MCL MT4000 TWTA Instruction Manual

TN4000-3
Technical Note
Operation of MT4000 TWTA
October 24, 2003
Mark Schmeichel 10/24/03
Engineering Date

TECHNICAL NOTE – OPERATION OF MT4000 TWTA 10/24/03
TN4000-3 MCL, INC. 2 of 46
TABLE OF CONTENTS
1.0 SAFETY SUMMARY.......................................................................................................4
1.1 Definitions of Warnings, Cautions, and Notes...........................................................4
1.2 General Safety Precautions......................................................................................... 5
1.3 List Of Hazards .......................................................................................................... 6
2.0 SCOPE................................................................................................................................8
3.0 CONTROLS & INDICATORS ....................................................................................... 8
3.1 Discrete Controls & Indicators...................................................................................9
3.2 Front Panel Display & Screen Content ....................................................................13
4.0 HPA OPERATION.........................................................................................................21
4.1 HPA Control Modes................................................................................................. 21
4.2 HPA Operating Modes.............................................................................................24
4.3 RF On/Off Control...................................................................................................25
4.4 Faults & Alarms.......................................................................................................26
4.5 HPA Gain Control.................................................................................................... 29
4.6 Diagnostic Interface..................................................................................................31
4.7 Optional Local Interface Override............................................................................38
4.8 Optional Linearizer...................................................................................................39
4.9 Switchover Interface J7 and Front Panel Controls...................................................39
4.10 User Interface J6....................................................................................................... 40
4.11 Prevention of Excessive RF Input Power.................................................................40
5.0 INITIAL TURN ON OF THE HPA ..............................................................................42
5.1 Initial Turn-On Check List....................................................................................... 42
5.2 Operating Caution List............................................................................................. 43
5.3 Power-Up Procedure ................................................................................................44
6.0 SHUT DOWN PROCEDURE........................................................................................46

TECHNICAL NOTE – OPERATION OF MT4000 TWTA 10/24/03
TN4000-3 MCL, INC. 3 of 46
LIST OF APPENDICES
Appendix A- - 40A1546 CSP Protocol Specification
Appendix B - 40A1715 SA Bus Compatible Protocol Specification
Appendix C - 46A0204 CSP Command Set
Appendix D - 46A0203 SA Bus Command Set

TECHNICAL NOTE – OPERATION OF MT4000 TWTA 10/24/03
TN4000-3 MCL, INC. 4 of 46
1.0 SAFETY SUMMARY
1.1 Definitions of Warnings, Cautions, and Notes
WARNING AND CAUTION statements have been strategically placed in the text to emphasize
certain steps or procedures for the protection of personnel (WARNING) or equipment
(CAUTION). A WARNING or CAUTION once provided would apply each time the related step
is repeated, regardless of the number of times the WARNING or CAUTION is repeated
throughout the text. Prior to starting any task, THE WARNINGS or CAUTIONS included in the
text for that task should be reviewed and understood.
An operating or maintenance procedure, practice, condition, statement, etc., which
if not strictly observed, could result in injury to or death of personnel.
An operating or maintenance procedure, practice, condition, statement, etc., which if
not strictly observed, could result in damage to or destruction of equipment, or loss of
mission effectiveness.
NOTE
An essential operating or maintenance procedure, condition,
or statement which must be highlighted.
CAUTION
WARNING

TECHNICAL NOTE – OPERATION OF MT4000 TWTA 10/24/03
TN4000-3 MCL, INC. 5 of 46
1.2 General Safety Precautions
The following are general safety precautions and instructions that personnel must understand and
apply during many phases of operation and maintenance to ensure personnel safety and health
and the protection of property. Portions of this information may be repeated in certain chapters
of this publication for emphasis.
KEEP AWAY FROM LIVE CIRCUITS
Operating personnel must at all times observe safety regulations. Do not replace components or
make adjustments inside the equipment with the voltage supply turned on. Under certain
conditions, dangerous potentials may exist when the power control is in the off position, due to
charges retained by capacitors. To avoid injuries, always remove power from, discharge, and
ground a circuit before touching it. Adhere to all lock out/tag out requirements.
DO NOT SERVICE OR ADJUST ALONE
Do not attempt internal service or adjustment unless another person capable of rendering aid and
resuscitation is present.
RESUSCITATION
Personnel working with or near dangerous voltage shall be trained in modern methods of
resuscitation.
COMPRESSED AIR
Use of compressed air for cleaning can create an environment of propelled foreign particles. Air
pressure shall be reduced to less than 30 psi and used with effective chip guarding and personnel
protective equipment.

