DANIELS TM ELECTRONICS LTD. MT-3 RADIO SYSTEMS VT-3A130 AMPLIFIER INSTRUCTION MANUAL 118 - 138 MHz Covers the following: Amplifier portion of VT-3A130-SYD410 Copyright © 2000 Daniels Electronics Ltd. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, without the prior written consent of Daniels Electronics Ltd.
Reviewed By: Quality Assurance: Claudia Boorman Name Signature _________________ Date NOTE: The user's authority to operate this equipment could be revoked through any changes or modifications not expressly approved by Daniels Electronics Ltd. The design of this equipment is subject to change due to continuous development. This equipment may incorporate minor changes in detail from the information contained in this manual.
TABLE OF CONTENTS Page 1 GENERAL................................................................................. 1-1 1.1 Introduction .......................................................................... 1-1 1.2 Performance Specification.......................................................... 1-1 2 THEORY OF OPERATION............................................................. 2-1 2.1 General ............................................................................... 2-1 2.
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1 GENERAL 1.1 Introduction The VT-3A130 Amplifier provides the final stage of RF amplification and filtering for the VT-3A Transmitters. The output power is 1.0 - 4.0 Watt adjustable (carrier only). The amplifier operates over 118MHz - 138 MHz frequency range without tuning. Output filtering for the VT-3A130 Amplifier is provided by an Output Lowpass Filter Board.
Amplifier Enable: Active to ground. Output Power Rise Time (10-90% of steady state value) Less than 20 ms Output Power Fall Time (90-10% of Steady state value) Less than 10ms Key-On/Key-off Spectral Mask Transients are at least 80 dBc for frequencies ± 400 kHz from carrier. Operating Temperature Range: -30˚C to +60˚C, optional - 40˚C temperature test.
2 2.1 THEORY OF OPERATION General VT-3A130 Amplifier is a Class A linear amplifier with a low level AM modulator. A built in regulated power supply provides approximately 15.0Vdc output voltage with the input voltage range of 10.0 Vdc to 17 Vdc. This amplifier utilizes a 10 Watt hybrid power amplifier module manufactured by Mitsubishi. The module is mounted directly to the heatsink with its leads soldered to a circuit board where DC supply voltage and RF input and output connections are made.
The part of the output RF energy is coupled by a directional detector circuit TL1 which provides a means of linearization of the audio and leveling of the output power over the frequency range 118 MHz to 138 MHz. The AC coupled audio signal is applied to the inverting input of U4a in order to provide predistortions to the input modulation audio signal, which is supplied from the audio amplifier U2 to the non-inverting input of U4a.
3 3.1 VT-3A130 AMPLIFIER ALIGNMENT General Connections to the power supply, audio input and transmit enable line are clearly marked on the amplifier case. The amplifier is enabled when the enable line (AMPLIFIER ENABLE pin) is grounded. If the amplifier is installed in the transmitter, alignment is simplified by using the SR-3 Subrack, SM-3 System Monitor, and RF extender cable to provide transmitter power and signal interconnection (see the Transmitter Main Board Manual for details).
3.4 Recommended Test Equipment List Alignment of the transmitter requires the following test equipment or its equivalent. Dual Power Supply: Oscilloscope / Multimeter: Current Meter: Radio communications test set: VSWR 3:1 mismatch load: Alignment Tool: 3.5 Regulated +9.5 Vdc at 0.1 A. Regulated +13.8 Vdc at 2 A - Topward TPS-4000 Fluke 97 Scopemeter Fluke 75 multimeter Marconi Instruments 2955R JFW 50T-035-3.0:1 Johanson 8766 VT-3A130 Amplifier Alignment 3.5.
9. Apply a 1000 Hz signal with 0.200 Vrms level to the amplifier's MODULATION INPUT and adjust AUDIO ADJUST pot R35 to obtain 90% of AM modulation. 10. Adjust the DISTORTION ADJUST pot R14 to the lowest distortion (less than 5%) 11. Change the RF signal frequency to 128 MHz, 138 MHz and control the Modulation Level and Output Power (with no modulation). 12. Re-adjust the AUDIO ADJUST pot R35 (if it necessarily) so that the modulation level do not exceed 90% at 128 MHz and 138 MHz frequencies. 13.
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4 4.
4.1.1 VT-3A130 Amplifier Component Layout TP3 C35 220µH U1 M68721 C41 220µH C39 100nF R46 332R R45 3k74 TP1 C12 100nF C2 D2 100nF C1 R39 SR502 C33 220µH R7 R10 47R5 100nF R8 22R1 C11 1k82 100nF 332R C3 C13 Q1 100nF R37 R38 100nF L1 D1 22R1 22R1 NE02139 R9 1.5µH MMBD701 Q3 3k01 NE02139 R1 C6 R5 1k82 R31 3k01 150pF TP2 R2 100R Q4 R29 3k01 NE02139 R34 R30 10k L3 C25 56k2 10k0 C34 TL1 R33 1.5µH 100nF 1µF 2k21 C19 R26 C18 4.
