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QRP-20 

 1  

20 METER   (14MHz) 
CW TRANSMITTER 

Ramsey Electronics Model No.           QRP20 

THE RAMSEY QRP20 IS AN AMAZING PERFORMER 
THAT WILL WORK THE WORLD ON ABOUT A WATT! 
FOLKS OF ALL AGES HAVE SUCCESSFULLY BUILT  
AND ENJOYED THIS EASY,  FUN KIT. 

Ideal for portable or travel fun 

VCXO design allows up to 8 - 10 KHz of tuning about the crystal 
frequency 

Front panel switching of TWO channels and includes a crystal for 
14.06 MHz, the International QRP frequency  

Excellent and clean keying waveform 

Built-in antenna T-R switch 

Operates on 12 - 15 volts DC at 1/4 amp current 

Appoximately 1 Watt RF power 

Clear, concise step-by-step instructions carefully guide you to a 
finished kit that not only works - but you’ll also learn too! 

Proven design that has won many of awards for operators around 
the country! 

Add our case and knob set for a finished ‘Pro’ look. Cases match all 
Ramsey products 

Summary of Contents for QRP20

Page 1: ...cy Front panel switching of TWO channels and includes a crystal for 14 06 MHz the International QRP frequency Excellent and clean keying waveform Built in antenna T R switch Operates on 12 15 volts DC...

Page 2: ...EY AMATEUR RADIO KITS DDF1 Doppler Direction Finder HR Series HF All Mode Receivers QRP Series HF CW Transmitters CW7 CW Keyer CPO3 Code Practice Oscillator QRP Power Amplifiers RAMSEY MINI KITS Many...

Page 3: ...ram 10 Parts Layout Diagram 11 QRP20 Assembly Instructions 12 Crystal Oscillator Testing 16 Initial Tests 17 Verifying RF Power 18 Maximizing RF Power Output 19 Options for Finishing Project 20 Enclos...

Page 4: ...er amplifier or switching from 25 to 5 watts on your new Radio Shack 10 meter rig or turning back the carrier level control on most modern transceivers For equipment description and contest competitio...

Page 5: ...utput power received from a transmitter 2 Power needs to be increased four times or 400 to result in a true 1 S unit or 6db RST gain 3 Reducing output power down to 25 of previous power should result...

Page 6: ...same path S9 20db 1000 watts S9 10db 100 watts S9 10 watts S8 2 5 watts S7 625 watts S6 156 watt S5 039 watt S4 0087 watt Under reasonably good band conditions particularly at 10 or 14 MHz and on up...

Page 7: ...is almost one million times more powerful than the transmitter used in that historic test WHO SHOULD USE A QRP TRANSMITTER There is a philosophy that Novices should not get started with a very low pow...

Page 8: ...positive bias to the base of Q2 through R8 and 12VDC through choke L4 to the anode of D1 which permits RF to pass through D1 to the filter network while applying negative bias to D2 which blocks RF fr...

Page 9: ...violet brown R10 1 470 ohms yellow violet brown R6 2 1K ohms brown black red R12 13 4 10K ohms brown black orange R4 5 14 15 1 47K ohms yellow violet orange R8 2 1 megohm brown black green R2 3 1 10K...

Page 10: ...QRP 20 10...

Page 11: ...QRP 20 11 QRP20 PARTS LAYOUT DIAGRAM...

Page 12: ...ed some familiarity with general electronics practices and language Therefore you can expect the following procedures to move along with less of the hand holding which we offer for our receivers and o...

Page 13: ...er during transmission and permits the antenna to be connected to the receiver jack during key up conditions To further complete this section of the circuit we now install the first of three 100 uh RF...

Page 14: ...ing frequency S1 permits your choice of any two installed crystals the one that comes with your kit and another which you may add on your own If you plan to add a socket for your own crystal it should...

Page 15: ...re hookups as soon as they are completed This is most especially true with low power transmitters To try out this transmitter you will need the following and we ll offer suggestions about each of them...

Page 16: ...of emitting an RF signal and HARMONICS when and if connected to an antenna It is correct practice to keep your test brief and to identify them with your callsign FURTHER ASSEMBLY The following three...

Page 17: ...ck your connections or have a friend go over them Give extra attention to the work associated with Q2 and Q3 It s always easier to catch an error now before final testing Easier on the cicuit parts an...

Page 18: ...this solid state transmitter does not require tuning or adjustments a periodic power output check up should suffice If you do not own or have access to a low level RF power meter use a trick that is d...

Page 19: ...um reasonable power output without component damage is to run the DC voltage in the 14 to 15 volt range observing a maximum limit of 18VDC IMPORTANT NOTE If you are experimenting with this transmitter...

Page 20: ...iver or transmitter 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 b...

Page 21: ...device The whole idea of this transmitter is to keep things simple and economical so we cannot overemphasize the priority of a clean efficient connection of the transmitter output to a resonant anten...

Page 22: ...QRP 20 22...

Page 23: ...h 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 24: ...anual for RAMSEY MODEL NO QRP20 20 METER CW TRANSMITTER KIT REQUIRED TOOLS Soldering Iron Ramsey WLC100 Thin Rosin Core Solder Ramsey RTS12 Needle Nose Pliers Ramsey MPP4 or RTS05 Small Diagonal Cutte...

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