Tips On Using 2.4Ghz Systems - Spektrum DX6I User Manual

TIPS ON USING 2.4Ghz SySTEMS

Your DSM2 equipped 2.4GHz system is intuitive to operate, functioning nearly identically to 72MHz systems.
Following are a few common questions from customers:
1. Q: Which do I turn on first, the transmitter or the receiver?
A: It doesn't matter, if the receiver is turned on first-the throttle channel doesn't put out a pulse position
at this time, preventing the arming of electronic speed controllers, or in the case of an engine powered
aircraft, the throttle servo remains in its current position. When the transmitter is then turned on
the transmitter scans the 2.4GHz band and acquires two open channels. Then the receiver that was
previously bound to the transmitter scans the band and finds the GUID (Globally Unique Identifier code)
stored during binding. The system then connects and operates normally. If the transmitter is turned
on first, the transmitter scans the 2.4GHz band and acquires two open channels. When the receiver
is turned on, the receiver scans the 2.4GHz band looking for the previously stored GUID, and when it
locates the specific GUID code and confirms uncorrupted repeatable packet information, the system
connects and normal operation takes place. Typically this takes 2 to 6 seconds.
2. Q: Sometimes the system takes longer to connect and sometimes it doesn't connect at all. Why?
A In order for the system to connect (after the receiver is bound) the receiver must receive a large number
of continuous (one after the other) uninterrupted perfect packets from the transmitter in order to connect.
This process is purposely critical of the environment ensuring that it's safe to fly when the system does
connect. If the transmitter is too close to the receiver (less that 4 feet) or if the transmitter is located near
metal objects (metal transmitter case, the bed of a truck, the top of a metal work bench, etc.) connection
will take longer and in some cases connection will not occur as the system is receiving reflected 2.4GHz
energy from itself and is interpreting this as unfriendly noise. Moving the system away from metal
objects or moving the transmitter away from the receiver and powering the system up again will cause
a connection to occur. This only happens during the initial connection. Once connected the system
is locked, and should a loss of signal occur (fail-safe), the system connects immediately (4ms) when
signal is regained.
3. Q: I've heard that the DSM system is less tolerant of low voltage. Is this correct?
A: All DSM receivers have an operational voltage range of 3.5 to 9 volts. With most systems this is not a
problem as in fact most servos cease to operate at around 3.8 volts. When using multiply high current
draw servos with a single or inadequate battery/ power source, heavy momentary loads can cause the
voltage to dip below this 3.5 volt threshold thus causing the entire system (servos and receiver) to
brown out. When the voltage drops below the low voltage threshold (3.5 volts), the DSM receiver must
reboot (go through the start up process of scanning the band and finding the transmitter) and this can
take several seconds.
Note: Receivers manufactured after July of 2007 offer a quick connect feature that reconnect
immediately when recovering from a low voltage "brown out."
Please read the receiver power requirement on page 21 as this explains how to test for and prevent
this occurrence.
22 SPEKTRUM DX6i • RADIO PROGRAMMING GUIDE
4. Q: Sometimes my receiver loses its bind and won't connect, requiring rebinding. What happens if the
bind is lost in flight?
A: The receiver will never lose its bind unless it's instructed to. It's important to understand that during
the binding process the receiver not only learns the GUID (code) of the transmitter but the transmitter
learns and stores the type of receiver that it's bound to. If the trainer switch is pulled on the transmitter
at any time and the transmitter is turned on, the transmitter looks for the binding protocol signal from
a receiver. If no signal is present, the transmitter no longer has the correct information to connect to a
specific receiver and in essence the transmitter has been "unbound" from the receiver. We've had several
customers using transmitter stands or trays that unknowingly depress the bind button and the system is
then turned on, losing the necessary information to allow the connection to take place. We've also had
customers that didn't fully understand the range test process and pull the trainer switch before turning
on the transmitter, also causing the system to "lose its bind." If the system fails to connect, one of the
following has occurred:
• The wrong model has been selected in the model memory (ModelMatch).
• The transmitter is near conductive material (transmitter case, truck bed, etc.) and the reflected 2.4GHz
energy is preventing the system from connecting. (See #2 above)
• The trainer switch was pulled and the radio was turned on unknowingly (or knowingly) previously,
causing the transmitter to no longer recognize the receiver.
SPEKTRUM DX6i • RADIO PROGRAMMING GUIDE 23