LENSn earlier decades, remote-control
systems for model cars and aircraft
were simple affairs. All transmitters and
receivers were compatible with each other,
so long as they shared the same frequency,
and they would have been paired with each
other by having matching plug-in quartz
crystals. Their modern descendants have a hugely
expanded feature set, but at the cost of greater
complexity and a few pitfalls for the unwary buyer.
All the transmitters and receivers you are likely
to encounter will use the same frequency band,
2.4GHz. There are no channels as there were in the
old days; they share the same frequency and operate
by pairing the code on the receiver with that on thetransmitter, by pressing
a button on the receiver
at power-on and starting
the transmitter in a
special pairing mode.
All transmitters are
no longer compatible
with each other, there
are a variety of competing protocols on the market,
and it is easy to make the mistake of buying the
wrong ones and ending up with a mismatch. We
STRONGLY suggest buying your transmitter and
receiver together as a package, to make sure that
you know they will work with each other, or at
least buying them from the same manufacturer and
ensuring that they both speak the same protocol.
We bought a relatively inexpensive transmitter, a
FlySky, for our build because this article is intended
to be as accessible as possible, but you will find
transmitters and receivers with prices rising up into
the stratosphere.
The receiver will be a small board or module that
will connect to the flight controller with a single
serial cable. There are several protocols for this
communication, for example SBUS, IBUS, or PCM.
SBUS seems to be the favoured one, but in our case
we must admit that we had significant problems
getting our receiver and controller to speak to each
other using it, and had to fall back to the somewhat
inferior PCM.
The receiver should be able to draw its power
from the BEC circuit on the flight controller, but the
transmitter will require its own batteries. Frequently
these are just domestic AA cells, or sometimes an
internal Li-poly pack.I
COMMANDING
YOUR CRAFT
Choosing a
radio
FURTHER READING
We’re only just scratching the surface of multirotor
building here, and there’s a fantastic range of information
available online.
Whether you’re looking for a bigger, faster, or lighter drone,
you should find what you need to extend your skills. These are
some of our favourite resources:- Oscar Liang (https://oscarliang.com)
- GetFPV (https://www.getfpv.com/learn)
- RCGroups (https://www.rcgroups.com)
Above
Our FlySky FS-i6
transmitter, a budget
model that shouldn’t
break the bank