TECHNICAL NOTE – OPERATION OF MT4000 TWTA 10/24/03
TN4000-3 MCL, INC. 6 of 46
1.3 List Of Hazards
The operation of this amplifier may involve some of the following hazards; any of them could
result in serious harm to personnel if proper safety precautions are not taken.
HIGH VOLTAGE
Lethal Voltages up to 15,000 Volts are present in this amplifier when it is
operating. USE EXTREME CAUTION when inside the unit. Do not insert objects
through air intake screen on rear of drawer. When testing, always ground the
drawer chassis.
RF RADIATION
Exposure to RF radiation may cause serious bodily injury possibly resulting in
blindness and death. Cardiac pacemakers may be affected. Always terminate both
the RF input and RF output, even during tests, which involve no RF drive, to avoid
the RF hazard should the TWTA oscillate.
BERYLLIUM OXIDE
The dust or fumes from Beryllium Oxide (BeO) ceramics used in microwave tubes
are highly toxic and can cause serious injury or death.
WARNING
WARNING
WARNING

TECHNICAL NOTE – OPERATION OF MT4000 TWTA 10/24/03
TN4000-3 MCL, INC. 7 of 46
IMPLOSION HAZARD
Ceramic windows from microwave tubes can shatter on impact or crack in use
resulting in injury from Beryllium Oxide dust or fumes.
X-RAY RADIATION
High voltage tubes can produce dangerous, possibly fatal X-Rays.
HOT SURFACES
Surface temperature of tubes and other air cooled ports can reach several hundred
degrees centigrade.
RF OVERDRIVE
The unit may be damaged by drive levels as low as -17 dBm for the M/N MT4000
depending upon the settings of the system attenuator. Please apply RF with caution.
Always terminate RF input and output ports properly when AC power is supplied to
the TWTA.
CAUTION
WARNING
WARNING
WARNING

TECHNICAL NOTE – OPERATION OF MT4000 TWTA 10/24/03
TN4000-3 MCL, INC. 8 of 46
2.0 SCOPE
This document and its appendices will described the controls, operator interfaces, and operating
procedures for a MT4000 TWTA. This manual assumes a familiarity and working experience
with high power microwave RF amplifiers.
The MCL MT4000 is designed for long and reliable life under a variety of environmental
conditions. All components utilized in this system are conservatively rated and selected for high
reliability and maximum use of existing designs. Mechanical and electrical safeguards are
utilized throughout the system to insure safety of operating personnel.
3.0 CONTROLS & INDICATORS
Complete operational control and status is available at the local control display panel, remote
panel, or computer interface. However, due to safety concerns certain controls will only be
available on the Local panel.
The user at the TWTA front panel will be provided system status and diagnostics through a four
line vacuum fluorescent display (VFD), membrane panel CCA LED s, membrane panel CCA
buttons, and a digital encoder used to adjust the amplifier parameters.

TECHNICAL NOTE – OPERATION OF MT4000 TWTA 10/24/03
TN4000-3 MCL, INC. 9 of 46
3.1 Discrete Controls & Indicators
The indicators & controls described in this section are provided on the HPA front panel. Further
description of these functions follows in later sections of this document.
3.1.1 Filament Off Button/LED
When this button is activated, from any state except Transmit, the Filament Power Supply will be
turned off. When illuminated this Yellow LED will indicate that the HPA is in the Filament Off
state.
3.1.2 Delay LED
Yellow LED which when illuminated will indicate the HPA is going through a filament warm up
cycle and is not yet in Standby.
3.1.3 Standby Button/LED
There are two functions for this button. First, if pressed while the HPA is in the Filament Off
state filament delay will be initiated, the Yellow LED in the button will be flashing. Second, if
pressed while the HPA is in the Transmit state the HPA will switch to the Standby state, the
Yellow LED in the button will be continuously illuminated.
3.1.4 Transmit Button/LED
While no faults are present, if this button is activated the HPA will cycle into the HV on state.
When the Green LED inside the button is continuously illuminated, the HPA is in transmit. If
flashing, transmit has been selected, but the amplifier is still in filament delay, and upon
completion of filament delay the HPA will go into Transmit.
3.1.5 Summary Alarm LED
Yellow LED when illuminated the HPA has an alarm state that can lead to a fault condition if it
is not corrected.
3.1.6 Reset Button & Summary Fault LED
When this button is activated the a fault reset will be initiated. When the Red LED inside the
button is illuminated, the HPA has a fault and the high voltage is turned off.
3.1.7 RF On Button/LED
When this button is activated the SSA RF switch will be put into the ON state if no other
interface is causing a RF Off state. When the Green LED inside the button is illuminated, the
SSA RF switch is enabled.

