“Those who hear not the music, think the dancer mad”
PW Sprat
What Is It, 13th Feb 2005

The PW Sprat - 80m CW Superhet


Feb 13th - Today I purchased a QRP radio from the excellent Harwell rally. I was after some help to identify it?

It consists of

Left PCB marked WR349 (Sprat RX) copyright PW publishing 1996

1 * MC3362P (!)
1 * LM386
5 * 4.433615 Crystals

Right PCB - no markings
1 * 602
1 * 2n3866

Found some interesting links

The chip on the RX board, an FM receiver on a chip

Used in a 7Mhz CW TRX

The block diagram of the 7MHzCW transceiver made of MC3362P and the explanation

HF Receiver Using MC3362

I have made a few more enquiries, and posted on the QRP yahoo group. Got loads of replies! Offers of the original circuit diagram from 1996 PW project, and found out the rig was originally owned by the chairman of the Oxford club. Circuit diagrams are on their way! Another project!


“The little fishes of the sea, They sent an answer back to me..”

Feb 21st - Nigel M0DBO kindly sent me a copy of the original PW article. The Rig is a 1996 PW project, the "Sprat Tranceiver - 80m CW Superhet" designed by the Rev George Dobbs G3RJV. Reading through the articles, and aided by a glass of Goose Island IPA I take a look at the kit, and see what the "extra" boards are.

The board bottom on the right of the photo, is wired between the TX antenna input and the RX it has 4 diodes as input protection and is some kind of RF preamp. The copper board at the bottom of the second photo, is an amplifer between the rx local oscilator output and the TX.


PW Sprat Close up
The PW Sprat - Front
PW Sprat Inside
The PW Sprat - Inside