Receiver Installation And Power System Requirements; Receiver Installation; Power System Requirements; Recommended Power System Guidelines - Spektrum DX18t Manuel D'utilisation

RECEIvER INSTAllATION AND POWER SYSTEM REQUIREMENTS

Receiver Installation

For optimum RF link performance, mount the main receiver and
remote antennas in an orientation that allows for the best possible
signal reception when the aircraft is in all possible attitudes and
positions. Where supplied with the transmitter, install the primary
receiver in your model. Put the primary receiver in protective foam
and install the receiver in the model using rubber bands or hook-
and-loop straps. Use thick double-sided foam tape to install the
primary receiver in electric airplanes or helicopters.
Mount each remote receiver at least 2 inches (51mm) away
from the primary receiver, primary antenna and each other using
double-sided foam tape. Orient the antennas perpendicular to each
other; typically one vertical and one horizontal (see manufacturer's
receiver installation instructions). This gives tremendous improve-
ments in path diversity as each receiver can "see" a different RF
environment. This is key to maintaining a solid RF link, especially
in aircraft that have substantial conductive materials (e.g., larger
gas engines, carbon fiber, pipes, etc.), which can weaken or block
the signal.
In airplanes, we recommend mounting the primary receiver in the
center of the fuselage on the servo tray and the remote receivers
on the side of the fuselage or in the turtle deck (space behind the
canopy and in front of the vertical stabilizer).
In helicopters, install receivers in the radio tray, where there is
usually sufficient room for receiver separation. Where there is not
sufficient room, install a receiver on an external receiver mount
made of clear plastic.
NOTICE: The DSMX DX18t is compatible with all current
Spektrum DSM2 and DSMX aircraft receivers, but NOT
compatible with the original DSM AR6000 receiver.

Power System Requirements

Set up and operate a model so power to the receiver is NEVER
interrupted while flying. This is especially critical on giant-scale
models that use several high-torque or high-current servos. Power
systems unable to provide minimum receiver voltage in flight are
the number-one cause of in-flight failures. Some components that
cause a receiver to have too little power supply include:
• Receiver battery
(number of cells, capacity, cell type, state of charge)
• Switch harness
• Battery leads
• Regulator (where used)
• Power bus (where used)
A Spektrum receiver's minimum operational voltage is 3.5 volts.
This battery charge capacity compensates for discharge during
flight or for flight loads larger than ground test loads.
CAUTION: We recommend that you DO NOT
fly a model with battery charges at less than 5.3-volts.
SPEKTRUM DX18t • TRANSMITTER INSTRUCTION MANUAL

Recommended Power System Guidelines

1. When setting up large or complex aircraft with multiple high-
torque servos, use a current and voltmeter (HAN172). Plug the
voltmeter in an open channel port in the receiver, and with the
system on, load the control surfaces on your aircraft by apply-
ing pressure with your hand. Monitor the current as you load
control surfaces. The voltage should remain above 4.8 volts
even when all servos are heavily loaded.
2. With the current meter inline with the receiver battery lead,
load control surfaces while monitoring the current. The maxi-
mum continuous recommended current for a single heavy-duty
servo/battery lead is 3 amps. Short-duration current spikes of
up to 5 amps are acceptable. If your system draws more than
these currents, you need to use multiple packs of the same
capacity with multiple switches and multiple leads plugged into
the receiver.
3. If using a regulator, perform tests for a 5-minute period. A
regulator may provide adequate short-term power, but this
tests its ability to maintain voltage at significant power levels
over time.
4. For really large aircraft or complex models, multiple battery
packs with multiple switch harnesses are necessary. No matter
what power systems you choose, always carry out test #1.
Make sure the receiver is constantly provided with 4.8
volts or more under all conditions.
CAUTION: When charging any brand of Ni-MH
battery pack, make sure the battery is fully charged. Due to
the nature of peak charges and variations in charging rates,
heat development, and cell types–the capacity reading of a
battery charged on a fast peak charger may only reach 80%
of its nominal value. Use a charger that displays total charge
capacity. Note the number of mAh put into a discharged
pack to verify the charge is at full capacity.
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