TECHNICAL NOTE – OPERATION OF MT4000 TWTA 10/24/03
TN4000-3 MCL, INC. 10 of 46
3.1.8 RF Off Button/LED
When this button is activated the HPA will disable the SSA RF switch. When the Yellow LED
inside the button is illuminated, the SSA RF switch is disabled.
3.1.9 Computer Rx LED
The Yellow LED will illuminate with data received from the computer port.
3.1.10 Computer Tx LED
The Green LED will illuminate with data transmitted to the computer port.
3.1.11 Remote Rx LED
The Yellow LED will illuminate with data received from the remote port.
3.1.12 Remote Tx LED
The Green LED will illuminate with data transmitted to the remote port.
3.1.13 RF High LED
The Yellow LED will illuminate when the detected forward power exceeds the user specified
level.
3.1.14 RF Low LED
The Yellow LED will illuminate when the detected forward power is lower than the user
specified level.
3.1.15 Local Button/LED
When this button is activated the HPA will allow the operator at the front panel to control the
HPA operating configuration. When the Green LED inside the button is illuminated, the
amplifier is controlled from the HPA front panel.
3.1.16 Computer Button/LED
When this button is activated the HPA will allow the device on the computer interface to control
the HPA operating configuration. When the Yellow LED inside the button is illuminated, the
amplifier is controlled via the computer serial port.

TECHNICAL NOTE – OPERATION OF MT4000 TWTA 10/24/03
TN4000-3 MCL, INC. 11 of 46
3.1.17 Remote Button/LED
When this button is activated the HPA will allow the device (remote panel) on the remote
interface to control the HPA operating configuration. When the Yellow LED inside the button is
illuminated, the amplifier is controlled via the remote serial port.
3.1.18 Auto Button/LED
When this button is activated both HPAs in the 1:1 switchover will be put into the auto switching
mode. When the Green LED inside the button is illuminated the amplifier is in Automatic
Switching mode.
3.1.19 Manual Button/LED
When this button is activated both HPAs in the 1:1 switchover will be put into the manual-
switching mode. When the Yellow LED inside the button is illuminated the amplifier is in
manual switching mode.
3.1.20 Antenna Button/LED
When this button is activated, though the 1:1 switchover this HPA will be put into the antenna
port of the RF switch. When the Green LED inside the button is illuminated the amplifier is
switched to the antenna port of the RF switch.
3.1.21 Load Button/LED
When this button is activated, though the 1:1 switchover this HPA will be put into the dummy
load port of the RF switch. When the Yellow LED inside the button is illuminated the amplifier
is switched to the dummy load port of the RF switch.
3.1.22 RF Low Switching LED
The Green LED will illuminate when RF Low alarm switching for the Auto Switching mode has
been enabled through the Switchover interface.
3.1.23 Hold Power Button/LED
When this button is activated the HPA RF output power will be automatically regulated by the
Auto Power function. When the Green LED inside the button is illuminated this indicates the RF
output power is being automatically regulated by the Auto Power function.
3.1.24 Units Select Button
When this button is activated it will cause the HPA to toggle the displayed units of three
parameters on the HPA front panel between Watts, dBm, or dBW. The three parameters are RF
Forward Power, RF Reflected Power, and Tube Drive Power. The units for no other parameter
will be affected including the trip levels for these parameters.

TECHNICAL NOTE – OPERATION OF MT4000 TWTA 10/24/03
TN4000-3 MCL, INC. 12 of 46
3.1.25 Accept Button
This button will be used to select adjustable parameter on any screen.
3.1.26 Menu Select Button
This button is used to move between different menus on the display.

TECHNICAL NOTE – OPERATION OF MT4000 TWTA 10/24/03
TN4000-3 MCL, INC. 13 of 46
3.2 Front Panel Display & Screen Content
This figure shows an overview of the TWTA screens and the flow between these screens. The
following paragraphs describe each screen and how the operator will move between them.

