Crystal Radio Magic

[xee2]

So now I can light the LED to a continious glow at night when the statio is at 1000w.

Congratulations. Thanks for the report and photo. Is your only antenna the short wire on top of the primary coil (or are you connecting to an external antenna wire in addition to the fireplace ground)? Please post a link to the page where you got the EPD info.

[jake]

What is it?

So now I can light the LED to a continious glow at night when the statio is at 1000w. The larger primary made that happen. The correct capatance across the primary eliminates all blinking and the little hand is no longer needed.

There is very little improvement when the power goes up in the morning.

What it is:

Secondary - 20 turn coil of 14 gauge wrapped according to EPD. With attention to getting the coil to the proper EPD dimensions. So spacing was what it was.

Primary - Almost 2 turns of Stout Flat copper.
84.5mm wide
2857.5mm long(10mm short) Best I Could Do. Now I need to shorten the Secondary
1.35mm thick (STOUT)

I made this from a 1.25"dia copper pipe. Split it lenght wise on a table saw. Hammered an ax down the lenght to open it up. Used pliers to open one end wide enough to get it in a sheet metal roller and rolled it flat in 12 passes.

FWBR - Of 1N34 diodes across the secondary or from almost any point on the secondary to bottom of secondary.

LED - across the DC of the FWBR.

Ground or antenna? - Bottom of secondary is connected to Fireplace shroud/metal chimney. It is grounded via propane copper tubing but it also acts like an antenna since its big metal and sticks out the roof.



coments and questions are welcome.

[xee2]

BUT I have a slightly smaller diameter cardboard tube. I think it would be a good idea to build a setup based on you way of thinking then I could compare the two. Smaller diameter will allow more turns greater induction for same length of wire.
Can't wait to get out of work.

Not exactly true. Here are some links that may help you:

Inductance Calculator

Web Based Resonant Frequency Calculator

[Web000x]

It sounds like he is saying that the 16 ground rods should be used if you are in a place that stays relatively moist. If the ground is dry sand or rock, you need to use the 80 ground rods of 14 gauge wire. I don't see why you could not use the 80 rod configuration in normal soil. (But I am also not Eric. I'll ask when he calls me next)

Be careful about using solid tubing to wrap coils. The dielectric constant needs to be a minimum. Anything above relative dielectric constant = 1 will retard the wave. This is why Eric builds all of his transformers with wooden dowels, to expose the wires to the dielectric constant of air.

Dave

[jake]

Awesome

@ Web000x:
Good Grounding is on the horizon. What do you think of Eric's recommendation of the 80 ground radials? Is this needed in addition to the 16 ground rods or can this be used in place of the 16 rods. It would be easier to lay out compared to the rods. but the center rod will be 10-20' deep in good soil.

@ xee2:
I wish it was that easy. Problem is the coil I am using now was calculated to have a specific diameter, hight and length. I can't change one without screwing up the others.

BUT I have a slightly smaller diameter cardboard tube. I think it would be a good idea to build a setup based on you way of thinking then I could compare the two. Smaller diameter will allow more turns greater induction for same length of wire.
Can't wait to get out of work.

[xee2]

Eventually when I figure out how to tune the coil without needing capacitors

To lower frequency just increase inductance (increase number of turns keeping everything else the same).

Suggestion: make coil with a lot of extra turns and then cut off turns until the frequency is where you want it.

[Web000x]

That is not the frequency that I'm looking for. See if your meter shows any response around 1400 KHz or 3455 KHz.

I could be wrong but I think that there is not supposed to be a resistor in the excitation loop since there is no symbolic representation of one in the drawing. My interpretation of it is that if you have a function generator with an impedance of 50 ohm then you would use a 1 turn loop with no resistor and for 500 ohm impedance a 3 turn loop with no resistor. This is because you are interested in delivering the magnetizing force to the loop rather than trying to get a maximum power transfer between the oscillator and the excitation loop (where the majority of power would be delivered to the resistance). Try it with and without the resistor just to see if there is a difference.

Also, nobody will light a lightbulb without a GOOD ground. When I was quizzing Eric about how good a 'good ground' might be he said that the ground is a horrible conductor of electricity and that what you are really doing is creating a capacitive coupling to the Earth with the wires so make sure you have PLENTY of wires laying down against or buried in the Earth.

Dave

[jake]

Yes there is another point at ~7200kHz. It's small by comparison to the other.

I was using the method you posted for the secondary to the best of my knoledge. But that's not much. Here is what I did:

For the test coil I used a pretty stout flat copper strip. I could only get it around two times. Placing the function generator across 1 turn of the test coil I set it to work. (always wanted to say that) I was not sure what the 50ohms was for but I figured it was accounted for by the 50 in the function generator.

