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30 MTR 20 WATT QRP
LINEAR AMPLIFIER KIT
Ramsey Electronics Model No.
Need a little extra boost for your QRP rig? Believe it or not, 20 watts is only
about an 'S' unit below a 100 watt rig! This nifty little amp will add some
"punch" to any QRP transmitter.
•
Works great with Ramsey QRP rigs or any other 1-2 watt
transmitters
•
Built-in T/R relay automatically switches between receive and
transmit
•
Runs on 12 volts DC at 2 to 4 amps; ideal for field day or battery
operation
•
Multistage low pass filter for a clean signal
•
Operates all modes: CW, SSB, or AM
•
Fast, easy, and fun 2 hour assembly
•
Informative manual answers questions on theory, hook-ups, and
uses - enhances resale value too!
•
Clear, concise assembly instructions carefully guide you to a
finished kit that works the FIRST time!
QAMP-30 • 1
QAMP30
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Related Manuals for Ramsey Electronics QRP CW POWER AMPLIFIER KIT QAMP30
Summary of Contents for Ramsey Electronics QRP CW POWER AMPLIFIER KIT QAMP30
- Page 1 30 MTR 20 WATT QRP LINEAR AMPLIFIER KIT Ramsey Electronics Model No. Need a little extra boost for your QRP rig? Believe it or not, 20 watts is only about an ‘S’ unit below a 100 watt rig! This nifty little amp will add some “punch”...
- Page 2 1994 by Ramsey Electronics, Inc. 590 Fishers Station Drive, Victor, New York 14564. All rights reserved. No portion of this publication may be copied or duplicated without the written permission of Ramsey Electronics, Inc. Printed in the United States of America. First printing: January 1993...
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Page 3: Table Of Contents
Parts layout diagram ... 17 Schematic diagram ... 18 Ramsey kit warranty ... 19 QAMP-30 • 3 Ramsey Publication No. MQAMP30 KIT ASSEMBLY RAMSEY ELECTRONICS, INC. 590 Fishers Station Drive Victor, New York 14564 Phone (585) 924-4560 Fax (585) 924-4555 www.ramseykits.com... -
Page 4: How It Works
INTRODUCTION The Ramsey QAMP series of QRP power amplifiers are compact 10 to 20 watt RF amplifiers for QRP CW transmitters. These amplifiers are made to be driven by transmitters in the ½ to 2 watt range. Built-in to the power amplifier is a sensitive T-R relay which will switch the unit in and out of the antenna line. -
Page 5: Parts List
PARTS LIST FOR THE QAMP30 QRP POWER AMPLIFIER CAPACITORS: 100 to 220 µf electrolytic capacitor [C1] 10 µf electrolytic capacitor [C2] .1 µf disc capacitor (marked .1 or 104) [C3,8,10,13] 330 ρf disc capacitor (marked 330 or 331) [C4,7] 560 ρf disc capacitor (marked 560 or 561) [C5,6] .001 µf disc capacitor (marked .001 or 102 or 1000) [C11,12] .01 µf disc capacitor (marked .01 or 103 or 10 nf) [C9] RESISTORS:... -
Page 6: Tips And Notes
"THE RAMSEY LEARN-AS-YOU-BUILD ASSEMBLY STRATEGY" Take a look at the parts layout diagram. There is quite a lot to the construction of the QAMP30. It's easier than it seems once you get going, especially after you have installed a few of the "landmark" components. Once these "landmark"... - Page 7 • If helpful, gently bend the part’s wire leads or tabs to hold it in place, with the body of the part snugly against the top side (component side) of the PC board. • Solder all wires or pins of the part, whether the 2 wires of a resistor or the 3 or 4 wires of a transistor.
- Page 8 16. Install diode D4, 1N4002 style black epoxy diode. Check positioning of the banded end. 17. Install jumper JMP2. Use a piece of scrap component lead wire bent into a "staple" shape and inserted into the board like a component. Jumpers act as electronic "bridges"...
- Page 9 These last four parts (R8,9 and C11,12) form parasitic suppression networks across each transistor to suppress any tendency for high frequency oscillation in the power amplifier. 32. Install C3, another .1 µf disc capacitor (marked .1 or 104). Both of these capacitors bypass the center tap of the ferrite transformers to ground.
- Page 10 We're almost finished. All we need to do now is install a few remaining parts that have to be handmade - for that "old-world craftsmanship" touch! We'll prepare all those parts now for further assembly. We give you plenty of enameled wire, but if you mess up, you can get a whole 50' spool of it from Radio Shack.
- Page 11 amount of wire cut for this task is the proper amount. If you have too little or too much, then you have not wound the core correctly. Tin each end with solder as before. Tin all the way up to the core body. This winding is the primary of transformer T2.
- Page 12 Secondary leads (wound previously) 1 turn with loop then 47. Locate the smaller transformer (T2) and install it snugly on the PC board. 48. Install the larger transformer (T1) into the indicated location on the PC board. 49. Install L1, a 15 turn toroid inductor wound previously. If desired, a small dab of hot melt glue, bathtub sealer, or caulk may be used to secure the toroids.
- Page 13 3. Connect a dummy load to J1, the amplifier RF output. In a pinch, a light bulb may be used - see the section, "Verifying RF Power Output." 4. Temporarily install a jumper from the collector of Q3 to ground. 5.
- Page 14 VERIFYING TRANSMITTER RF OUTPUT The most important thing to know is whether your transmitter is delivering some measurable and reassuring level of RF power. Then you can continue on to adding the QRP amplifier and checking out the whole set-up. Ideally, you have a small RF wattmeter, already inserted in the antenna line, capable of accurately measuring low output power in watts.
- Page 15 Amateur radio magazines and handbooks provide a variety of circuits for RF wattmeters and relative field-strength indicators, including methods of using your VOM as an indicating device. CQ magazine for March 1990 offers an article by KB4ZGC on how to make a highly accurate yet inexpensive dummy load and wattmeter capable of showing 1/10-watt differences in RF power.
- Page 16 If you hear an AC hum on the transmitted signal, usual causes are RF getting back into the power supply or a bad VSWR on the antenna. These short checks in no way detail any and all problems that can rear their ugly head, but should get you on the way to solving most errors.
- Page 17 While we believe that the Ramsey enclosure and knob option is a fine value for finishing off your Ramsey kit, we are happy to give you a couple of additional suggestions and our reasons for them. If your first goal is economy and rugged portability, you will find that the circuit board can be mounted nicely in a standard VHS videotape storage box, which also gives room for storing cables, a small homemade keyer, etc.
- Page 18 QAMP-30 • 18...
- Page 19 'missing' 10 K parts ("Hum-m-m, I guess the 'red' band really does look orange!") Ramsey Electronics project kits are packed with pride in the USA. If you believe we packed an incorrect part or omitted a part clearly indicated in your assembly manual as supplied with the basic kit by Ramsey, please write or call us with information on the part you need and proof of kit purchase.
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Page 20: Initial Testing
• Digital Multimeter Ramsey M133 Price: $5.00 Ramsey Publication No. MQAMP30 Assembly and Instruction manual for: RAMSEY MODEL NO. QAMP30 30 METER 20 WATT RAMSEY ELECTRONICS, INC. 590 Fishers Station Drive Victor, New York 14564 Phone (585) 924-4560 (585) 924-4555 www.ramseykits.com...