Q-48: In the June issue of Model Aviation in your article titled “Introduction to Parking Lot Flying” is a photo of you and your grandson (page 49, right side). In that photo you are holding a 'pro-type' or advanced RC transmitter. Don’t you realize that you shouldn’t be using or even suggesting the use of a 'high-powered' RC transmitter for parking lot flying? Your advanced RC transmitter might easily interfere with other parking lot flyers operating several blocks away. I can’t believe you did this!
A-48: I had to sit back and think about this for a few seconds. My
reader friend was sincere and concerned. The transmitter I happened to be using
when that photo was taken was a Hitec Eclipse. It is one of my most popular
transmitters, and I generally use all seven memory positions while operating my
“fleet” of parking lot and indoor RC models. It is definitely an “advanced” RC
transmitter.
But you must understand that it is advanced by virtue of having an internal
microchip, or essentially a computer circuit. This chip provides many extra
control features and allows for the storage of specific controls in a memory
bank that can handle as many as seven models. Keep in mind that the computer
circuits are what make this an advanced RC transmitter.
Consider also that on the output side of this transmitter, the radiated
radio-frequency (RF) power going to the transmitter’s antenna is limited by FCC
regulation to 3/4-watt (750-milliwatt) output. All RC transmitters conform to
this specification.
In fact, it is more than likely that most of the output circuit semiconductors
are the same type or close to it. Considering this, all RC transmitters, from an
output standpoint, are essentially created equal.
Yes, it is possible that two groups of parking lot flyers, several blocks apart,
might interfere with one another. But if such interference occurred, it would
simply be because of the closeness of the groups--not because of the
transmitter's power output.
I got back to the reader and explained everything. He believed my explanation
and was actually slightly embarrassed that he even brought up the subject. The
fact is that local parking lot flyers should be aware of who is flying in the
immediate area. Local hobby shops and RC clubs can help pinpoint parking
lot-flying activity so that one person doesn’t interfere with another. The
problem will always be there; it’s just that the transmitter's output power is
not the real problem.
An excellent way to avoid RC interference from groups flying in close proximity
is by using an RC transmitter that has a built-in scanning receiver. Polk’s
Hobby's Tracker II and several of the new Hitec/Multiplex transmitters have this
feature.
When you turn your transmitter power switch on, only the scanning receiver is
turned on. In a few seconds this receiver scans the channel on which you are set
to operate. If it is clear, the receiver will indicate “OK” and turn on the
signal. If it senses someone else on the same channel, it states “Wait—In Use”
and will not allow you to operate your RC system.
This takes the guesswork out of frequency control. It is also perfect for
determining if another parking lot flyer is attempting to fly nearby on your RC
channel.