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20 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!
Downloaded by
RadioAmateur.EU
QAMP20 • 1
QAMP20
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Summary of Contents for Ramsey Electronics QAMP20
- Page 1 ‘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 •...
- Page 2 RAMSEY MINI-KITS Many other kits are available for hobby, school, Scouts and just plain FUN. New kits are always under development. Write or call for our free Ramsey catalog. QAMP20 QRP CW POWER AMPLIFIER KIT INSTRUCTION MANUAL Ramsey Electronics publication No. MQAMP20 Revision 1.5a First printing: January 1993 ...
- Page 3 AND INSTRUCTION MANUAL FOR 20 METER QRP CW POWER AMPLIFIER KIT TABLE OF CONTENTS Introduction to the QAMP20 ... 4 How it works ........4 Parts list ......... 5 Learn as you Build ......6 QAMP20 assembly instructions ..7 Initial tests ..
- Page 4 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 FOR THE QAMP20 QRP POWER AMPLIFIER CAPACITORS: 1 100 to 220 µf electrolytic capacitor [C1] 1 10 µf electrolytic capacitor [C2] 4 .1 µf disc capacitors (marked .1 or 104) [C3,8,10,13] 2 180 ρf disc capacitors (marked 180 or 181) [C4,7] 330 ρf disc capacitors (marked 330 or 331) [C5,6]...
- Page 6 Take a look at the parts layout diagram. There is quite a lot to the construction of the QAMP20. 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 Both diode D3 and diode D2 are detectors for sensing applied RF power. 13. Install C10, .1 µf disc capacitor (marked .1 or 104). 14. Install R7, 100 K ohm resistor (brown-black-yellow). QAMP20 • 7...
- Page 8 28. Install C11, .001 µf disc capacitor (marked .001 or 102). 29. Install R9, another 270 ohm resistor (red-violet-brown). 30. Install C12, another .001 µf disc capacitor (marked .001 or 102). 31. Install C8, .1 µf disc capacitor (marked .1 or 104). QAMP20 • 8...
- Page 9 - for that "old-world craftsmanship" touch! We'll prepare all those parts now for further assembly. We supplied plenty of enameled wire for your kit but if you mess up, you can get a whole 50' spool of it from Radio Shack (278-1341). QAMP20 • 9...
- Page 10 44. Cut off another length of the same wire, 8 inches long. Wind 1 turn through the core, loop out 1 inch, twist together and run one more turn 14 turns through center of core IMPORTANT: Loop the first winding around the front of the core as shown. QAMP20 • 10...
- Page 11 48. Install the larger transformer (T1) into the indicated location on the PC board. 49. Install L1, a 12 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. QAMP20 • 11...
- Page 12 3. Suitable dummy load and resonant antenna. • 4. QRP transmitter with a power output in the ½ to 2 watt range, such as the Ramsey QRP-20. • 5. Proper cables to interface between the QRP transmitter and the QRP power amplifier.
- Page 13 This completes the testing of your QRP power amplifier. The PC board should be mounted into a protective enclosure to guard against accidental contact. The Ramsey CQAMP case set provides an ideal perfectly sized cabinet that matches all other Ramsey kits.
- Page 14 Saying the same thing another way, we assume you know that accurate, commercially built RF wattmeters cost much more than what you paid for this Ramsey amplifier kit. Since this solid-state amplifier does not require lots of critical tuning or adjustments, a periodic power output check-up should suffice. If you don’t own or have access to a low-level RF power meter, use a trick that is...
- Page 15 RF path through the relay. The amplifier should draw about ¼ amp with no signal applied. If you see more than that, recheck the bias setting (see the section "INITIAL TESTS"). QAMP20 • 15...
- Page 16 You might be planning to combine several Ramsey circuit kit boards in a single enclosure. Use of the inexpensive and attractive Ramsey case and hardware set will give your unit that nice finished look and increase its resale value.
- 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...
- Page 18 QAMP20 • 18...
- Page 19 Notice that this is not a "fine print" warranty. We want you to understand your rights and ours too! All Ramsey kits will work if assembled properly. The very fact that your kit includes this new manual is your assurance that a team of knowledgeable people have field-tested several "copies" of this kit straight from the Ramsey Inventory.
- Page 20 Digital Multimeter Ramsey M133 Downloaded by RadioAmateur.EU Price: $5.00 Ramsey Publication No. MQAMP20 Assembly and Instruction manual for: RAMSEY MODEL NO. QAMP20 20 METER 20 WATT LINEAR AMPLIFIER KIT RAMSEY ELECTRONICS, INC. 590 Fishers Station Drive Victor, New York 14564 This Quality Electronics...
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