JR X9303 2.4

RADIOREVIEW
BY GERRY YARRISH PHOTOS BY HOPE McCALL
JR X9303 2.4
9-channels, 30-model memory, 3 model types with 2.4GHz frequency freedom
TTHE JR XP9303 radio system has been
around for about 21 ⁄2 years, and it has become
one of the radios I use most for reviewing
models for Model Airplane News. If there’s anything
I’d like to change about the XP9303 (see
the January 2005 issue), it would be to convert
it to a 2.4GHz version. Well, JR has done just
that with the introduction of the new X9303
2.4GHz system.
The Spektrum DX6 system (see March
2006 Backyard Flyer magazine) with its spread
spectrum technology was the first to arrive at
the 2.4GHz party, and it was followed by the
DX7 full-function 2.4GHz system. It was a relatively
easy brain transplant to integrate
Spektrum’s digital spectrum modulation
(DSM) and DuaLink receiver technology into
the new JR X9303 2.4 system. The X9303 2.4
is not just a modified transmitter with the
2.4GHz module plugged into its back; the
radio is a completely integrated system with a
shorter pivoting 2.4GHz antenna installed.
The R921 receiver is light
and very similar to the
Spektrum DX7 receiver.
Here the binding plug
needed to match new
receivers to your transmitter
is also shown.
92 MODELAIRPLANENEWS.COM
Laid out exactly like the popular XP9303, the new
2.4GHz X9303, has all its switches in easy reach.
This means that the X9303 2.4 is completely
compatible with all existing DX6 and DX7
Spektrum receivers, and it can easily be linked
to them.
TRANSMITTER
The 9-channel X9303 2.4 features a 30-model
memory and comes with three basic model
software menus for powered aircraft (ACRO),
sailplanes (GLID) and helicopters (HELI). The
Dual rates, auxiliary channel trims and mix switches
are clustered at the radio’s upper corners.
transmitter is the same as the XP9303’s; at the
upper left corner are the gear switch and
trainer button, the elevator dual rate switch,
the flap system switch and flap trim. At the
upper right corner are the auxiliary channel
trim—the auxiliary 2 switch, the aileron dual
rate switch, the mix switch and the auxiliary
4/rudder dual rate switch. There are two additional
auxiliary slide switches: one on top of
each side of the transmitter.
At the bottom of the transmitter, from left
to right are the enter, list and clear buttons,
the main display screen and the easy-to-use
rolling selector switch. Digital trims are used
for rudder, elevator and aileron trims, and the
throttle uses a standard mechanical ratchet
trim lever. The X9303 2.4 transmitter is available
with a 9-channel R921 receiver only, and
as a complete system, including a receiver battery
pack, switch harness, wall charger and
four DS821 digital servos.
FEATURES
Our test radio was configured for “Powered
Aircraft” (ACRO) use, and its features include:
• Flaperon/delta-wing types
• V-tail mixing
• Dual throttles (with independent curve and
trim for each)
• Elevator-to-flap mixing
• Aileron-to-rudder mixing
• Throttle curves (2)

TRANSMITTER
MANUFACTURER JR
DISTRIBUTOR Horizon Hobby Distributors
MODEL X9303 2.4
TYPE Aircraft
ENCODER 9-channel computer system
RF MODULE Fully integrated 2.4GHz
FREQUENCY BAND 2.400 to 2.483GHz
MODULATION Digital Spectrum Modulation
(DSM) with Direct Sequence Spread
Spectrum
SERVO-CHANNEL RESOLUTION 1024 w/4X
over-sampling
SPECTRAL CAPACITY 40 systems
POWER SOURCE 1500mAh 9.6V NiMH
RECEIVER
MODEL JR921 2.4
TYPE DSM2 DuaLink
NO. OF CHANNELS 9
FREQUENCY 2.4GHz
RECEIVER VOLTAGE RANGE
3.5 to 9V DC
WEIGHT 0.53 oz. (15g)
SYSTEM PRICE $730
(w/4 high-torque digital
821 servos)
JR X9303 2.4
THE X9303 2.4
HAS THE SAME
GREAT FEATURES
AS THE 9-CHANNEL,
30-MODEL MEMORY,
3-MODEL XP3903
RADIO SYSTEM
AUGUST 2007 93