4.1.2 VT-3A130 Amplifier Schematic Diagram TO ALL 9.5V SUPPLY POINTS FIL1 LOW PASS FILTER Q2 VP0610T RFC1 5500PF U1 M68721 S 1 D TL1 0.5" COAX 9.5Vdc C10 47uF C20 47uF C9 47uF G 1 C14 10nF 3 RF IN 118-138 MHz RF OUT 4 2 4 AMPLIFIER ENABLE 5 2 1 2 2 3 D1 MMBD701 XFMR1 TTWB-4-B RFC2 5500PF 1 4 1 1 R32 1K00 J2 SMA 3 R4 100R0 6 1 R2 3K01 C11 100nF R7 22R1 R8 332R0 15V 8dB Att.
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4.2 VT-3A130 Lowpass Filter 4.2.1 VT-3A130 Lowpass Filter Component Layout C4 30pF L2 C2 7.5pF L1 C6 24pF L3 C1 15pF C5 4.7pF C3 30pF PCB 50086-01 VT3A130AMPM3A 4.2.2 VT-3A130 Lowpass Filter Schematic Diagram L1 3.0 TURNS RF INPUT L3 3.0 TURNS RF OUTPUT L2 4.0 TURNS C5 4.7pF C1 15pF C2 7.5pF C3 30pF C4 30pF C6 24pF HIGHEST REFERENCE DESIGNATORS C6 L3 ----- ----- ----- ----- ----- ----- ----- UNUSED REFERENCE DESIGNATORS DANIELS VICTORIA B.C. ELECTRONICS LTD.
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5 PARTS LISTS 5.1 VT-3A130 Amplifier Electrical Parts List Ref Design Description Part No. C1 C2, C3 C4 C5 C6 C7, C8 C9, C10 C11 – C13 C14 C15 C16 C17 C18 C19 C20 C21 – C25 C26 C27 C28, C29 C30 C31 C32 C33 C34 C35 C36 C37 – C39 C40 C41 CAP., 220uF ELECTRO.,AXIAL,25V CAP., SM, 100nF CER., 0805, X7R, 50V CAP., SM, 10nF CER,0805,X7R,50V CAP., SM, 100nF CER., 0805, X7R, 50V CAP., SM, 150pF CER., 0805,C0G CAP., SM, 100nF CER., 0805, X7R, 50V CAP., SM, 47uF TANT., 20%, 16V CAP., SM, 100nF CER.
Ref Design Description RFC1 RFC2 RFC3 RFC4 FILTER, FILTER, FILTER, FILTER, R1 R2 R3 R4 R5 R7 R8 R9 R10 R11 R12 R13 R14 R15 R16 R17, R18 R19 R20 R21 R22 R23 R24 R25 R26 R27 R28 R29 R30 R31 R32 R33 R34 R35 R36 R37, R38 R39 R40 R41 R42 R43 R44 R45 R46 R47 RES., SM, 1K82 0805, 1%,100ppm RES., SM, 3K01 0805, 1%,100ppm RES., SM, 75K0 0805, 1%,100ppm RES., SM, 100R0 0805, 1%,100ppm RES., SM, 3K01 0805, 1%,100ppm RES., SM, 22R1 1206, 1%,100ppm RES., SM, 332R0 0805, 1%,100ppm RES., SM, 3K01 0805, 1%,100ppm RES.
Ref Design Description Part No. U1 U2 U3 U4 U5 U6 AMP, RF,M68721,10W,118-137 MHz IC, LM386 LV AUDIO AMP.,SO-8 IC, LM2588,REG./ADJ,FLBK,T0263 IC, MC33172 DUAL OP AMP, SO-8 IC, LM1084IT,REG./ADJ,5A,T0220 IC, MC33172 DUAL OP AMP, SO-8 2256-M6872100 2323-386M1N08 2305-25880263 2302-33172N08 2205-10842203 2302-33172N08 XFMR1 TRANSFMR,RF/WB,.
5.2 VT-3A130 Lowpass Filter Electrical Parts List Ref Desig Description C1 C2 C3, C4 C5 C6 CAP., CAP., CAP., CAP., CAP., 15pF PORCEL.,+-5%500V 7.5pF PORCEL.,+-.25pF 30pF PORCEL., 5%,500V 4.7pF PORCEL.,+-.25pF 24pF PORCEL., 5%,500V 1036-1B2150J5 1036-0B2759C5 1036-1B2300J5 1036-0B2479C5 1036-1B2240J5 PCB PCB, LPF,TX AMP,AM VT-3A130-10 4322-16500861 L1 L2 L3 COIL, 3 TURNS,18AWG,6.35 mm ID COIL, 4 TURNS,18ANG,6.35 mm ID COIL, 3 TURNS,18AWG,6.35 mm ID 1220-3T001622 1220-4T001622 1220-3T001622 5.
6 REVISION HISTORY ISSUE DATE DESCRIPTION AND (REASON) 1 May 97 • First Issue. 2 Mar 98 • To improve the performance at -40˚C. ECO #546. C35 was 2.2µF now not installed. R19 was 274R now not installed. R20 was 274R now not installed. R21 was 18R2 now 0R00. PCB was 50048-01 now 50048-02. 3 Mar 98 • Updated the PCB to make it easier to assemble. ECO #551. PCB was 50048-02 now 50048-03. 4 Mar 00 • Corrected the instruction manual part number on the title page.
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