crystal radio: the first real free energy device

[scotty1]

Hi guy's. I played around with lots of crystal radio's but this one that I made is by far the best.
Most of the info is here in the clip, although the quality is not HD. I made a drawing that shows it as it is setup in the clip.
My dual gang vari cap was hand made and very crude but it performed much better that the dual gangs I got from old radios!!!
I can get quite large voltages from this setup, and in the clip here it is running a standard wall clock, but since then I improved it even more.
The transmitter is about 25 kilometres from me and I tune to 774khz, but I noticed I get another station which happens to be an octave above at about 1550khz.
I'd really like someone to make one of these to see how it goes....a few more coil taps around the centre of the primary might be an idea too....
https://www.youtube.com/watch?v=LQT01-OA89k

[scotty1]

Also it will run a 4" speaker that has an audio trans pretty well.....and I think my diodes may have been 1n60's in the video.
My latest antenna was just a blue data cable....I joined the 7 cores together at the radio coil end.

[pomodoro]

I just made some homemade synthetic galena, one of a few attempts. Quenching seems to give more sensitive galena than letting it cool naturally.  When the reaction starts, the mixture glows red possibly gets hot enough for the top layer to melt, or so it seems.  The top of the galena looks as if it melted (~1100 C).  Quenching in water is done a few seconds after the glow begins. Water must not be allowed to seep inside the crucible. Use only steel, no glass or ceramic or other common metals. The rough, porous side is set in woods metal or wrapped in aluminum foil.

Compared to two samples of natural galena, the synthetic one is superior. most of the 'melted' side is active and the signal is just as good and occasionally slightly better than a germanium diode.

In the next experiment this synthetic sample will be melted in a steel tube under nitrogen in an electric furnace at 1250C and allowed to cool in the furnace.

[Pirate88179]

Pomodoro:

Very cool experiment.  Keep us posted on the result of your next batch.

@ All:

I have a question about the radio I want to build.  I have been reading on various crystal radio sites about all of the many designs available to build.
One site explained that to get really good reception, your coil has to be in resonance with the desired signal. (Tank circuit)  He explains that you can use just about any wire for your coil, stranded, mag. wire...etc. and the gauge size is not that important.  It is very important that you match the resonance with your signal.  Great.  He does not say how this is done.

I always listen to a local station here (transmitter about 10 miles away) at 930 kHz.  I salvaged an air capacitor from an older am radio and I have my germanium diode.  I want (actually have to now) build this with supplies I already have here.  I went to the coil calculator site I posted here a few posts back, and I can not figure out how many turns of what gauge wire I need to be able to resonate at 930 kHz?  I know I can tune it with the air cap.  Also, I have some ferrite rods I can insert into my coil for coarse tuning.  What I want to make sure is that my coil will be within the range of my tuning abilities to receive 930 kHz while resonating.

Is there an easy way to calculate this?  Wire length, diameter of coil, wire size?  The coil calculator has three variables and you must supply 2 of them to get the third.  I don't know 2 of them at this point.

I have a nice 1.250 x 12" long clear plastic tube that I want to wind my coil on.  I have various sizes of mag. wire here...32,22,18, 38.

I have a nice ceramic earphone and, I plan to use the a.m. antenna I built many years ago that I use on my stereo receiver to get the station I am talking about, as well as many, many others.  I will just tap into it.

Any suggestions would be appreciated.

Bill

[pomodoro]

The inductance of the coil required to resonate will depend on the capacitance of the variable capacitor.  There are plenty of sites with LC resonance calculators eg: (http://www.1728.org/resfreq.htm)
For a typical cap of 150pF it looks like you need a coil of 200uH for .93MHz.

So unless you know the capacitance of the cap, probably try a coil of 300uH for a start. 

if you have an oscilloscope you can easily find the resonant frequency of the coil and cap by pulsing it wit a battery and watching the sine wave.

Also, Litz wire is best for the coil, but not mandatory.