SANDIA aerospace STX 165 User manual

STX 165
User Manual
3700 Osuna Road NE
Suite 711
Albuquerque, NM 87109
www.sandia.aero
306105
Rev A
DRN434

This document and the information contained herein is the proprietary data of SANDIA aerospace Corpora-
tion. No part of this document may be transmitted, reproduced or copied in any form or by any means without
the prior written consent of SANDIA aerospace. Due to SANDIA aerospace’s continued product and quality
improvement programs, information contained in this document is subject to change without prior notice.
Copyright 2010 SANDIA aerospace Corporation, all rights reserved. Printed USA
Revision Date Description Approval
IR 20120222 MR102 L.Harrison
A 20130311 DRN 434 L. Harrison
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STX 165 Operation
The STX 165 is a Mode C transponder capable of transmitting 4096 different codes in response to ground radar
interrogations. All operations of the STX 165 are controlled through the front panel controls. The controls are
as follows:
Power/Mode Control
VFR Pushbutton Ident Pushbutton
Select Knob
Data Knob
Enter Pushbutton
The Power/Mode
Control
The STX 165 will come on anytime power is applied to the rear connector. It is recom-
mended that power to the STX 165 be supplied through a panel mounted avionics master
switch. The STX 165 can be turned off by pressing and holding the Power button for three
seconds. It can be turned on again by momentarily depressing the Power button.
The Power button has two additional functions. One is as an Escape mode. If the operator
is in a programing mode and wishes to escape to the main page, he can press the Power
button momentarily. This will cancel all programming and show the normal display page.
The power pushbutton is also used to start the counters. This is explained in the counter
section.
SBY: The STX 165 is in standby mode and will not respond to radar interrogations.
ON: The STX is on and responding to radar interrogations but is not reporting altitude.
This is often referred to as Mode A
ALT: The STX 165 is responding to radar interrogations with altitude information.
This is often referred to as Mode C
Data Knob
Enter Pushbutton
These are dual concentric knobs with a pushbutton action. The larger Select knob is a
momentary switch that is spring loaded. It can be turned clockwise and counter clockwise
and will return to center when released. It is used to move the cursor during Code selection
and to toggle through the display options in the lower left display ( PALT, DALT and OAT).
Note that DALT and OAT are only available if the optional Sandia OAT probe model STP
78 is installed.
The smaller inner knob is the Data knob and is used to select the digit value when program-
ing the squawk code and to select the counter function in the lower right display when not
in the code selection mode.
Photocell
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The VFR Pushbutton is use to select the VFR Squawk code. Pressing it a second time will
recall the previous code.
The VFR pushbutton has an additional function. Pressing and holding it for three seconds
will enlarge the squawk code display. When in this mode the functions on the bottom portion
of the display screen will no longer be displayed. Pressing and holding the VFR Pushbutton
for three seconds again will exit this mode. This function is useful in high sunlight condi-
tions, particularly with bubble canopies.
When power is rst applied to the STX 165, the SANDIA aerospace logo will be displayed along with the unit
version number (the last two digits of the part number), the Display software version (D) and the Main software
version (M). The current software versions can be seen on the SANDIA aerospace web site at www.sandia.aero.
IDT Pushbutton The IDT is the Ident pushbutton and is depressed when requested by ATC to Ident. The
STX 165 remains in the Ident mode for 22.5 seconds. When transmitting Ident, ID will be
displayed in the left portion of the display.
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After the software versions are displayed, the STX 165 display will revert to the normal operating mode. The up-
per left portion of the display will show the current transmitter Mode. The upper right portion of the display will
show the last code that was selected prior to shut down, the PressureAltitude (PALT) is displayed in the lower left
and Elapsed Flight Time (EFT) in the lower right of the display. The built-in encoder requires a warm up time
and the PALT value will show dashes until the proper internal temperature is reached.
The user can set the mode to come on in the ALT mode at start up or at a predetermined altitude differential after
takeoff. The same is true for the EFT display. See User Set Up for a discussion of these features.
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Code Selection
To select a new squawk code you will use the Data/Select knob and pushbutton:
Press the Enter Pushbutton, the rst digit in the squawk code will blink.
Rotate the smaller Data knob until the value of the codes rst digit is displayed.
Rotate the larger Select knob clockwise to the stop and then release. The second digit of the squawk code will
be blinking, indicating that it can be changed.
Continue repeating the above steps until you have selected the desired squawk code and then Press the Enter
Pushbutton.
The new squawk code has been selected and is now being reported to ATC.
Note: The select knob is a spring load alternate action knob. It can be
turnedboth clockwise andcounterclockwise andwill then return to center.
Mode Selection
To select the Mode of Operation you will use the Mode Control knob.
Rotate the Mode Control knob to select one of three transmitter Modes.
SBY Standby. The STX 165 is on but not responding to ATC interrogations
ON The STX 165 is on and replying in Mode A (No Altitude Reporting)
ALT The STX 165 is on and replying in Mode C (Altitude Reporting)

