Why Do I need Radio Equipment?
 It
may sound like a stupid question to the obvious, but it really is a good question.
Simply put, kits on the market today do NOT include the radio
system. If you are looking for a complete system, then one of the Ready To Run
packages are for you. These include the boat, radio gear and other needed items to
get you in the water quickly. The important idea here is that the radio system is an
item by itself, even if it is bundled with other things in a package. So even if you get
the radio with your boat, you will still need a basic working knowledge to use it.
But, these packages are mostly devoted to the speed demons among us. So us
"scale buffs" need to know as much about radio gear to make the right selection
when buying one for our boats.
The radio system is basically
your link between your model and most of all, you. Radio systems may seem complicated at
first but with a little study, all of the aspects of the radio system can be easily
understood. I will attempt to introduce you to the basics of radio systems, how they
relate to boating and explain a few of the features found on many of the systems available
today.
So, are all radios the
same?
Radios are separated into two
groups, those used for model aircraft and those used for surface models. Although the
operation, electronics, and mechanics for both types of systems are virtually identical,
they operate on different sets of frequencies. The separation is stipulated by law
and it is to protect the safety of the modeler and those in the vicinity. A flying
aircraft can be dangerous if it becomes uncontrolled and the frequency separation helps
avoid an aircraft being interfered with by someone operating a car or boat.
In addition to a difference in
frequencies, some surface radios are also available with a pistol grip control which is
ergonomically easier when controlling cars and boats. A pistol grip for aircraft would be
impractical.
Types of Radio Modulation
For some modelers, this can be a confusing
subject. I will try to explain the difference between them here. When shopping for a radio, you will find
that people refer to a few different types of modulation. They are referring to the way
the electronic control information |
|
is sent from your transmitter to the receiver
in your model by means of radio waves.
AM — AM, or
Amplitude Modulation, was the primary means of modulation in R/C until recently. The
control information is transmitted by varying the amplitude of the signal.
FM — FM, or
Frequency Modulation, is now the common method and is less prone to interference than AM.
Information is transmitted by varying the frequency of the signal.
PCM — In PCM, or
Pulse Code Modulation, FM is still utilized, however the control information is in the
form of a digital word rather than just a pulse width as in standard AM or FM. Using PCM
adds additional protection against interference from various sources.
How Does It Work?
We now know that AM stands for amplitude
modulation. Let's say you and I went to a bar for "Happy Hour". When we
first get there I start shouting the word "Hello!" to you from across the bar.
If I shout it a little louder, you to turn to your left. And if I shout a little quieter,
you to turn to your right. If I shout faster, you turn more. If I shout slower, your turn
less.
Again, FM stands for frequency modulation. So
now imagine another person is shouting the word "left", "center", and
"right" at you from across the bar. You respond to the verbal commands
accordingly. Again, you turn more or less as his shouting becomes more or less frequent.
Under ideal conditions, both of these radio
systems will work equally well. In fact, under most conditions, these radio systems are
virtually indistinguishable from each other. But conditions are not going to be ideal all
the time.
Now that it is a little later, the bar is
starting to fill up with other people. The background noise may easily drown out the
difference in how loud I am shouting "Hello!" to you, but it takes a lot more
noise to drown out the difference between "left", "right" and
"center" that the other person is shouting to you. Herein lies the strength of
the FM radio system. Background noise only affects the amplitude of the signal that is
being transmitted. By depending on frequency change, instead of amplitude change, the FM
system is far better at rejecting background noise and interference. |
