Ramsey Electronics QAMP20, User Manual

Page 1: ...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 Operat...

Page 2: ...r 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 other kits are available for hobby school Scouts a...

Page 3: ...ctions 7 Initial tests 12 Verifying RF output power 13 Troubleshooting tips 15 Using the QAMP20 16 Parts layout diagram 17 Schematic diagram 18 Ramsey kit warranty 19 KIT ASSEMBLY AND INSTRUCTION MANU...

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: ...70 ohm resistors red violet brown R8 9 1 51 ohm resistor green brown black R10 1 2 2 K ohm resistor red red red R11 1 5 K potentiometer marked 502M R4 SEMICONDUCTOR DEVICES 1 Zener diode 6 2 volt gray...

Page 6: ...the problems we find here at the factory are due to faulty assembly no matter how experienced the builder may be it s especially tough to tell a 30 year experienced ham that he goofed Before you run...

Page 7: ...RCA phono jacks Solder all 4 pins on each securely as these connectors will be subjected to some stress when coax cables are connected to them 3 Install J3 PC mount DC power jack 4 Install relay K1 N...

Page 8: ...or proper operation Generally capacitors have their 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 pr...

Page 9: ...nother 180 f disc capacitor marked 180 or 181 38 Install wire jumper JMP1 Use a scrap piece of component lead wire 39 Locate the MOSFET power transistors and prepare the leads for insertion into the P...

Page 10: ...t or a magic marker We don t want to confuse it with the other two toroid coils wound just before 43 Winding T2 Locate the smaller of the two 2 hole ferrite cores Cut off one 11 inch length of enamele...

Page 11: ...le 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 46 Cut off another length of wire 9 inches long Wind 1 turn through the...

Page 12: ...for testing you ll need the following 1 Multimeter capable of measuring voltage and current 2 12 volt DC power source of at least 3 amp capacity 3 Suitable dummy load and resonant antenna 4 QRP trans...

Page 13: ...r transmitter with good amateur practice YOUR POWER SUPPLY AND RF OUTPUT POWER For optimum performance one or two volts of extra DC supply power can make quite a difference in any RF power amplifier F...

Page 14: ...m 2 to 25 volts RMS depending on various factors Typically 1 watt power levels are achieved in the 5 to 7 volts RMS range 5 watts at 12 to 15 volts and 10 watts at 20 to 25 volts A good test bulb for...

Page 15: ...e for this occurring Any prolonged parasitic emissions may also overheat and destroy other components in the amplifier TROUBLESHOOTING HINTS The QRP power amplifier is very straight forward and simple...

Page 16: ...r QRP operation and an amplifier is not a band aid for a poor antenna system For maximum performance a QRP station must include the following 1 A resonant antenna dipole or quarter wave vertical 2 Goo...

Page 17: ...small homemade keyer etc The controls are easily mounted at one end of such a box It may be necessary to cut away the molded posts which secure the tape itself These storage boxes come in several styl...

Page 18: ...QAMP20 18...

Page 19: ...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 20: ...LIFIER KIT This Quality Electronics Kit was designed and packed in the USA REQUIRED TOOLS Soldering Iron Ramsey WLC100 Thin Rosin Core Solder Ramsey RTS12 Needle Nose Pliers Ramsey MPP4 or RTS05 Small...