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QAMP-40 • 1 

Ramsey Electronics Model No.     QAMP40 

 

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! 

 
 

40 MTR 20 WATT QRP 
LINEAR AMPLIFIER KIT 

Summary of Contents for QAMP40

Page 1: ...s 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 Opera...

Page 2: ...ion Detector ML Music Lights Kit LC1 Inductance Capacitance Meter RAMSEY AMATEUR RADIO KITS HR Series HF All Mode Receivers QRP Series HF CW Transmitters CW7 CW Keyer QRP Power Amplifiers RAMSEY MINI...

Page 3: ...tions 6 Initial testing 12 Verifying RF output power 13 Troubleshooting tips 15 Using the QAMP40 16 Parts layout diagram 17 Schematic diagram 18 Ramsey kit warranty 19 KIT ASSEMBLY AND INSTRUCTION MAN...

Page 4: ...P amplifier is very simple with most of the magic being done by just a few parts the pair of MOSFET transistors and the ferrite wideband transformers Transformer T2 matches the 50 ohm amplifier input...

Page 5: ...d red R11 1 5 K potentiometer marked 502M R4 SEMICONDUCTOR DEVICES 1 Zener diode 6 2 volt gray body with black band D1 2 1N4148 type signal diode glass body with black band D2 3 1 1N4002 style black e...

Page 6: ...d polarized capacitors for proper orientation TIPS AND NOTES Use a good soldering technique let your soldering iron tip gently heat the traces to which you are soldering Heat both wires and pads simul...

Page 7: ...ls only one way 5 Install potentiometer R4 This pot allows adjustment of the bias to the power transistors 6 Install C9 01 f disc capacitor marked 01 or 103 or 10 nf 7 Install Q5 221334 PNP transistor...

Page 8: ...lead marked with a black stripe while PC boards have the hole indicated 22 Install D1 6 2 volt Zener diode gray body with a black band This diode provides a stable voltage which is used to provide bia...

Page 9: ...Be sure to observe correct polarity 34 Install C4 560 f disc capacitor marked 560 or 561 35 Install C5 330 f disc capacitor marked 330 or 331 36 Install C6 another 330 f disc capacitor marked 330 or 3...

Page 10: ...older Tin all the way up to the toroid core body 42 Winding L2 Locate the remaining yellow toroid core and cut 15 of the enameled magnet wire Wind 22 turns through the core using the same procedure as...

Page 11: ...mplete turns through the core Again the 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...

Page 12: ...er solder joints misplaced components transistors or diodes placed wrong electrolytic capacitors installed wrong INITIAL TESTS To prepare your amplifier for testing you ll need the following 1 Multime...

Page 13: ...e Ramsey CQAMP case set provides an ideal perfectly sized cabinet that matches all other Ramsey kits Study the following sections on DC power supply and RF power considerations Operate your transmitte...

Page 14: ...a socket for the bulb of your choice or even soldered directly to the bulb RF voltage levels in this amplifier can vary from 2 to 25 volts RMS depending on various factors Typically 1 watt power level...

Page 15: ...in the neighborhood A poorly matched antenna along with higher supply voltages is usually responsible for this occurring Any prolonged parasitic emissions may also overheat and destroy other component...

Page 16: ...al USING THE QRP POWER AMPLIFIER Hooking up and using the amplifier is easy Just connect your existing transmitter to the QAMP input and the antenna to the QAMP output A resonant antenna is an absolut...

Page 17: ...rcuit board can be mounted nicely in a standard VHS videotape storage box which also gives room for storing cables a small homemade keyer etc The controls are easily mounted at one end of such a box I...

Page 18: ...QAMP 40 18...

Page 19: ...ch be assured that the 1K ohm resistors are actually the 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...

Page 20: ...al for RAMSEY MODEL NO QAMP40 40 METER 20 WATT LINEAR AMPLIFIER KIT RAMSEY ELECTRONICS INC 590 Fishers Station Drive Victor New York 14564 Phone 585 924 4560 Fax 585 924 4555 www ramseykits com REQUIR...

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