SOP Receiver Assembly Manual

Thanks for purchasing the SOP Receiver Kit from the NJQRP Club. This section of the manual provides a basic technical overview of the design and operation, and details the assembly required to make it a functional receiver in your shack. The SOP (Seat-Of-the-Pants) is intended as a utility CW receiver, useful in the shack to complement some of the simple transmitter projects available today (Tuna Tin 2, Fireball 40, etc.); or for use in the field because of its low power consumption and small size.
It uses a simple direct conversion technique and is well-suited for experimentation. Though designed originally as a companion to the NJQRP Fireball-40 transmitter, it is a “natural” to team up with any simple QRP transmitter. Another use is that of band monitoring. The SOP provides an elegant way to listen to a band wherever you might be.
The SOP incorporates an audio low pass filter to minimize off-frequency interference but by design is not so selective that nearby signals cannot be heard. While superheterodyne receivers offer better performance, the SOP’s simplicity makes it easier to tune up on anywhere in the HF spectrum for CW (or SSB) reception.

Source