This is a rather unusual QRP Power Amplifier design, with a wide frequency response; within three dB's from 300KHz to 30MHz. Overall gain is in the region of 16dB
The receiving frequency can be set with a LC tank or with a crystal.
by Roger Arrick.
This machine has about 12dB gain. And, maximum power is 3 watts
using phase shift network
WA3KEY presents everything you need to know about the Collins 51J4.