Crystal Radio Magic

[madhatter]

Have now drawn both the Multiply and Divide situations out on paper and you can see why the Eric/Tesla situation will make it difficult to tune.
In the MULTIPLY way which is my way, the 0.637 'average AC wave' point is on the UPCURVE of the frequency waveshape slope.

In the DIVIDE way that same point is on the DOWNCURVE slope.
So what we are seeing is an opportunity to tune in the first instance and only a brief and parting opportunity in the second instance.
That is sufficient evidence for me as mine required NO tuning where the other is said 'to be difficult to tune' and there is your answer as to why above.

OK have attached the drawing and hope it comes out viewable.
Math also shows the difference in length involved and how it is calculated.
Have always had this notion that all of this should not be difficult if we are to work at the correct operating points.
Thanks.

Smokey

the 0.637 is not the AC average but the rms of 1/2 of the sine wave of a DC rectified current. AC average or rms of a full wave is 0.707 or sine45*, cos45*.

If the extra coil is designed around C and harmonics at velocities of C it will only continue to receive hertzian waves. The extra coil dimensions that Eric supplied should be useless in reception of hertz transmission in air.

[jake]

5) PI over two; this factor appears twice in the Crystal Radio Initiative, C.R.I. The (20%) secondary coil "effective" propogation velocity is the velocity of light in the space in which it occupies. Here the Pi over two factoris an offsetof a unit value to shorten the winding to compensate for the heavy external loading that the secondary is loaded with, that is, the external inductance and capacitance from the earth and extra coil connections. The aspect ratio of 1 to 1 on the extra coil gives an "effective" propogation of 187% the velocity of light, hence the winding length must be made greater in order to get a quarter wave resonance at a higher speed. This is brought down to Pi over 2 percent, 157%, the velocity of light to compensate for the burden upon the extra coil, this mostly arising from the dielectric upon which this coil is wound. The secondary is Pi over two shorter, the extra coil is Pi over two longer. Golly Mr. Wizard that's Pi squared over four! Do not hunt for magic where it is not, this is all experimental. So go experiment.

This is all I know about the extra coil according to Eric.

[David G Dawson]

Why Hard to Tune?

Have now drawn both the Multiply and Divide situations out on paper and you can see why the Eric/Tesla situation will make it difficult to tune.
In the MULTIPLY way which is my way, the 0.637 'average AC wave' point is on the UPCURVE of the frequency waveshape slope.

In the DIVIDE way that same point is on the DOWNCURVE slope.
So what we are seeing is an opportunity to tune in the first instance and only a brief and parting opportunity in the second instance.
That is sufficient evidence for me as mine required NO tuning where the other is said 'to be difficult to tune' and there is your answer as to why above.

OK have attached the drawing and hope it comes out viewable.
Math also shows the difference in length involved and how it is calculated.
Have always had this notion that all of this should not be difficult if we are to work at the correct operating points.
Thanks.

Smokey

[David G Dawson]

Extra Coil Math

Goint to be away for a week so will make an itemised listing of the Math now.

Crystal Set Iniative Extra Coil:
In brackets are the figures for my situation.

1. Write down the frequency of the local AM Radio Station you are building the Crystal Set to receive from. (1.557 Mhz)
2. Multiply this number by pi/2 - this is the 1/4 Wave frequency (2.4457 Mhz)
3. Multiply this number by 4 (9.7829 Mhz) - this is the Full Wave frequency
4. Use your Frequency & Wavelength calculator to find the total length of wire required - this is what I use:

FREQUENCY & WAVELENGTH CALCULATOR

My length of wire = 30.645 meters or 30645mm
I use the same size awg (14) as for the Secondary which means the Copper masses are equal for all of Primary/Secondary and Extra Coils.
Length of Secondary = length of Extra.

5. Calculate Coil diameter with We = 0.4 Ws (195.2mm)
6. Calculate 1 turn using 2pi r = (613.24mm)
7. Divide this number into your total length (30645/613.24 = 49.97) = number of Turns
Suggest at this point that you wind a few extra for tuning purposes and then with Headphones on, tune for a maximum by probing back along the coil.
8. Use another tin can about 6 to 12" away from your Extra Coil to hang your 1N34 probe onto, doesn't need to be oriented in any way.
Those of you with excessive local transmitters may be blown off the map so be warned.
Mine is only a 2 Kw.

If at step 2 you were to DIVIDE that number you would arrive at the point where both Eric/Jake's Spreadsheet & Tesla would be working at.
This is in my view the wrong point as it brings you back into a 1/8th Wave and not just before the 1/4 Wave where the 0.637 'average AC Wave' becomes a significant factor.
This is the exact point where your local AM Radio Station sits at.

That's it.
Will work on the theory while I am away as I need to know the electrics behind all of this.
David,
Would be appreciated if you could get this Post to Eric as he may be able to see what is happening here.
This one he can simply copy down the instructions on paper from the phone.
First time I have ever seen a pi and average AC wave association.
Bottom line is that this arrangement works.
Goint to enjoy this holiday, first in about 5 years.
May call in while I am away.
Thanks.

