Half Pint QRP transciever

by W. Rossi, KA1QYP

Prototype of the Half Pint built in a small cookie tin.

The "Half Pint" is a easy to build QRP transciever, built with just 7 transistors. I've had quite a bit of fun building and operating this little rig. I hope you will enjoy it as much as I have.

It features a direct conversion receiver with an active audio filter.

Specifications

• Power supply: 9-20 volts DC
• Receive current: 35 mA @ 13.8 VDC
• Power output: up to 1 Watt on the 40 meter band with 16 VDC power supply
• Receiver sensitivity: approximately 10 uV @ 10 dB S/N
• Audio gain: 42 dB + 20dB from Q-Multiplier = 62 dB
• Receiver Selectivity: less than 500 Hz

Schematic

Kit Assembly Guide

Development history.