SANDIA aerospace STX 165 Manual

STX 165STX 165
STX 165STX 165
STX 165
Mode A/C TransponderMode A/C Transponder
Mode A/C TransponderMode A/C Transponder
Mode A/C Transponder
Pilot’s GuidePilot’s Guide
Pilot’s GuidePilot’s Guide
Pilot’s Guide

Copyright 2011
SANDIA aerospace
All Rights Reserved
This document and the information contained herein is the proprietary data of SANDIA aerospace, Inc. No
port of this document may be transmitted, reproduced, or copied in any form or by any means without the prior
written consent of SANDIA aerospace, Inc. Due to SANDIA aerospace’s continued product and quality im-
provement programs, information contained in this document is subject to change without prior notice.
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STX 165 Panel Mounted Mode A/C Transponder
Caution: Prior to starting or turning off the aircraft engine,
the avioncs master should be turned off to prevent pos-
sible damage to your avionics.
Note: Mimimum dispay intensity is preset by the pilot in
the user configuration mode.
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The STX 165 and STX 165R (remote) are ModeA/CAir Traffic Control Beacon System (ATCRBS) transpon-
ders that receive ground radar interrogations on a frequency of 1030 MHz and transmit replys on a frequency
of 1090 MHz. The STX165 is capable of transmitting one of 4,096 pilot entered codes which differ in both the
position and number of pulses that are transmitted. These coded reply’s allow ATC to display your aircraft’s
position, selected identifier, groundspeed and altitude on their radar screens. This information aids controllers
in maintain aircraft separation and proper approach and departure sequencing.
The STX 165R is a remote unit that can be interfaced to and controlled by other manufactures navigations
systems. For operation of the STX165R refer to the manufactures Pilot Guide of the unit controlling the STX
165R This manual will only address the operation of the panel mounted STX 165.
The STX 165 is a panel mounted transponder and uses a bright OLED display that is viewable in virtually all
lighting conditions. The STX 165 detects ambient lighting conditions and automatically dims or brightens
depending on the conditions. The minimum display intensity can be set by the pilot in the user set up mode.
The controls have been arranged to simplify data entry and retrieval while conserving valuable aircraft panel
space.

STX 165 Features
In additon to displaying the transponder code, the STX 165 has the following features the provide the piolt
with vaulable information
Pressure Altitude. The STX 165 has a built-in encoder that is certified
to 35,000 feet. The Unit will disply the Pressure alti-
tude in the lower left hand quadrant
Note: Temperature scale and flight timer initiation altitudes are preset by
the pilot in the user configuration page.
Note: Pressure altitude is derived from the STX 165’s built-in encoder and
is not baro corrected. It is the sale altitue as that being transmitted toATC
OAT When Sandia’s optional ST 78 OATprobe is installed
the STX 165 will disply Outside Air Temeperature
(OAT) in either Foor Co.
Density Altitude When Sandia’s optional ST78 OAT probe is installed
the STX 165 will disply Density Altitue in feet.
Icing Alert When Sandia’s optional ST78 OAT probe is installed
the STX 165 will disply a Snow Flake in the upper
right corner of the display at a preset temperature to
indicate freezing and possible icing conditions.
Eplased Flight Timer An elpased flight timer is intitiated at system start up
or after take off at a predetermined pilot entered alti-
tude. Non resetable in flight
Count Up Timer A resetable count up timer is controlled by the pilot.
Count Down Timer A preset time is entered and started by the pilot.
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STX 165 Display and Controls
The STX 165 uses a bright sunlight readable OLED display that automatically dims to adjust to ambient
light conditions. The can be times however when some pilots may have a hard time reading the display,
especially in bubble canopies when the STX 165’s display is pointed directly at the sun. In this case, the
pilot can press and hold the VFR pushbutton for three seconds and the code will be displayed in large
numbers. In this condition, the Mode will continue to be displayed and both the mode and code can be
changed. To exit this mode press and hold the VFR pushbutton for three seconds again.
The STX 165 display can be thought of as being divided into four quadrants.
Upper Left Hand Quadrant is the Mode in which the STX 165 is operating.
SBY: or standby the display is on and the unit fully functional, except it is not replying to transponder
interrogations.
ON: The STX 165 is on and responding to interrogations but not send out the aircraft altitude infor-
mation also call Mode A
ALT: The STX 165 is on and responding to transponder interrogation with altitude data, also called
Mode C.
Reply Light This is a bar that will blink at a 1 Hz rate whenever the STX 165 is replying to transponder
interrogation It is directly under the Mode.
Upper Right Hand Quadrant: This displays the transponder code currently being transmitted by the STX 165
Lower Left Hand Quadrant: This show the pressure altitude (PALT) being sensed by the built-in encoder and
transmitted by the STX 165. If the Sandia ST 78 OAT probe is installed the quadrant will also display
Density Altitude (DALT) and Outside Air Temperature (OAT)
Lower Right Hand Quadrant: This area shows the three timer functions, Elapsed Flight Time (EFT), Timer
Up, and Timer Down (Timer DN).
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Caution: Pressing and holding theVFR pushbutton for less than three seconds will
cause the VFR code to be displayed and become the active code.

