Receiver Power System Requirements
Inadequate power systems that are unable to provide the necessary minimum voltage to the receiver
during flight have become the number one cause of in-flight failures. Some of the power system
components that affect the ability to properly deliver adequate power include:
•Receiverbatterypack(numberofcells,capacity,celltype,stateofcharge)
•TheESC’scapabilitytodelivercurrenttothereceiverinelectricaircraft
•Theswitchharness,batteryleads,servoleads,regulatorsetc.
The AR500 has a minimum operational voltage of 3.5 volts; it is highly recommended the power
system be tested per the guidelines below.
Recommended Power System Test Guidelines
If a questionable power system is being used (e.g. small or old battery, ESC that may not have a BEC
that will support high current draw, etc.), it is recommended that a voltmeter be used to perform the
following tests.
Note:
The Hangar 9 Digital Servo & Rx Current Meter (HAN172) or the Spektrum Flight Log
(SPM9540) are the perfect tools to perform the test below.
Plug the voltmeter into an open channel port in the receiver and with the system on, load the control
surfaces (apply pressure with your hand) while monitoring the voltage at the receiver. The voltage
should remain above 4.8 volts even when all servos are heavily loaded.
Note:
The latest generations of Nickel-Metal Hydride batteries incorporate a new chemistry
mandated to be more environmentally friendly. These batteries when charged with peak detection
fast chargers have tendencies to false peak (not fully charge) repeatedly. These include all brands
of NiMH batteries. If using NiMH packs, be especially cautious when charging, making absolutely
sure that the battery is fully charged. It is recommended to use a charger that can display total charge
capacity. Note the number of mAh put into a discharged pack to verify it has been charged to full
capacity.
QuickConnect
™
With Brownout Detection
Your AR500 features QuickConnect with Brownout Detection.
•Shouldaninterruptionofpoweroccur(brownout),thesystemwillreconnectimmediatelywhen
power is restored (QuickConnect).
•TheLEDonthereceiverwillflashslowlyindicatingapowerinterruption(brownout)hasoccurred.
•Brownoutscanbecausedbyaninadequatepowersupply(weakbatteryorregulator),aloose
connector, a bad switch, an inadequate BEC when using an Electronic speed controller, etc.
•Brownoutsoccurwhenthereceivervoltagedropsbelow3.5voltsthusinterruptingcontrolasthe
servos and receiver require a minimum of 3.5 volts to operate.
How QuickConnect With Brownout Detection Works
•Whenthereceivervoltagedropsbelow3.5voltsthesystemdropsout(ceasestooperate).
•Whenpowerisrestoredthereceiverimmediatelyattemptstoreconnecttothelasttwofrequencies
that it was connected to.
•Ifthetwofrequenciesarepresent(thetransmitterwaslefton)thesystemreconnectstypicallywithin
one second.
QuickConnect with Brownout Detection is designed to allow you to fly safely through most short
duration power interruptions, however, the root cause of these interruptions must be corrected before
the next flight to prevent a crash.
Note:
If a brownout occurs in flight it is vital that the cause of the brownout be determined and
corrected.
Antenna Polarization
For optimum RF link performance it’s important that the antennas be mounted in an orientation that
allows for the best possible signal reception when the aircraft is in all possible attitudes and positions.
This is known as antenna polarization. The antennas should be oriented perpendicular to each other;
typically one vertical and one horizontal (see Receiver Installation). The long antenna can be mounted
in a position perpendicular at least 2 inches away from the short antenna using tape.
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Tips on Using Spektrum 2.4GHz
ModelMatch
™
Some Spektrum and JR transmitters offer a patent-pending feature called ModelMatch. ModelMatch
prevents the possibility of operating a model using the wrong model memory, potentially preventing
a crash. With ModelMatch each model memory has its own unique code (GUID) and during the
binding process the code is programmed into the receiver. Later, when the system is turned on, the
receiver will only connect to the transmitter if the corresponding model memory is programmed on
screen.
Note
: If at any time you turn on the system and it fails to connect, check to be sure the correct
model memory is selected in the transmitter. Please note that the DX5e and Aircraft Modules do
not have ModelMatch.
While your DSM 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:
If the receiver is turned off first
—all servos except for the throttle will be driven to their preset
failsafe positions set during binding. At this time the throttle channel doesn’t output a pulse
position 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 then turned on for a short period (the time it takes to
connect) all servos except for the throttle are driven to their preset failsafe positions while the
throttle has no output pulse. 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?
A: In order for the system to connect (after the receiver is bound) the receiver must receive a large
number of consecutive 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 ft.) or if the transmitter
is located near metal objects (metal TX 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 again will cause a connection to occur. This only happens during the initial
connection. Once connected the system is locked in and should a loss of signal occur (failsafe)
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 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 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 startup process of scanning the band
and finding the transmitter) and this can take several seconds. Please read the receiver power
requirement section 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 transmitter is placed
into bind mode, 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 DX7
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 DX7 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.”
FCC Information
This device complies with part 15 of the FCC rules. Operation is subject to the following two
conditions: (1) This device may not cause harmful interference, and (2) this device must accept any
interference received, including interference that may cause undesired operation.
Caution:
Changes or modifications not expressly approved by the party responsible for
compliance could void the user’s authority to operate the equipment.
This product contains a radio transmitter with wireless technology which has been tested and found
to be compliant with the applicable regulations governing a radio transmitter in the 2.400GHz to
2.4835GHz frequency range.
The associated regulatory agencies of the following countries recognize the noted certifications for
this product as authorized for sale and use:
Declaration of Conformity
(in accordance with ISO/IEC 17050-1)
No. HH20080903
Product(s):
AR500 Receiver
Item Number(s):
SPMAR500
The object of declaration described above is in conformity with the requirements of the specifica-
tions listed below, following the provisions of the European R&TTE directive 1999/5/EC:
EN 301 489-1, 301 489-17 General EMC requirements for Radio equipment
Signed for and on behalf of:
Horizon Hobby, Inc.
Champaign, IL USA
Sept. 03, 2008
Steven A. Hall
Vice President
International Operations and Risk Management
Horizon Hobby, Inc.