Tuesday, August 11, 2015

@MAKE #Electronics Experiment 31: One Radio, No Solder, No Power with thanks to @sqfield (+Simon Field)

This is one of those things I've wanted to do for over 55 years.  If I'd only had more motivation and more support, I would have.  Water under the bridge, so here's my attempt now.

First of all, contrary to Charles' title, there was solder: I was too aggressive with my stripping to create the tapes in the coil, and cut the wire, so I had to solder the two pieces together and add some heat shrink for insulation.


Parts ready for assembly: coil with taps ever 50in, wrapped around vitamin bottle, spool of solid core 22awg hookup wire for ground--40ft left after the coil, germanium diode (on top of the white spool), 100ft og 16awg stranded wire for antenna, piezoelectric earphone, hose clamp to connect ground wire to water pipe. The earphone I bought (from SciToys) has a plug on the end, so I bought a jack for it from Radio Shack and connect the ground and earphone wires to it.

This is +charles platt 's experiment, but he directs the reader to scitoys.com for parts. This website, run by +Simon Field, has a wealth of fun projects.

Before adding the coil and the antenna, I tried a couple of suggestions from SciToys. First, I touched one end of the diode to a water pipe for ground and the other to the ground contact on the phono jack. I held the audio input (left, because it's a stereo jack and the left is where the contact on the mono earphone is) to use my body as an antenna. Got nothing.  Next, I taped the hookup wire to the water pipe and cut off a length of wire that would allow me sit in a chair on my patio, and connected that to the ground on the jack with an alligator clip.  I connected one end of the diode to audio input and held the other end, again being the antenna. Still nothing.

There is an AM tower within about 3 miles, so I think I should be able to get something. Next, I tried adding the coil and the 16awg antienna.  There is lightning in the area for the next couple of days, so I stayed inside: I ran about 60-70ft of wire up the basement stairs through the living room and around the family room. Then, I went back to my basement workshop and assembled what you see in the photo below.
The black and red wires at the bottom go to the water pipe and upstairs.  The green alligator clip lead goes from ground on the jack to the taps on the coil. The red alligator clip lead goes from the diode to audio input on the jack. The paper clip hanging from the tap (upper left) marks where I heard something.
When the weather clears I'll try the antenna outside, but here's what I got:

  • I heard static right away in the earphone
  • When I moved from tap to tap, the static went away--silence
  • At one pint, on one tap, I heard some Spanish--SUCCESS! I couldn't get it back, but I'm happy
I will post again after I move outside. I have some other components too, like a variable capacitor and a coil+ferrite rod, so I will plan adding those while I'm waiting for the weather to clear.