Spektrum DX6i - Manual (Page 22)

22 SPEKTRUM DX6i • RADIO PROGRAMMING GUIDE
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.