes for V tail planes you had to buy devices to put in the plane to create the mix.

Features like servo reversing and end point adjustment were later added to these standard radios. They did a good job, but were set-up to fly one plane. It ws common for pilots to have one radio for each plane so they could set it to the specifics of that plane and leave it that way. You could reset for each plane but this was troublesome and error prone.

Along came computer radios and the ability to store multiple model's settings in the radio. Now one radio could be used to fly many planes. In addition the radio could do channel mixing inside and transmit it to the receiver directly. You could mix channels together to manage V tail planes or elevons for flying wings. You could also control how far the servos would turn which is a great way to get the right amount of throw in your control surfaces. This was heaven, but it was expensive.

However if you buy a new radio today many of the least expensive radios will allow you to reverse a servo from the radio and include V tail and elevon mixing, and some even include end point adjustments to help you set the movement of your control surfaces. These were features that were common to the high end computer radios. Now they are appearing in the basic radios so every year you get more for your money.

However only the computer radios can store the settings for multiple airplanes. For many this is their most important feature.


Summary

So, that wraps up our discussion of radio basics. While we covered a lot, there is a lot more we could have discussed, but my fingers grow tired from typing and you need to take a break from reading. Ask your questions, make your statements and share you knowledge. It will make this all the more fun for all of us.