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Altitude/Temperature Displays
Altitude and temperature information is displayed in the lower left display quadrant. The operator can cycle
through the different information by turning the Select knob (the large right side knob).
Pressure Altitude The STX 165 has a built-in TSO’d altitude encoder. The output of the encoder is pressure
altitude and is displayed as PALT. It can be displayed in either feet or meters depending on
the user set up conguration
Density Altitude If an optional SANDIA aerospace OAT probe is installed with the STX 165 it will display
DensityAltitude, DALT. DALT is based on the current OAT and PressureAltitude. DALT
will be displayed in either feet or meters depending on the user set up conguration
OAT If an optional SANDIA aerospace STP 78 OAT probe is installed with the STX 165, it will
display the current OutsideAir Temperature in either degrees Fahrenheit or Celsius depend-
ing on the User Set Up selection.
Icing Alert If an optional SANDIA aerospace STP 78 OAT probe is installed with the STX 165, it will
display an Icing Alert in the upper right hand corner of the display when the temperature
reaches a user dened temperature. The Snow Flake symbol will blink for ten seconds once
the IcingAlert temperature is reached, then remain on solid until the temperature goes above
the preset temperature.
Pressure Altitude Density Altitude Outside Air Temp Icing Alert
Timers
The STX 165 has three timer functions that are displayed in the lower right hand corner of the display. These
are Elapsed Flight Time (EFT), an up counter (CNT UP) and a down timer (CNT DOWN). To select a timer
rotate the Data knob either clockwise or counter clockwise.
Elapsed Flight Time When the STX 165 is rst turned on the timer function will be initialized on the Elapsed
Flight Time (EFT) page. The EFT will begin counting at system turn on or at a predeter-
mined altitude set by the pilot in the User Set Up mode. (Note that this is the differential
altitude from when the STX 165 was rst turned on.). The EFT can only be reset by
turning the unit off.

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Counter Up
The Counter Up (CNT UP) allows the pilot to time various auxiliary functions. It can be activated and reset at
any time. To use the CNT Up function:
1. Rotate the Data Knob until CNT UP is displayed. It will initialize on 0:00 if has not been used
since system start up.
2. To start the CNT UP, press the Power/Mode control pushbutton.
3. Press the Power/Mode control pushbutton again and the timer will discontinue counting, and
hold the elapsed time.
3. To start a new timer function press, the Power/Mode control. The CNT UP will reset to zero and
begin counting up.
4. Pressing and holding the Enter pushbutton for three second will reset and hold the CNT UP at
0:00.
Counter Up
Counter Down
The counter down (CNT DOWN) allows the pilot to enter a specic time and then be alerted when that time
has expired. This timer is especially useful for timed approaches. When activated, the down timer will count
down to zero and then begin counting up. During the counting up phase, the time will be preceded by a plus
symbol (+).
1. Rotate the Data Knob until the CNT DOWN legend is displayed. You will note that the CNT
DOWN time default is one minute and zero seconds.
2. To program a new time, press and hold the Data knob for three seconds. The seconds will begin
to blink.
3. Turn the Data knob to enter the new time. Note that you can program seconds and minutes from
the seconds position as the time rolls over whenever you reach 60 seconds. You can also rotate
the Select knob to the minutes position if desired.
Counter Down

