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Radio

I got my amateur radio license (as SM0YSR) in January 2004, and since then I have occasionally active on the shortwave CW bands. My primary interest in amateur radio is building things, some radio-related projects are destribed on this page.

Project Year Description
WSPR transmitter2017 I built a simple WSPR transmitter from an Arduino AD9851 module and an 74AC08 chip driving a 2N7000 MOSFET transistor in a class E power amplifier. Code is available on github.
Trensceiver2006 Probably the simplest "transceiver" out there, with only three components. The schematic contains a crystal, a resistor and a JFET transistor connected to an earphone. This would probably not even oscillate if built with proper RF design (I used a solderless breadboard and long component leads), but if you increase the voltage above the point of oscillation and (lightly) couple the circuit to an antenna, you should be able to hear CW transmissions with a suitable frequency offset. Increase the voltage a bit more, and use the radiated RF as a transmitter!
Baking soda powered radio2005 A small regenerative receiver powered by baking soda, steel wire and some coins.
Spark gap transmitter2004 I built a simple spark gap transmitter with a small transformer (using a power MOSFET to drive it from a 9V battery) and a Cockroft ladder to generate the spark voltage.
80m direct conversion transceiver 2004 This is my only major radio construction/design project, and not a terribly good one. It works pretty fine, though, and I even got on the cover of the Swedish QTC magazine with it.
My Pixie2 tranceivers2004 The Pixie2 is a very small, simple and cheap low-power CW transceiver for the shortwave bands (mine use 3.579 MHz crystals).