First-Hand:My First Handmade Radio
I attended the Nankai middle school in Chungking during the last two years of World War II. Our school was a boarding school and we had strict rules, much like in the army training camp, that the lights were out at 9:30 PM and the bugle will wake us up at 5:30 AM every morning. In order to pass time during these long nights, and not to disturb my fellow class mates, I rigged up a simple super-regenerative crystal radio. This radio consisted of a five-foot long enamel wire for antenna, an RC tank circuit for channel selection, an earphone, and a point-contact copper oxide crystal rectifier. I bought the crystal from a local herbal medicine store, and the contact was made with a bent needle. There was no battery or any energy source for this circuit except the radio energy received from the antenna. I was lucky that there was a radio station with a huge broadcasting antenna located just a mile from our school, so the reception was great and the sound from the ear phone was loud and clear. This radio served me well for many months until my extracurricular activity was discovered by our dormitory director. After much begging, I was able to keep my earphone, which I spent about one month of my allowance to pay for, but my first handmade radio was confiscated.
With this brief introduction to radio, I joined the Chinese Amateur Radio League (CARL). As I recall, this organization was affiliated with IRE, the predecessor of IEEE. I still have a CARL pin which I plan to donate to GHN as an item that may be of historical interest.