Spektrum SPM9540 - Manual (Page 3)

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SPM9540 Flight Log User Guide
The Flight Log is an optional component that was originally designed for testing,
but now it is offered as a handy device that gives you a clear digital readout of
your radio performance. The Flight Log is not required, but for complex aircraft it
provides an intuitive analysis of the overall performance of the radio installation.
Some of today’s models can be very demanding. The Flight Log ensures that your
system is working properly and you have optimized the radio installation.
The Flight Log provides the following information:
• System Voltage—Receiver Pack Voltage
• Antenna Fades
• Frame Losses • Holds
Guidelines for DSM2
• An antenna fade represents a loss of a bit of information on that specific antenna.
Typically, it’s normal to have as many as 50 to 100 antenna fades during a flight.
• A frame loss represents simultaneous antenna fades on all attached receivers.
If the RF link is performing optimally, frame losses per flight should be less
than 20.
• A hold occurs when 45 consecutive frame losses occur. This takes about one
second. If a hold occurs during flight, it’s important to re-evaluate the system,
move the antenna to a different location and/or check to make sure the
transmitter and receivesr are all working correctly.
Guidelines for DSMX
• Holds—Holds are unacceptable. If a hold occurs, please investigate and correct
the issue before next flight.
• Frames—<100- In conventional models during a 10 minute flight, frames
should typically be less than 100 on all receivers.
• Fades—Use Fades for comparison only. All attached receivers should have
similar Fades. If not, investigate poorly performing receivers (location, antenna
orientation, etc) and correct.
Operational Differences between DSM2 ™ and DSMX ® receivers while
using the Flight Log:
DSMX is frequency agile while DSM2 finds two quiet channels and remains
on those channels. Consequently, because DSMX operates on quiet and noisy
channels, it’s common to have more Antenna Fades and Frame Losses than when
using DSM2 in busy 2.4GHz environments.
Specifications
Dimensions: 1.06 x 0.71 x 0.45 in (27.0 x 18.0 x 11.5mm)
Weight: 0.24oz (6.69 g)
The Flight Log displays the following data:
• Displays antenna fades
• Displays frame losses
• Displays fail-safes
• Receiver battery performance