Now that I’m retired and out of the CA and will soon move into in a semi-rural area in another state, I look forward to firing up my National NC-46 and my old ship-borne surplus Hallicrafters S22 shortwave receivers. But it still played! The lightning strike must have cleared whatever non-linearity there was that acted as a detector and blew open whatever was acting as an antenna. After that strike, the plumbing and heater ducts no longer played WBAL, and the crystal radio’s volume went down drastically. During an electrical storm, there was a direct a strike on a power pole less than 50 yards from the house. We could also hear WBAL playing on the heating ducts and water heater in the basement too! It was really freaky.īut all good things come to an end.
He actually had to put in a pot to turn the speaker volume down! His first version required a modification because the music was too loud. My dad built my mom a crystal diode receiver into the wall (no antenna, just a loop-stick coil) that actually drove an 8 ohm speaker (with no impedance transformer either).
“KNX 1070, all news, all the time…” lighting up little LED glow-bugs in the back yard would have been a kick.īack in 1968 my parents had a house that was within eye shot of WBAL’s antennas in Baltimore, MD. I wish I had tried it when I still lived there. I’m not sure if it is enough power at 4 miles to light an led, but you have the right idea. At that power level, it’s hard not to receive it if you line close to the antennas! Even with good LC-filters to get rid of KNX, I still had the power lines to deal with.īTW, according to the web, KNX is now putting out 50KW (which did tend to go down at night). Between the 235KV power lines next to the house and KNX, I had to give up on shortwave listening. I used to live about 4 miles from the antennas in Columbia Park (Torrance). Yeah, KNX was a pain – it came in on almost everything I tinkered together. Posted in LED Hacks Tagged led, wireless led Post navigation We wondered if you could draw power from something that was transmitting anyway. The commercial versions did look a little nicer, but with surface mount components, even the DIY version could probably look a bit cleaner. In the end, there is an economic analysis of building these versus buying them ready-made, but we all know that isn’t always a decision that is strictly based on dollars. What would you do with a wireless LED? Maybe lighting in a model display or a checkerboard? We wondered if you could use two or more power frequencies to signal (for example, 200 kHz lights a red LED but 250 kHz lights a green one)? The original transmitter was fixed frequency, but if you used a microcontroller, it would be easy to make it frequency agile. He also dissects the transmitter, so you could roll your own there, too. used two LEDs to get work out of each half of the AC waveform. Some experiments found that the circuit could supply about 2 mA -3 mA of current. A capacitor resonates the coil and drives the attached LED. Reverse engineering found the transmitter sends 217 kHz into a 2.2 mH inductor. Once you have power, lighting up an LED is no big deal. The LEDs work by receiving power from an induction coil. They may not look as polished, but they work and they are undeniably cool. They were very neatly packaged, but - we like it - he took one apart and made his own versions. Bought some wireless LEDs that receive power from a base station.
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