G-26
3. Q: I’ve heard that the DSM system is less tolerant of
low voltage. Is that 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 most servos cease to operate at around
3.8 volts. When using multiple 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, 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. Please read the receiver power requirement
on page G-24 as this explains how to test for and
prevent this occurrence.
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 bind button on the transmitter is pressed 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 that
use 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 pushed the bind button before turning on the
transmitter, also causing the system to “lose its bind.”
If, when turning on, the system fails to connect, one of
the following has occurred:
• The wrong model has been selected in the model
memory (Model Match).
• 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 bind button was unknowingly (or knowingly)
depressed and the transmitter was turned on
previously, causing the transmitter to no longer
recognize the receiver.
5. Q: Can I use a 3-cell Li-Po pack in my transmitter
A: No. All current JR and Spektrum transmitters are
designed to operate using a 9.6-volt transmitter pack.
A fully charged 3-cell Li-Po pack puts out 12.6 volts.
This higher voltage can overload the power-regulating
transistor causing damage and or failure, possibly
in flight. Many of our customers have experienced
failures using 3-cell Li-Po packs and their use in JR
and Spektrum transmitters is highly advised against.
The X9303 2.4 system will operate for over 15 hours
using a 2700mAh Ni-MH battery.
6. Q: How important is it that I test my system using a
flight log?
A: For most sport airplanes and helicopters, the use
of the flight log is unnecessary. For sophisticated
aircraft, especially those that have significant
conductive materials within the airframe (i.e. jets,
scale airplanes, etc.), the Flight Log offers an extra
measure of confidence that all radio components are
working optimally. The Flight Log is an important
tool that allows the confirmation that the installation
(position of the internal and remote receivers relative
to the conductive materials in the aircraft) is optimized
and that the RF (radio) link is operating at the highest
levels of performance.
Tip on Using 2.4GHz Systems (continued)
