User manual RAMSEY QAMP20

[. . . ] 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! QAMP20 · 1 RAMSEY TRANSMITTER KITS · FM10A, FM25B FM Stereo Transmitters · TV6 Television Transmitter · Cube TV Transmitters RAMSEY RECEIVER KITS · FR1 FM Broadcast Receiver · AR1 Aircraft Band Receiver · SR2 Shortwave Receiver · AA7 Active Antenna · SC1 Shortwave Converter RAMSEY HOBBY KITS · SG7 Personal Speed Radar · SS70A Speech Scrambler · TT1 Telephone Recorder · SP1 Speakerphone · MD3 Microwave Motion Detector · PH10 Peak hold Meter · LC1 Inductance-Capacitance Meter RAMSEY 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 other kits are available for hobby, school, Scouts and just plain FUN. Write or call for our free Ramsey catalog. QAMP20 QRP CW POWER AMPLIFIER KIT INSTRUCTION MANUAL Ramsey Electronics publication No. [. . . ] QRP transmitter with a power output in the ½ to 2 watt range, such as the Ramsey QRP-20. Proper cables to interface between the QRP transmitter and the QRP power amplifier. Connect a multimeter to TP1; set the meter to read up to 5 volts DC 3. In a pinch, a light bulb may be used - see the section, "Verifying RF Power Output. " QAMP20 · 12 4. Measure the current drawn by the amplifier and slowly rotate the bias pot, R4, clockwise until you reach a reading of ¼ amp. If you cannot adjust or reduce the current, disconnect the power supply and consult the troubleshooting hints section. Measure the DC current draw; it should be in the 1 to 3 amp range depending upon power output. The relay should drop out and the current should drop back down to ¼ amp. 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. Study the following sections on DC power supply and RF power considerations. 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. For example, two lantern batteries in series, or 8 D cells, will obviously provide about 12 volts with sufficient current capability for casual operating. The easiest method is to place two fresh D cells in series with your power source if a full 13. 6 - 15 volts DC is not available. Be aware that batteries are not the optimum power source, especially if you are prone to long QSOs!A word of caution concerning wall plug style AC adapter power supplies: They are not suitable for operation of your amplifier due to their poor regulation, AC ripple content, and RFI susceptibility. With 1 watt of drive and a supply voltage in the 11-12 volt range, you can expect a 1 to 2 amp current draw and about 10 watts of RF output power. With a solid 13 to 14 volt supply, you can expect about 2 to 3 amps current draw and up to 10 or 12 watts of RF output power. 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. QAMP20 · 13 Ideally, you have a small RF wattmeter, already inserted in the antenna line, capable of accurately measuring low output power in watts. 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 need help, please read through your manual carefully, all information required to properly build and test your kit is contained within the pages!DEFECTIVE PARTS: It's always easy to blame a part for a problem in your kit, Before you conclude that a part may be bad, thoroughly check your work. Today's semiconductors and passive components have reached incredibly high reliability levels, and it's sad to say that our human construction skills have not!All our kit parts carry the Ramsey Electronics Warranty that they are free from defects for a full ninety (90) days from the date of purchase. [. . . ]