TECHNICAL NOTE – OPERATION OF MT4000 TWTA 10/24/03
TN4000-3 MCL, INC. 14 of 46
3.2.1 Title Screen
The title screen will be displayed when the TWTA first powers on and will remain on while
startup testing and a lamp test is performed. This will not exceed 5 seconds.
3.2.2 Encoder-Adjustment Knob
The adjustment knob along with the Accept & Menu Select buttons will be used to move from
screen to screen, to move from parameter to parameter on a screen, and to adjust parameters that
are displayed on these screens.
3.2.3 Normal Operating Screen
The normal operating screen is activated automatically after the title screen disappears and there
are no faults or alarms present. During filament delay, the first line of the normal operating
screen will display the remaining filament delay time. After filament delay time ends, the RF
forward power value will be displayed on the first line of the display. However, if filament delay
has ended and the RF On/Off state is OFF, RF OFF will be displayed on the first line. The
second line will display reflected power in the same units as forward power. If Transmit Selected
is active, the second line will display XMT SELECTED. The third line will always display helix
current and voltage. The fourth line is used to view numeric (meter) values. To change the
parameter displayed on the fourth line rotate the knob CW or CCW. CW will rotate through the
list shown in the figure from top to bottom and CCW will be bottom to top. By pressing the
Menu Select button from this screen the menu screen (see the next paragraph) will be displayed.

TECHNICAL NOTE – OPERATION OF MT4000 TWTA 10/24/03
TN4000-3 MCL, INC. 15 of 46
3.2.4 Main Menu Screen
This screen is accessed from the normal screen. When the menu screen shown below is
displayed the operator can select from the functions listed on this menu. Though there are six
menu selections, the screen can only display four at a time. By rotating the knob CW these
selections will scroll up one at a time, and CCW down one at a time. Once the cursor is pointing
at the desired selection the operator will press the Accept button, which will cause the selected
screen to be displayed. If the operator were to press the menu select button from this screen the
normal screen would be displayed again.
3.2.5 Gain Adjust Screen
This screen is accessed from the menu screen. When the screen shown below is displayed the
operator can use the adjustment knob to change the HPAs input attenuator setting. If the operator
were to press the menu select button from this screen the menu screen would be displayed again.
Since the attenuator is in the input side of the HPA there is not a direct correlation between input
attenuation and output power in dBm or dBW. The difference is due to the gain compression of
the HPA.

TECHNICAL NOTE – OPERATION OF MT4000 TWTA 10/24/03
TN4000-3 MCL, INC. 16 of 46
3.2.6 Adjustment Menu Screen
This screen is accessed from the menu screen. When the screen shown below is displayed the
operator can select which parameter to modify from those listed on this menu. Notice there are
seventeen menu selections, but the screen can only display four at a time. By rotating the knob
CW these selections will scroll up one at a time, and CCW down one at a time. Once the cursor
is pointing at the desired selection the operator will press the Accept button. This will cause the
selected screen to be displayed. If the operator were to press the menu select button from this
screen the menu screen would be displayed again.
3.2.7 Adjustment Edit Screen
These screens are accessed from the adjustment menu screen. The screen shown below is a
typical EDIT screen for an adjustable parameter. While one of these screens is displayed the
operator can use the adjustment knob to change the parameter shown on the fourth line. The
adjusted value will take effect once the accept button is pressed. The third line is the value of the
parameter before it is adjusted. The second line is the meter associated with the parameter being
adjusted. The first line is the name of the parameter being adjusted. If the operator were to press
the menu select button from this screen the adjustment menu screen would be displayed again.

TECHNICAL NOTE – OPERATION OF MT4000 TWTA 10/24/03
TN4000-3 MCL, INC. 17 of 46
3.2.8 Event Log Screen
This screen is accessed from the menu screen. When the screen shown below is displayed the
most recent event in the log will be presented.
The event log is stored in Non-Volatile memory on the HPA and will contain operational state
changes, alarms, and faults, which have occurred in the HPA. The event log will contain the
event name with a date and time stamp for when the event occurred. Events that can be stored in
the log are listed in the following table. If one of the user adjustable trip levels are exceeded
causing an event entry, the level that was exceeded will also be stored in the log and presented on
the fourth line of the display.
The time resolution of the log will be to the nearest second (±1 second). The event log is able to
store 200 events. If the log size exceeds the available memory size the oldest events will scroll
out of the log. The log is purged only through a diagnostic interface command. The event log can
be downloaded through the diagnostic interface.
The operator can use the adjustment knob to scroll through the events in time sequence one at a
time. By rotating the knob CW these selections will scroll backwards in time, and CCW forward
in time. If the operator were to press the menu select button from this screen the menu screen.

