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MCL TN440-3, Technical Note

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MCL TN440-3 Technical Note Download Page 7

TECHNICAL NOTE – OPERATION OF MT4400 TWTA  

08/10/2004 

 

 

TN4400-3 

MCL, INC. 

7 of 36 

 
 

 

 

 
 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 parts can reach 
several hundred degrees centigrade. 

 
 

 

 
 

RF OVERDRIVE 

 

The unit may be damaged by drive levels as low as -17 dBm for the 
MT4400 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. 

 
 
 

 

 
 

RF OVERDRIVE – BLOCK UP CONVERTER OPTION 

 

Never operate the MT4400 without the external semi-rigid cable that 
connects to the tube input connector.  Operating without this cable may 
lead to a tube overdrive condition. 

 
 

WARNING 

WARNING 

WARNING 

CAUTION 

CAUTION 

Summary of Contents for TN440-3

Page 1: ...TN4400 3 Technical Note Operation of MT4400 TWTA August 10 2004 Mark Schmeichel 8 13 04 Engineering Date Lars E Agner 8 16 04 Sales Date...

Page 2: ...terface 9 3 4 Controls Status via Communications Protocol 9 4 0 HPA OPERATION 12 4 1 HPA Control Modes 12 4 2 HPA Operating Modes 14 4 3 RF On Off Control 16 4 4 Faults Alarms 16 4 5 HPA Gain Control...

Page 3: ...WTA 08 10 2004 TN4400 3 MCL INC 3 of 36 LIST OF APPENDICES APPENDIX A 40A1546 CSP Protocol Specification APPENDIX B 40A1715 SABus Compatible Protocol Specification APPENDIX C 46A0204 CSP Command Set A...

Page 4: ...s 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 mainte...

Page 5: ...ltage 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...

Page 6: ...n 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...

Page 7: ...ed parts can reach several hundred degrees centigrade RF OVERDRIVE The unit may be damaged by drive levels as low as 17 dBm for the MT4400 depending upon the settings of the system attenuator Please a...

Page 8: ...remote panel and or computer interface There is a limited amount of controls locally however due to safety concerns these controls will only be available when activated 3 1 Discrete Status On the MT4...

Page 9: ...owing signals WG Pressure Fault Input External Interlock Fault Input External RF Inhibit Input Sum Fault Indicator Output Sum Alarm Indicator Output 3 4 Controls Status via Communications Protocol The...

Page 10: ...The Summary Alarm Flag is set to true when the HPA has an alarm state that can lead to a fault condition if it is not corrected 3 4 7 Reset Command Summary Fault Flag When this command is sent the fau...

Page 11: ...et to false the amplifier is in manual switching mode 3 4 16 Antenna Command Flag When this command is sent this HPA will be put into the antenna port of the RF switch When the Flag is set to true the...

Page 12: ...ded through the diagnostic interface 3 4 22 Communications Set Up Communications are verified and set up via the Diagnostic Port Please use the Diagnostic Program that came with the HPA To set up or v...

Page 13: ...t The Protocol specifications and command sets for both CSP SAbus are attached to this document as appendices 4 1 4 Computer Control 4 1 4 1 Control Priority While the HPA is in the Computer mode the...

Page 14: ...for these states is shown in the table below STATUS FROM BFC STATE FILAMENT OFF DELAY STBY XMT SELD XMT SUM FAULT DC power on no operator action has been taken ON OFF OFF OFF OFF OFF DC power on no op...

Page 15: ...ransmit This state occurs after a Transmit command Local Remote or Computer has been issued when the TWTA was in the Standby mode During this state all TWTA circuitry will be activated including the h...

Page 16: ...ow Alarm will be delayed for two seconds 4 4 Faults Alarms There are two types of warning status signals produced by the MT4400 An alarm WILL NOT affect the operating state of the HPA A fault will shu...

Page 17: ...ended earth station or during a degassing operation or if the tube is nearing the end of its life the Fault Counter may be turned on to allow the HPA to automatically reset the tube faults and return...

Page 18: ...example a 3 0 dB change of the input attenuator will not necessarily produce a 3 0 dB change at the HPA output 4 5 2 Auto Power Function Not available on some Multi Band HPA Please Consult MCL Auto Po...

Page 19: ...Remote Interface was to set the Auto Power level to 0000W If the RF attenuator is manually adjusted 4 5 3 Hold Power Not available on some Multi Band HPAs Please Consult MCL The MT4400 remote panel c...

Page 20: ...ng and uploading data to the HPA The diagnostic interface program has information built into the Help menu to give the operator additional assistance The Windows cut and paste functions are enabled on...

Page 21: ...nostic Interface program click on the Settings tab see the following figure 2 Click on the Download All Settings button to refresh the settings display 3 To save the data to disc once the status is do...

Page 22: ...and not carrying traffic or an interruption in service may occur The HPA must be in a maintenance mode to upload settings or an interruption of service may occur 2 On the Diagnostic Interface program...

Page 23: ...en on the Save menu select Event Log The diagnostic program will automatically produce a file name which includes the HPA serial number events and today s date 4 The add to database box when checked w...

Page 24: ...k on the Cal Tables tab see the following figure 2 Click on the Download Tables button 3 Once the tables are done downloading click on the File menu select Save on that menu then on the Save menu sele...

Page 25: ...the following figure 2 Click on the Download button to refresh the status 3 To save the data to disc once the status is done downloading click on the File menu select Save on that menu then on the Sa...

Page 26: ...ct the HPA from the drop down list on the left side and then select the parameter to graph from the list on the right side There is no timescale Data points are equally spaced across the bottom ordere...

Page 27: ...itch position As a result the HPAs must pass information back and forth so that switchover operation is continuous and uninterrupted The switchover logic will use inputs from the Remote Interface Comp...

Page 28: ...age power supply will remain on J6 contains the Remote Port and J7 the Computer Port 4 11 Prevention of Excessive RF Input Power As is well known driving a TWT past saturation will damage the tube Sat...

Page 29: ...TECHNICAL NOTE OPERATION OF MT4400 TWTA 08 10 2004 TN4400 3 MCL INC 29 of 36...

Page 30: ...t Alternately set exciter at maximum and insert attenuation in the line to limit power available at the TWTA 3 MT4400 Trip Levels The Tube Overdrive Fault and the Tube Overdrive Alarm levels were set...

Page 31: ...n the cabinet and the cabinet is firmly bolted in place 4 Ground strap earth attached to safety ground tie point in the system cabinet lower rear 5 Appropriate AC input voltage and frequency has been...

Page 32: ...of adjustment or the fault conditions are no longer recognizable If these conditions should exist no further attempt should be made to use the amplifier system until the defective circuitry or adjustm...

Page 33: ...he high voltage The Transmit Flag will be set to true 8 Send the RF On Command 9 Set the exciter output to RF On MT4400 Block Up Converter Option Be sure to allow ample warm up time before attempting...

Page 34: ...er proof seal The MT4400 gain control should then be used in the future to make adjustments to the system output power 14 Allow the system to thoroughly stabilize for no less than 5 hours 15 If it is...

Page 35: ...to an M C system and you wish to keep the HPA on the bus do not perform the following steps 4 Let HPA remain on to cool down until the tube temperature is below 35 C 5 Turn off the Main AC Power switc...

Page 36: ...MT4400 TWTA 08 10 2004 TN4400 3 MCL INC 36 of 36 APPENDIX A 40A1546 CSP Protocol Specification APPENDIX B 40A1715 SABus Compatible Protocol Specification APPENDIX C 46A0204 CSP Command Set APPENDIX D...

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