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GQRP’s Sudden Receiver Project


The history of QRP stands with many groups that emerged in the ’70s and ’80s both here in the U.S. and also abroad.  A group in the U.K., The GQRP group is responsible for a number of great designs in QRP, books and also a quarterly magazine called SPRAT. The GQRP has developed a complete QRP station in 3 kits, under the moniker “Sudden” for an area in England where it was developed. The Sudden Receiver, The Sudden Transmitter and The Sudden Tuner all of those things plus a battery, some wire and a key and you can be on the air!  Even better is that you get the education of understanding how your ham radio equipment works at the circuit level.

I Recently ordered the first module, the “Sudden Receiver” for the popular HF band of 40 Meters.  Why is 40 Meters so popular, well as it turns out 40 meters works well during the day and the night and the length antenna needed is not unreasonably long.

The design of the Sudden is a DC or Direct Conversion scheme and it uses two popular and often used IC’s in the QRP Builders quiver, the NE602 (or NE612) and the LM386 Audio Amplifier, all other components are pretty standard and the nice addition of other DC Receivers is that it uses Inductor ‘Cans’ instead of toroids and wire windings.  The circuit board design is a Manhattan style of construction with no through hole parts and all the pads are ready for tinning prior to placing each part, this “Limeric” style is the idea of Rex Harper / W1REX the proprietor of QRPme.com. Rex has been carrying the QRP Torch for many years and continues to offer many projects including the Tuna Tin II and he as continued the Rockmite Xfer after Dave Benson retired Small Wonder Labs.

The build was an enjoyable evening project and I found the majority of the build well documented and also organized in easy to follow steps.  On a scale of 1 – 10 difficulty I would put it at 3 and that is only because the fitting of the case takes some care and planning.

Below is my a little video I put together documenting the build and showing progress and later use on listening to 40 Meter CW and Sideband.




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