User Conguration
The STX 165 allows the user to select certain parameters to t their preferences. It is recommended the user only
change these congurations when on the ground. This will keep from interfering with pilot duties and ensure
uninterrupted response to ATC radar interrogations.
1. To enter the User Set UP mode the STX 165 must be in the SBY (Standby) mode.
2. Press and hold the IDT pushbutton while turning and holding the Select knob counterclockwise for 3
seconds (Note that the select knob will go to a hard stop when rotated approximately an eighth of a turn).
The display will read “USER SETUP MODE. PRESS ENTER TO CONTINUE.
3. Press the Enter pushbutton. Note that if the Enter Pushbutton is not pressed within ten seconds the STX
165 will exit the set up mode.
Note: The STX 165 must be in SBY mode to enter the User Set Up
Function.
The rst page displayed when entering the user Set Up mode is ALTITUDE UNIT. To access subsequent set up
pages, rotate the Data knob.
TEMP UNIT The STX 165 will display temperature in either degrees Fahrenheit or degrees Celsius.
The factory default setting is Fahrenheit. To select a different temperature unit:
While on the TEMP UNIT page rotate the Select knob counterclockwise to select Celsius
and clockwise to select Fahrenheit.
ALT UNIT The STX 165 can display altitude in either meters or feet. The category default is feet.
To select a different altitude value:
1. Select the ALT UNIT page.
2. Rotate the Select knob Counterclockwise to select Meters and Clockwise to select
Feet.
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A UTO MODE-C ALT
The STX 165 is designed to turn on in the Standby (SBY) Mode. The user can select an altitude at
which the STX 165 will automatically select Mode-C (ALT) Mode. This altitude is the differential
altitude from when the STX 165 was rst turned on. To select an Auto On altitude:
1. Rotate the Data knob to select the AUTO MODE CALT page.
2. Press the Enter Pushbutton. The Auto Alt On altitude will be blinking.
3. Rotate the Data knob to select the desired Auto On Altitude. The altitude will change in
25 foot or 10 meter increments.
4. Press the Enter Pushbutton
Note:TheAutoOnAltitudeand theEFTAltitudearethe differentialAltitudes
from when the STX 165 is turned on. For example if the Auto On altitude is
set for 200 feet and the STX 165 is turned on at 1200 feet, the STX 165 will
automatically select ALT Mode at 1400 feet.
EFT START ALT
Note: If 0 (zero) feet or meters is selected in AUTO MODE C ALT, the STX
165 will turn on in the ALT Mode. This is generally not recommended. If
OFF is selected, the pilot will be required to select the ON orALT Mode.
The STX 165 starts with the EFT displayed in the lower right hand corner of the display.
The user can set the EFT to begin counting at turn on or at a specied Alt above the turn on
altitude. It the EFT is set at 0, then the EFT will begin counting at turn on. To set the EFT
start altitude:
1. Rotate the Data knob to select the EFT STARTALT page.
2. Press the Enter Pushbutton. The EFT start altitude will be blinking.
3. Rotate the Data knob to select the desiredAuto OnAltitude. The altitude will change
in 25 foot or 10 meter increments.
4. Press the Enter Pushbutton
ICING ALERT
Ifa SANDIA aerospace STP78 OATprobe is installed with the STX165 the unit willprovide
an icing alert. The icing alert is a snow ake that appears in the upper right corner of the
display whenever a user preset temperature is reached. To set the Icing Alert temperature:
1. Rotate the Data knob to select the ICING ALERT page.
2. Press the Enter Pushbutton. The brackets will extinguish and the Temperature will
blink
3. Rotate the Data knob until the desire Icing Alert temperature is displayed.
4. Press the Enter Pushbutton.
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MIN BRIGHTNESS The STX 165’s digital display automatically adjusts to ambient light conditions. The
minimum intensity to which the STX 165 will adjust is set by the user. To set the mini-
mum intensity:
1. Rotate the Data knob to select the MIN BRIGHTNESS page.
2. Press the Enter Pushbutton. The brackets will extinguish indicating the Min
Brightness can be adjusted.
3. Rotate the Data knob clockwise to increase the minimum brightness and counter-
clockwise to decrease the minimum brightness.
4. Press the Enter pushbutton to select the new setting.
Default VFR The STX 165 comes preset with 1200 as the VFR squawk code. In some instances a dif-
ferent code is desirable for the VFR squawk. To change the VFR squawk code:
1. Rotate the Data knob to select the DEFAULT VFR page.
2. Press the Enter knob. The brackets will extinguish and the rst digit of the
squawk code will be blink, indicating it can be programmed.
3. Rotate the Data knob to select the rst digit of the desired squawk code.
4. Rotate the Select knob. The rst digit will go solid and the second digit will
blink indicating it can be changed.
5. Continue as above unit all digits are changed to the desired code.
6. Press the Enter Pushbutton. The blinking will stop and the brackets will
return indicating the code has been selected
Note: It is the pilot’s responsibility to insure that the proper squawk code is
selected.
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3700 Osuna Road NE
Suite 711
Albuquerque, NM 87109
www.sandia.aero