SELECT The SELECT knob is the large outer knob of the stacked pair on the lower
right of the STX 165. This is a momentary knob that can be turned clockwise
or counter clockwise and will move the ‘cursor’one postion. When released,
it will return to the nutral position. The SELECT knob is used to move the
cursor over the code digits so that a different code can be entered by the pilot.
DATA The DATA knob is the smaller, outer knob of the stacked pari in the lower
right hnad corner of the STX 165. It can be turned either clockwise or counter
clockwise to enter data.
ENTER The ENTER puchbutton is the smaller, outer knob in the lower right courner
of the STX 165. Pressing the ENTER pushbutton stores pilot entered data in
the STX 165. It is repersented by the international enter symbol
VFR The VFR pushbutton is used to toggle between the units programmed VFR
code and the last pilot entered code.
IDT The IDT pushbutton is pressed to squawk Ident when requested byATC.
When IDT is pressed the unit will stay in the IDENT mode for 22 seconds
and the IDENT annunciator will be illuminated.
POWER The STX 165 is designed to come on automatically when the avionics master
switches is turned on. The STX 165 can be turned OFF by pressing and holding
the power/mode pushbutton for three seconds. If the pushbutton is disengaged
prior to the three second time out, the unit will remain in the ON mode. The
STX 165 always comes on the last active code.
MODE Turing the MODE control selects one of three MODES of operation, Standby
(SBY) in which all functions are operational except that the unit is not transmit-
ting reply. ON, the STX 165 is replying to interrogations but not reporting alti-
tude (ModeA). ALT, the STX 1656 is replying to radar interrogation and report-
ing altitude (Mode C). The STX 165 always turns on in the Standby mode. The
STX 165’s Mode is shown in the upper left quadrant of the OLED display
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Note: Since the STX 165 uses pressure altitude to determine when to turn
on, it will automatically turn off. The pilot should ensure that the unit is
turned to the SBY Mode after landing.
A 1200 squak code is displayed in the upper right quadrant of the units display.
To change the squawk code, rotate the SELECT know once clockwise to place the cursor over the first
digit in the squawk code. Consecutive turns of the SELECT knob will move the cursor progressively
over each digit. Turning the SELECT knob counter clockwise will reverse the travel of the cursor.
Once the cursor is over the digit to be changed, rotate the DATAknob either direct to select the desired
number. Continue this until all the digits have been changed to the new squawk code. Then simply
press enter to activate the new code.
To squawk VFR, simply press the VFR pushbutton. The programmed VFR code will be displayed. If
you push the VFR pushbutton inadvertently and want to return to the previous code, simply press the
VFR code again.
Note: Pressing theVFR pushbutton cycles between theVFR code and the last pilot
programmed code.
Pressing and holding the VFR pushbutton for three seconds causes the display to
go to a large font on only the mode and squawk code are displayed. Pressing the
VFR pushbutton again for three second restores to display to normal.
When power is applied the STX 165 will tun on with the last active squawk code. The pilot can then
change it to the code requested by the controller. The active code is shown in the upper right quadrant
of the display.
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Mode Selection
The STX 165 automatically turns on in the SBY (standby) mode when external power is applied,
normally via the avionics master switch. The pilot can use the MODE control to select On (modeA)
orALT (Mode C) if desired. The STX 165 also has the ability to automatically selectALT mode once
the aircraft has taken off and reached at a predetermined altitudeAGL. Once this altitude is sensed by
thebuilt-inencoderthe STX 165willautomaticallyturn on to theALT mode. This altitude is preselected
by the pilot in the User Set up page.
STX 165 Operation

A flashing bar under the mode in the upper right hand corner of the display is the STX 165’s reply
annunciator. It will blink at a 1 Hz rate whenever the STX 165 is replying to interrogations ground or
TCAS interrogations.
Pressure Altitude, Density Altitude, Outside Air Temperature
The STX 165 will display PALT in the lower right quadrant of the display. This quadrant can also
display Density Altitude (DALT) and Outside Air Temperature (OAT) if the optional SANDIA aero-
space STP 78 OAT probe is installed. Upon initial turn on the PALT display will be blanked until the
transducer hearter has come up to temperature. Depending upon the ambient air temperature, this can
take up to a minimum one minute.
Note: If the optional STP 78 OAT probe is not installed only Pressure Altitude
(PALT) will be displayed in the lower right quadrant.
Timer Functions
The STX 165 has three timer functions that are displayed in the lower left display quadrant. To select
the desired timer, rotate the SELECT knob twice clockwise or once counterclockwise. The turn the
DATA knob to select the desired Timer function.
Elapsed Flight Time (EFT) begins counting when the unit is powered up or reaches a preset AGL
altitude that is programmed by the pilot in the user set up mode. The EFT is not resettable after power
up. The EFT counts in minutes and seconds up to 59 minutes and 59 seconds and then begins counting
in hours and minutes.
Note: The TIMER UP counts in Minutes and Seconds for 59 minutes and 59 sec-
onds and then displays time in hours and minutes.
Caution: If the computed altitude is out of range the PALT display will show -9982
feet. If there is an altitude failure the PALT display will show -9981. Note that
neither of these are valid altitudes in the normal mode.
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To display the alternate functions in the lower right quanrant, turn the SELECT knob once in the
closckwise direction. The displayed data in the lower right quadrant will blink.Turn the DATA knob
until the data you want displyed is visable. Then press the ENTER pushbutton. If the ENTER push-
button is not pressed within 15 seconds the display will revert to the previous information.

