Copyright © 2009-2012 Eagle Tree Systems, LLC
http://www.eagletreesystems.com
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Audio/Variometer Configuration Menu
The Audio/Variometer Configuration menu has the following items:
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Mute Voice Alerts: Turns off all voice alerts, when set to YES.
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Set Voice Alerts Volume: Sets the volume of the voice alerts. Note that the purpose of the volume control is to match the volume of the voice
alerts with the volume of the flying sounds (if you use a microphone), and with the volume of the acoustic variometer. In general, this setting
should be set as low as possible to avoid saturating the output preamplifier (usually not above 1 or 2).
•
Mute Variometer: Mutes the acoustic variometer sounds, when set to YES.
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Set Variometer Volume: Sets the volume of the acoustic variometer. Note that the purpose of the volume control is to match the volume of the
variometer with the volume of the flying sounds (if you use a microphone), and the voice alerts. In general, this setting should be set as low as
possible to avoid saturating the output preamplifier (usually not above 1 or 2)
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Mute External Audio: Mutes the microphone, when set to YES. Note: this should be set to YES if you are not using a microphone. Otherwise a
hum may be heard.
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Set External Audio Volume: Sets the volume of the external microphone input. Note that the purpose of the volume control is to match the
volume of the microphone with the volume of the acoustic variometer, and with the volume of the voice alerts. In general, this setting should be
set as low as possible to avoid saturating the output preamplifier (usually not above 1 or 2)
Additionally, your OSD Pro contains a sophisticated varying tone variometer, employing electronic Total Energy Compensation. Basic variometers do
not support total energy, which means that “stick thermals” are reported by the variometer if you descend or ascend due to elevator movement.
Standard total energy variometers reduce the effects of moving the elevator by monitoring the pitch of the aircraft, which requires an additional probe to
be mounted. The OSD Pro system uses changes in speed to calculate total energy, requiring no additional pitch probe.
The variometer produces a varying tone, which changes as you ascend or descend at different rates. When ascending, the tone will be broken, with the
tone frequency increasing as the rate of ascent increases. When descending, the tone will be continuous, with the tone frequency decreasing as your rate
of descent increases.
The variometer uses either GPS altitude or an optional barometric altimeter. It uses either the airspeed pitot tube or the GPS speed for total energy
calculations. The types of sensors used are selected in the “Configure Sensors and Units” menu.
The sensitivity of the variometer is directly dependent on the sensitivity of the altimeter. In general, if you want to use the variometer for “thermal
sniffing” with a glider, we recommend using the OSD Pro with our high resolution Altimeter V4.
Several parameters of the variometer are adjustable, in this menu:
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Set Vario Averager Seconds: This setting controls the averaging period of the variometer, in 10ths of a second units. For faster response, lower
periods are recommended, but in rougher air longer periods may be required to avoid false alarms.
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Set Vario Minimum Sinkrate: this setting controls the minimum sinkrate. Normally, this would be set to the standard sinkrate of your vehicle,
i.e., the rate at which it descends in smooth air with no thermals. When you descend at a rate greater than this sinkrate, the variometer will start to
sound
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Set Vario Minimum Climbrate: this setting controls the minimum climbrate. When you ascend at a rate greater than this climbrate, the
variometer will start to sound,
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Set Vario Audible Tone Gain: This setting changes the amount the pitch changes as the climbrate increases/decreases. If you are not hearing
enough change, increase this parameter, and vice versa for too much frequency change.
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Set Total Energy Comp Percnt: this adjusts the scaling of the Total Energy Compensation calculation. 100% means that Kinetic Energy is
converted into Potential Energy directly, i.e., any change in airspeed is assumed to directly negate any change in altitude. Less than 100% reduces
the degree which airspeed change affects Total Energy, and increasing it above 100% increases the amount.
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Vario Off when Motor Running: This option disables the variometer tones when the motor is running, based on the amperage draw of the motor.
This is useful for “motor gliders.” The variometer is off when motor current is more than approximately 1.5 amps.
