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QAMP20 • 12
50. Install L2, the 14 turn toroid inductor - you marked it special,
remember?
51. Install L3, the remaining 12 turn toroid inductor.
This completes the assembly of your QRP power amplifier. Now's a good time to
give your masterpiece a good going over, being especially alert for any:
• bridged-over 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. 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 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.
With the above all set up and handy, let's get testing!
1. Rotate Bias pot R4 fully CCW.
2. Connect a multimeter to TP1; set the meter to read up to 5 volts DC
3. Connect a dummy load to J1, the amplifier RF output. In a pinch, a light bulb
may be used - see the section, "Verifying RF Power Output."