Timer Up is a resettable timer that allows the pilot to time various task, such as holding pattern legs.
To begin the Timer Up function, rotate the SELECT knob to the lower right quadrant, and then rotate
the DATA knob until the TIMER UP is shown. Press the ENTER pushbutton and the TIMER UP
begins to blink. Press the ENTER again and the timer begins to count up. To reset the TIMER UP,
press and hold the ENTER pushbutton for three seconds. TheTIMER UPwill reset to 00:00. Press the
ENTER pushbutton while the time is blinking and the timer up will begin counting. If the ENTER
pushbutton is not pressed within 15 seconds, the timer is stop blink and the counter will stay at 00:00.
In this case, to begin the counter, rotate the SELECT knob over the TIMER UP display and push the
ENTER pushbutton . The TIMER UP will begin counting up. The TIMER UP counts in minutes and
seconds up to 59 minutes and 59 seconds and then rolls over to zero and begins to count up again in
minutes and seconds.
Timer Down (TIMER DN) is a resettable timer to allows the pilot to preset a time into the display and
will then count down. When the count down timer reaches zero, the timer display will be gin to blink
to alert the pilot that the preset time has expired. The timer will then begin to count up with a plus sign
(+) in front of the time. This enables the pilot to how far he is past his preset time. To set the time in the
TIMER DN rotate the SELECT knob to the lower right display quadrant, this area will begin to blink.
Rotate the DATA knob until the TIMER DN function is displayed. Press the ENTER pushbutton and
the seconds digits begin to blink. Turn the DATA knob until the desired time is in the display. When
entering time into the seconds, the time will roll over to the minutes. Rotating the SELECT knob
counterclockwise will place the cursor over the minutes. Entering minutes separately may be the
fastest way to get to a longer time.
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User Configurations allow pilots to set the STX 165 to display certain items to their preference. To set
the user configurations press and hold the IDT pushbutton while turning the SELECT knob counter
clockwise. Then press ENTER. The first configuration screen will appear. Rotating the DATA knob
counter clockwise will scroll the various user set up items.
TEMPUNIT: use the SELECT knob for temperatures to be displayed in either Celsius or Fahrenheit.
ALT UNIT: Rotate the SELECT knob for altitudes to be displayed in either Meters or Feet.
AUTO MODE ALT: This determines what altitude AGL the STX 165 will automatically transition
from Standby to ALT after initial turn on. It can be set in 25’ increments up to 900 feet. If 0 feet is
selected, the STX165 will turn on the ALT mode. To select an altitude Press the ENTER pushbutton.
The currently set altitude will blink. Use the DATA knob to select the desired altitude, and press
ENTER.
ICINGALERT: If the optional SANDIAST 78 OAT probe is installed, the pilot can selted a tempera-
ture at which an icing alert will be displayed. To program an icing alert temperature, Press the ENTER
pushbutton. The Temperature will begin to blink. Use the DATAknob to selected a desired icing alert
temperature. Icing Alert temperatures can be set from -5 to +5 degrees C or 23 to 41 degrees F.
EFT STARTALT: This determines what altitudeAGL the STX 165 will automatically start the EFT
timer. If theAltitude is set to 0, the EFT will begin counting at unit start up. To select an altitude Press
the ENTER pushbutton. The currently set altitude will blink. Use the DATAknob to select the desired
altitude, and press ENTER.
BRIGHTNESS: The STX 165 automatically dims the display for the ambient lighting conditions.
This feature allows the pilot to set the minimum intensity to which the STX165 will dim. To set a
minimum intensity, Press ENTER and turn the DATA knob until the minimum desired intensity is
displayed.
DEFAULTVFR: This display allows the pilot to set the squawk code that will be active whenever the
VFR pushbutton is pressed. This is factory set at 1200 which is the VFR squawk code for the US. To
change the VFR code, Press the ENTER pushbutton. The first digit in the code will blink, indicating it
can be changed. Rotate the DATA knob to select a new value. Rotate the SELECT knob to select the
second digit. Continue this until all digits have been changed to the new VFR code and then press
ENTER.
SET DEFAULTS: This will return all setting to the factory default setting. To reset all the user
setting, Rotate the SELECT knob counter clockwise, [YES] will be displayed. Press the ENTER
pushbutton. The setting have now been reset.
To exit the user set up mode, momentarily press the POWER pushbutton.
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