Come to think of it I was not grounded. Or not grounded well. I will try again tomorrow outside where I have a semi decent ground. Am I correct about the 50ohms? Does the size of wire on the test coil matter?

And yes I have/had an extra coil. I took it off and things started to get better. That's when I realized something was wrong. Then you posted the tuning diagrams and I left it off. But the wire loosened up and now it has shorts all over the place. I'm using uninsulated wire for everything. I think I will move to insulated on my next extra coil.

[Web000x]

Also the bulb that Eric has recommended since is 28v 1.12 watt. I think that will be quite a task. The most I've seen on the scope with my flat spiral coil is 210mV so there's no possibility of lighting the bulb with that. I expect I need much better grounding which will be done at some point, but there's no way of adjusting the windings either so that's about the most I'll be able to do with that coil for the moment. [edit] Although I'm not entirely sure if it will even be possible with a flat spiral at all

It is hard to catch every detail that Eric throws me when I speak to him, but I am almost certain that there needs to be an extra coil in order to get the magnification factor to skyrocket which will in turn light the light bulb. I don't think I've seen an extra coil on your setup, or have I?

Dave

[Web000x]

I saw this post after I posted my last post.

It is quite a troubleshooting mission to tune three coils. I am having extream difficulty tuning one and I don't even know if I am doing that right. but I think I am getting a feel for it. Its hard to tell how much of the tuning should be done with distributed elements alone. As I noted in my last post adding a capacitor no matter how tiny seems to reduce performance. Putting my hand ~1" from the soda can peaks performance. Touching the can kills it.

I have assembled all that is necessary for version 2. It will be the same dimensions as the first unless I can figure out how to lower the resonant frequency about 400kHz. Instead of using 14ga I will be using 2.21mm OD x 0.91mm ID copper tubing. This will more than double the active copper compared to what I have now. I don't know how important that is but it feels right. The primary will have slightly more and can be narrowed down to match. Same for the copper plate primary cap. Now thats a lot of copper. Trust me I have been buying it by the pound at the scrap yard as it comes in.


I do not have a scope capable of the comparison. But I am sure if I can light a 100w light bulb my wife will let me buy one.

Thanks for the input.

I assume that you are using the resonance detection method that Eric had me post recently?

As far dropping the resonant frequency of your coil, Eric had nothing to go off of except his memory for developing those formulas for design parameters. This is all in the experimental stage of getting these formulas correct. It is possible that you need to readjust the constants given by Eric by setting the coil dimensions equal to the measured resonance/constant relations and solve for a new constant. Then you could more precisely target the desired frequency in your next build. That is what I would do anyway if I were trying to adjust the frequency.

Are you trying to parallel a cap with the secondary? I think it needs to resonate at the desired frequency without a cap.

Also, are you finding that there are two resonant frequencies for the secondary that exist in a pi/2 proportionate relation?

Dave

[dR-Green]

I am having extream difficulty tuning one and I don't even know if I am doing that right. but I think I am getting a feel for it. Its hard to tell how much of the tuning should be done with distributed elements alone. As I noted in my last post adding a capacitor no matter how tiny seems to reduce performance. Putting my hand ~1" from the soda can peaks performance. Touching the can kills it.

Use a metal plate connected to earth/bottom of the secondary with adjustable distance from the can, and position it for peak performance. It won't like a variable cap very much across the secondary (unless maybe it actually goes down to zero pF), the type with rotating plates. I think vacuum variable caps might be usable here but they are expensive, so a metal plate near the can should do the trick. You can also lower the frequency by using a bigger can/pieces of metal. I think it's the surface area that applies in this case. Try connecting progressively larger pieces of metal and see what happens.

Also the bulb that Eric has recommended since is 28v 1.12 watt. I think that will be quite a task. The most I've seen on the scope with my flat spiral coil is 210mV so there's no possibility of lighting the bulb with that. I expect I need much better grounding which will be done at some point, but there's no way of adjusting the windings either so that's about the most I'll be able to do with that coil for the moment. [edit] Although I'm not entirely sure if it will even be possible with a flat spiral at all

[jake]

Jake,

Eric said that it is not easy to get three coils to resonate together. It took him about a year at Landers to properly tune his receiver. As xee2 was saying, your magnification factor (Q) will be much higher if you can get the coils into a symbiotic resonance. This heightened magnification factor is apparently what allowed Eric to light the light bulb.

He also said that if you are having trouble getting these coils to resonate then don't use the extra coil and it would still work. However, I don't know if this will light a light bulb without the heightened magnification factor. This might just be for a telluric receiver.

