What is the minimum bill of materials for a working amateur radio transmitter? Looks like you could get away with seven pieces, right eight if you contain the walnut. You must have a walnut.
Some hams love the challenge of QRP or the deliberate use of low-power transmitters to make remote contacts. We got covered the world of QRP previously and found that while QRP rigs don’t do much, that doesn’t mean they have to be easy. Some get quite complex and support many different modulation schemes, even digital modes. With just a single 2N3904 transistor [Jarno (PA3DMI)]The tiny transmitter can’t do much more than send Morse with CW modulation, but since this is done inside a walnut shell we have no complaints. The two halves of the bowl are joined together and contain a piece of perfboard for the simple quartz crystal oscillator. The prototype was tuned outside of the case, and the 9 volt battery is obviously external, but other than that, it’s nothing but crazy.
We’d love to see [Jarno] Add a spring to the hinge and contacts on the shell halves so no keyer is required. Who knows? After that, Castanet-style keying on ham could be all the rage.