COBHAM VEPA-2W Operation Manual Download Page 1

Page: 1 / 21

100-M0167X2

1 of 21

Cobham Tactical Communications and Surveillance
1916 Palomar Oaks Way, Suite 100, Carlsbad, CA 92008
Tel: 760-496-0055
FAX: 760-496-0057

GMS Inc. doing business as Cobham Tactical Communications and Surveillance

www.cobham.com/tcs

Technical Operations Manual

The most important thing we build is trust.

VEPA-2W Linear Power Amplifier

Summary of Contents for VEPA-2W

Page 1: ...Palomar Oaks Way Suite 100 Carlsbad CA 92008 Tel 760 496 0055 FAX 760 496 0057 GMS Inc doing business as Cobham Tactical Communications and Surveillance www cobham com tcs Technical Operations Manual...

Page 2: ...business as Cobham Tactical Communications and Surveillance www cobham com tcs REVISION HISTORY Version Date Author Comments X1 10 01 11 Nathan Moore Marcio Koptcke Initial release X2 02 15 12 Nathan...

Page 3: ...DE OR LOW CURRENT MODE 9 4 2 PA ENABLE Fast Switching Capable 9 4 3 VSWR RF OVERDRIVE AND OVER TEMERATURE PROTECTION CIRCUITS 9 5 OPERATIONAL INSTRUCTIONS 10 5 1 EXTERNAL CONNECTIONS 10 5 2 CONNECTING...

Page 4: ...16 Figure 12 SK Band Gain 16 Figure 13 SK Band Gain Change over Temp 16 Figure 14 C2 Band Gain 17 Figure 15 C2 Band Gain Change over Temp 17 Figure 16 LD Band Current 18 Figure 17 L2 Band Current 18 F...

Page 5: ...ld be avoided as it may induce oscillatory voltage fluctuations that might damage the amplifier The Power Amplifier is reversed polarity protected 1 3 PA ENABLE Fast Switching The VEPA 2W incorporates...

Page 6: ...from accidental overdrives High and sudden overdrives will damage the PA and therefore all care should be taken to avoid overdrive conditions The operator should carefully set the input power before c...

Page 7: ...General Specifications Parameter Specification DC input voltage Vdc 9 32 Mechanical Dimension without heat sink 2 1 L x 3 0 W x 0 6 H 5 3 cm x 7 6 cm x1 52 cm Weight lbs 0 300 grams 136 Base plate Tem...

Page 8: ...8 31 3 31 8 29 2 31 32 5 30 8 32 3 34 3 Flatness dB 1 2 1 4 0 6 0 7 1 1 1 2 0 8 0 9 0 5 0 6 1 0 1 1 1 4 1 7 Current 12 Vdc on 50 Load A 1 33 1 44 1 18 1 28 1 32 1 52 1 25 1 4 1 2 1 3 1 15 1 22 1 32 1...

Page 9: ...esigned have a LVTTL compatible enable pin PIN 5 The VEPA 2W was designed for fast switching applications with an ON time 100ns and an OFF time of 50ns For C2 band ON time 150ns and an OFF time of 100...

Page 10: ...2W baseplate temperature has dropped by 5 C from the trip point of 75 C In Normal operation the green LED see fig 1 is ON When the RF switch opens the LED color turns red as well as the FAULT 2 PIN2...

Page 11: ...n the 9 32 Vdc range Make sure the power supply is capable of supplying the current required The VEPA 2W will draw 110mA when in standby mode LVTTL logic low The VEPA 2W PA draws about 1 5 A at 12 Vdc...

Page 12: ...Isolator Optional This heat sink is typically shipped to customer for evaluation purposes Fig 2 shows also a test cable which includes a switch to select the mode of operation High Linearity or High...

Page 13: ...ould be about 3 dBm or less For a detailed explanation on the use of the VMT transmitter refer to the applicable manuals 5 4 USING A TRANSMITTER PA COMBINATION 5 4 1 The old FM approach The methodolog...

Page 14: ...ount of back off which will give the required linearity For the sake of example a 200 mW 23 dBm amplifier deigned to perform with a 25 dB MER will use as final stage a device which has a P1 dB around...

Page 15: ...l Communications and Surveillance www cobham com tcs CAUTION WHEN COMBINING A TRANSMITTER WITH A PA FOR THE FIRST TIME THE CUSTOMER SHOULD ALWAYS MAKE SURE THAT THE POWER OUTPUT OF THE TRANMITTER IS C...

Page 16: ...he VEPA 2W frequency bands The PA has repeatable performances from unit to unit 6 1 GAIN 2W COFDM Output Figure 4 LD Band Gain Figure 5 LD Band Gain Change over Temp Figure 6 L2 Band Gain Figure 7 L2...

Page 17: ...100 M0167X2 17 of 21 GMS Inc doing business as Cobham Tactical Communications and Surveillance www cobham com tcs Figure 14 C2 Band Gain Figure 15 C2 Band Gain Change over Temp...

Page 18: ...m Tactical Communications and Surveillance www cobham com tcs 6 2 Current 2W COFDM Output 12 Vdc Figure 16 LD Band Current Figure 17 L2 Band Current Figure 18 W7 Band Current Figure 19 S2 Band Current...

Page 19: ...business as Cobham Tactical Communications and Surveillance www cobham com tcs 6 3 MER 2W COFDM Output Figure 22 LD Band MER Figure 23 L2 Band MER Figure 24 W7 Band MER Figure 25 S2 Band MER Figure 26...

Page 20: ...ns and Surveillance www cobham com tcs 6 4 Small Signal S Parameter High Efficiency Mode Figure 28 LD Band S Parameters Figure 29 L2 Band S Parameters Figure 30 W7 Band S Parameters Figure 31 S2 Band...

Page 21: ...n GMS Global Microwave Systems LO Local Oscillator M2T Messenger 2 Transmitter MER Modulation Error Ratio M2Te Messenger 2 Enhanced Transmitter PA Power Amplifier PAR Peak Average Ratio PWR Power QAM...