Have you tried using an aerial (dipole) and the TMT style antenna at the same time for a comparison on an oscilloscope? This is what Eric is talking about in order to see the difference in phase angle of the two signals to see that the telluric transmission is propagated faster than the above ground transmission. This would be the evidence of a faster than light propagation.

Dave

I saw this post after I posted my last post.

It is quite a troubleshooting mission to tune three coils. I am having extream difficulty tuning one and I don't even know if I am doing that right. but I think I am getting a feel for it. Its hard to tell how much of the tuning should be done with distributed elements alone. As I noted in my last post adding a capacitor no matter how tiny seems to reduce performance. Putting my hand ~1" from the soda can peaks performance. Touching the can kills it.

I have assembled all that is necessary for version 2. It will be the same dimensions as the first unless I can figure out how to lower the resonant frequency about 400kHz. Instead of using 14ga I will be using 2.21mm OD x 0.91mm ID copper tubing. This will more than double the active copper compared to what I have now. I don't know how important that is but it feels right. The primary will have slightly more and can be narrowed down to match. Same for the copper plate primary cap. Now thats a lot of copper. Trust me I have been buying it by the pound at the scrap yard as it comes in.


I do not have a scope capable of the comparison. But I am sure if I can light a 100w light bulb my wife will let me buy one.

Thanks for the input.

[jake]

The credit for the drawings goes to Eric Dollard. Those are his pictures from the Dollard thread.

And the LED is lit. I am able to take the large 20 turn coil and attach it to either my fireplace or stove vent hood or large metal object(i.e. antenna) and light an LED to a decent glow. It is not full brightness but it was constant and even my wife freaked out a little when I said there was no battery. The other end of the coil has a Dr Pep can.

My first attemts to get a joule thief to brighten up the light were a failure but I will revisit the JT idea a little later as attaching the coil to an antenna now allowes me to light the LED to a level that does not require the JT.

Without attaching to an antenna I can only sometimes get a very faint glow.

ALSO this coil is not resonant at 1620kHz. This is the station that is supplying the power. It is 10kw more than 5 miles away. And at night it goes down to 1kw. Even at night I can see very very faint blips of the LED.

The coil attached to the fireplace surround and DP can is resonant at ~2200kHz depending on where and how I excite it. I KNOW that LED will go balistic if I can get it tuned to 1620. Using a function generator at 1620 will not light the led. Turning it to 2200 will light the LED beyond a glow and one might say bright enough.

PROBLEM!! - Tuning for brightness does not seem to like external capacitors and REALLY does not like alligator clip leads. To get it to where it is now required respacing the turns of the coil and tapping the coil in the right spot. but even that does not let it drop down to 1620

Eventually when I figure out how to tune the coil without needing capacitors I will move on to the extra coil. Using the extra coil now will either help or hinder depending on what I have going on. So I took it off and will revist it when I get the secondary(large 20 turn coil) to 1620.

[Web000x]

Jake,

Eric said that it is not easy to get three coils to resonate together. It took him about a year at Landers to properly tune his receiver. As xee2 was saying, your magnification factor (Q) will be much higher if you can get the coils into a symbiotic resonance. This heightened magnification factor is apparently what allowed Eric to light the light bulb.

He also said that if you are having trouble getting these coils to resonate then don't use the extra coil and it would still work. However, I don't know if this will light a light bulb without the heightened magnification factor. This might just be for a telluric receiver.

Have you tried using an aerial (dipole) and the TMT style antenna at the same time for a comparison on an oscilloscope? This is what Eric is talking about in order to see the difference in phase angle of the two signals to see that the telluric transmission is propagated faster than the above ground transmission. This would be the evidence of a faster than light propagation.

Dave

[xee2]

Any ideas?

Nice drawings.

When the two coils are close they "load" each other. This increases inductance of each coil, decreases Q of resonators, and provides more energy transfer between coils. In crystal radios increasing coupling between coils will provide more energy transfer but also decrease resonator Q. Usually minimum coupling is best since this produces highest resonator Q. If both coils are resonant at the same frequency then the Q of one coil will increase the effective Q of the other coil. This is how coupled resonator filters work. But the resonant frequency will change as the coils are brought closer together so they must be re-tuned after they are moved closer together.

I suggest you try coupling two parallel resonant circuits and tune to same frequency. This should give improved reception. Best if you can tune to frequency of near by radio station.

Or just make one parallel resonant circuit with large coil and weakly couple to it with a single loop or a small capacitor.

I would think your power detector would work better if the diode was in series with the amp meter. The circuit you have would work with a volt meter.

Please keep posting your results. I hope you will be able to light an LED from the RF signal.