RADIOREVIEW JR X9303 2.4
The main screen on the X9303 2.4 is very easy to read. Navigation and adjustment of the radio’s various
menus is made easy with the unique roller selector switch to the right of the screen.
• Flap system (3-position with elevator compensation
and delay)
• Snap-roll system (with 4 directions
and rates)
• Gyro system (3 gains for up to 2 gyros)
• Servo-speed adjustment (in both directions)
• Programmable mixers (6 total; 2 with
multipoint adjustment)
• Direct servo control (DSC)
MAIN DISPLAY
There’s very little confusion while navigating
the transmitter’s many program menus. The
main display shows the current model type
(with a graphic symbol) the trim positions,
the battery voltage, the model number and
the model’s name if you input that information.
The function screen is where you find
menus for dual rates/expo, servo-reversing,
subtrim, servo-travel adjustment, elevator-toflap
and aileron-to-rudder mixing, throttle
curves, flap system, servo speed, snap roll,
servo-speed adjustment and programmable
mixers 1 through 6. You also find the trainer,
timer and servo monitor menus.
In the system menus (press the enter button
and turn on the radio), you find the model
select, model name, type select, model memory
reset, data transfer, trim step function, device
(switch) selection and wing-type menus.
The navigation and adjustment of these program
functions is well detailed in my XP9303
review, and the process is easy and intuitive.
MODELMATCH
This feature puts an end to the “wrong model
94 MODELAIRPLANENEWS.COM
syndrome” if you neglect to double-check that
you have the correct model name on the transmitter
display before you fly your model. A
unique code embedded in the signal, will prevent
the receiver from responding if the wrong
model’s name is on the transmitter’s screen.
SERVOSYNC
This new feature actually re-sequences data
the transmitter transmits based on the type of
mixing you select. So, if you use dual elevators
on a giant model or a 3-servo CCPM setup for
X9303 2.4 FEATURES
The X9303 2.4 has aircraft, sailplane
and helicopter software menus.
Here are the basic aircraft program
features:
■ Switch assignment
■ Flight modes (3 aircraft, 5 sailplane, 6
helicopter)
■ Dual rates for aileron, rudder and
elevator (3 with flight modes)
■ Adjustable flight trims
■ Fail-safe (with hold and predetermined
servo positioning)
■ Trainer system (selectable channels)
■ Timers (stopwatch, countdown and
integrated)
■ Servo monitor
■ ModelMatch
■ ServoSync
■ Model memory transfer system
■ Model copy system
your helicopter, ServoSync ensures that the
servos that work together will receive their
impulses together. This allows the servo
movements to be more synchronized for
improved response.
RECEIVER
The JR R921 2.4 is a full-range receiver featuring
DuaLink technology and is actually two
receivers that each has its own set of antennas.
When powered up, the receiver scans the
2.4GHz band to find the transmitter it has been
programmed to recognize, and it locks on to its
signal. The second receiver circuit then repeats
the process and locks on to a second signal to
establish a dual-signal link to the transmitter.
The two antennas virtually eliminate
blocked-signal interference from nearby metal
objects such as big glow- and gas-powered
models and large battery packs. As with all
2.4GHz radio systems, the transmitter signal
beam is line-of-sight, so always avoid flying
behind large buildings or objects that could
block the signal.
Binding. Binding programs the receiver to recognize
your transmitter, and it’s done at the
factory. Binding or rebinding is necessary if
you purchase another receiver to use with
your transmitter and if you want to change
the built-in throttle-smart fail-safe settings.
Smart fail-safe. This built-in feature is set so that
if there is a signal loss, the throttle will go to a
low setting, and the other control channels will
remain in their last positions. If you turn on the
receiver before the transmitter, all the channels
go to their fail-safe positions (set during the
binding process), but as a safety feature, the
throttle channel does not produce a signal
pulse, so it can’t activate an electric model’s
ESC. The instruction manual explains the
binding and fail-safe setting processes in detail.
BOTTOM LINE
The JR X9303 2.4 is a user-friendly radio system
that’s ideally suited to intermediate to
expert fliers. I especially like the fact that with
its transfer system, you can easily bring all
your XP9303 model memories into the X9303
2.4. This is a real time saver. Add the
frequency freedom of DSM 2.4GHz frequency
modulation and the ability to link to all older
Spektrum receivers, and you have a radio
system that’s ideal types of RC flying.
See the Source Guide for manufacturers’ contact information.