TECHNICAL NOTE – OPERATION OF MT4000 TWTA 10/24/03
TN4000-3 MCL, INC. 18 of 46
FAULTS
Tube Temp Switch Chassis Interlock RF Reflected Tube Overdrive
Helix Surge User Interlock W.G. Arc HV Over Volt
Filament Under Current Tube Temp Analog HV Primary Current P.S. Temperature
Helix Run W.G. Pressure Arc Test Failed HV Under Volt
ALARMS (EACH ALARM HAS AN ON & OFF EVENT)
RF Low AC Low Line RF Reflected Exciter
RF High Tube Overdrive Tube Temp Analog P.S. Temperature
RF Interface Comm Switchover & User
Comm PS Interface Comm Blower Failed
+5V Power Supply +15V Power Supply -15V Power Supply RF Switch Failed
Attenuator Uncalibrated RF Forward Uncalibrated RF Reflected Uncalibrated Tube Drive Uncalibrated
OPERATING STATES
End of Log Standby Local RF Off Local RF On
Transmit Remote RF Off Remote RF On
Local Override Off Transmit Selected Computer RF Off Computer RF On
Local Override On Filament Delay On User RF Off User RF On
Power Off Power On Remote
Reset Filament Off Local Computer
SWITCHOVER OPERATING STATES
Auto Manual This HPA to Ant This HPA to D.L.
Second HPA SWOV
Fault SWOV RF Off SWOV RF On
3.2.9 Fault Log Screen
The fault log screen will look identical to the event log screen and will operate in the same
manner except that all alarms, operating states, and switchover operating states will be filtered
from the display. This screen will only present those events, which cause a Summary Fault and
Fault Reset.

TECHNICAL NOTE – OPERATION OF MT4000 TWTA 10/24/03
TN4000-3 MCL, INC. 19 of 46
3.2.10 Coupling Factor Screen
On this screen the operator can edit or view the frequency and coupling factor for up to eight
frequencies for the TWTA output sample port. These coupling factors are a convenience for the
operator and are not used in any calculations within the TWTA logic. This screen is accessed
from the menu screen. When the screen shown at the top of the figure below is displayed the
operator can select which line to modify from those listed on this menu. Though there are eight
menu lines to select, the screen can only display four at a time. By rotating the knob CW these
selections will scroll up one at a time, and CCW down one at a time. Once the cursor is pointing
at the desired selection the operator will press the Accept button. This will cause the edit screen
for the selected line to be displayed (see the next paragraph). If the operator were to press the
menu select button from this screen the menu screen would be displayed again.
3.2.11Coupling Factor Edit Line Screen
This screen is accessed from the coupling factor screen. When the screen shown in the middle of
the figure above is displayed the operator can select the frequency or the coupling factor to edit.
By rotating the knob the cursor will alternate between the two parameters. Once the cursor is
pointing at the desired selection the operator will press the Accept button, this will cause the Edit
Parameter screen to be displayed (see the next paragraph). If the operator were to press the menu
select button from this screen the coupling factor screen would be displayed again.

TECHNICAL NOTE – OPERATION OF MT4000 TWTA 10/24/03
TN4000-3 MCL, INC. 20 of 46
3.2.12Coupling Factor Parameter Edit Screen
This screen is accessed from the coupling factor edit line screen. The screen shown at bottom of
the figure above is a typical EDIT screen for coupling factor parameters. While one of these
screens are displayed the operator can use the adjustment knob to change the parameter shown on
the fourth line. The adjusted value will take effect once the accept buttons is pressed. The third
line is the value of the parameter before it is adjusted. If the operator were to press the menu
select button from this screen the coupling factor edit line screen would be displayed again.
These coupling factor parameters can be adjusted from only the Local panel.
3.2.13 Communications Set Up Screen
This screen will display the configuration for both the remote and computer interfaces. This
screen is accessed from the menu screen. When the screen shown at the top of the figure below is
displayed the operator can select which parameter to modify from those listed on this menu.
Notice there are seven menu parameters to select from, but the screen can only display four at a
time. By rotating the knob CW these selections will scroll up one at a time, and CCW down one
at a time. Once the cursor is pointing at the desired selection the operator will press the Accept
button. This will cause the edit screen for the selected parameter to be displayed. If the operator
were to press the menu select button from this screen the menu screen would be displayed again.
3.2.14 Communications Parameter Edit Screen
This screen is accessed from the communications set up screen. The screen shown in the bottom
of the figure above is a typical EDIT screen for Remote or Computer interface communications
parameters. While one of these screens are displayed the operator can use the adjustment knob to
change the parameter shown on the fourth line. The adjusted value will take effect once the
accept buttons is pressed. The third line is the value of the parameter before it is adjusted. If the
operator were to press the menu select button from this screen the communications set up screen
would be displayed again.