Smokey

[xee2]

What will the 2 turn primary and capacitor do to the resonant frequency of the secondary when I excite them both?

When close together the inductance of each coil will be increased by the other coil. The coil with the highest Q will primarily effect self resonant frequency. You should set SRF of secondary then gradually move primary closer re-tuning the SRF of each coil as you move them together.

This is how I measure self resonant frequency.

[madhatter]

a note also in the CSN of Tesla on Picture V. Extra coil connected to the secondary at 3/4 turns from ground connection. any idea on what 3/4 turns means? 3/4 of the turn or 75% of the total number of turns?

[madhatter]

Yes, and it doesn't work.
My old design as per my instructions worked first off without any problems and was picking up the signal from the 1N34 probe head into high impedance Headphones from 8 to 10 " away from the Extra and this was on a piece of metal used as a neutralising capacitor in an old RF transmitter without any specific direction of alignment.
It was obvious that the coil was radiating as well as magnifying the signal and was of a Telluric nature.
It is very clear in Tesla's Colorado Springs Notes that the length of the Secondary be equal to the Extra and this is NOT the case in Eric/Jake's example but is in mine.
I will put up some pics of both so you can see what I am talking about.

Just getting used to the procedures here at Energetic and always thought it was a neat means of display and communication.

Busy day here building the 3rd Coil but will come back later and put my formula into a step by step instruction so that it can be easily followed.
I am/was most familiar with spreadsheets but will leave that to the keen ones like Jake if he would like to build a new sheet for this working proposal at some later date after I have the 3rd coil working.

The final Colorado Spring's organisation only had 17 turns on the Secondary but I am using 20 as instructed but have a tap at 17 for testing purposes.
I, like Eric, spent many hours digesting the CSNotes and have come away with a different theory than Eric which works.
Eric leaves me for dead with the engineering data side but I have intuition on my side which has worked very well in the past.
Thinking about my working theory and I need to progress on that from an engineering viewpoint.

I have spelt it all out in the Posts but may be difficult to follow.
No, Phi is not involved here so far as no connection has been found.

On the new coil I will allow for fine tuning for a peak as the last one was just as built and could probably have been improved considerably and will fit this stage into the final Math.
Currently reading Eric's 'The Tesla Transformer' and can see some new holes there that need filling.
Later on this.

Smokey

Jan 2, 1900:

New Extra coil, 98 turns last modification.

25' 11" turn length = 98.99" Dia coil.

Still a 1:1 coil and there is notation of various 'tap' points on the primary and secondary to bring them into resonance.

[jake]

Whats going to happen next?

I got my hands on a piece of copper flashing 59" x 7". That is about as good as it gets for me. Right size, Right volume, or close enough to start. This will be my primary capacitor and connecting lengths. My thought is a simple two plate capacitor.

cut it like this.. and the thinner strips solder to the primary.


By jastermake at 2012-04-30

BUT, before I cut...

What will the 2 turn primary and capacitor do to the resonant frequency of the secondary when I excite them both? I'll be using the same 1 turn strip and function generator I used to test the secondary?

What else should I consider when designing this capacitor? Please keep in mind this capacitor may play more than one role in this setup. I believe Eric called this capacitor the 'energy transformer' in one video.

So.... what will it do?

[xee2]

Just getting used to the procedures here at Energetic and always thought it was a neat means of display and communication.

Thanks for the reply. For your information, you can post images here but the storage space is very small so it will fill up quick. This is probably best to start with. But you will need to use and paste the link into your post here when your space is filled up. They now require setting up an account. Setting image size to 640x480 or 800x600 will fit on screen best. There is a preview button that allows you to check how your post will look before actually submitting the post.

[David G Dawson]

Extra Coil detail

@ David G Dawson

Have you built an antenna using the same EPD design that Jake is using? If so how well does it work?

Yes, and it doesn't work.
My old design as per my instructions worked first off without any problems and was picking up the signal from the 1N34 probe head into high impedance Headphones from 8 to 10 " away from the Extra and this was on a piece of metal used as a neutralising capacitor in an old RF transmitter without any specific direction of alignment.
It was obvious that the coil was radiating as well as magnifying the signal and was of a Telluric nature.
It is very clear in Tesla's Colorado Springs Notes that the length of the Secondary be equal to the Extra and this is NOT the case in Eric/Jake's example but is in mine.
I will put up some pics of both so you can see what I am talking about.

Just getting used to the procedures here at Energetic and always thought it was a neat means of display and communication.

Busy day here building the 3rd Coil but will come back later and put my formula into a step by step instruction so that it can be easily followed.
I am/was most familiar with spreadsheets but will leave that to the keen ones like Jake if he would like to build a new sheet for this working proposal at some later date after I have the 3rd coil working.

The final Colorado Spring's organisation only had 17 turns on the Secondary but I am using 20 as instructed but have a tap at 17 for testing purposes.
I, like Eric, spent many hours digesting the CSNotes and have come away with a different theory than Eric which works.
Eric leaves me for dead with the engineering data side but I have intuition on my side which has worked very well in the past.
Thinking about my working theory and I need to progress on that from an engineering viewpoint.

I have spelt it all out in the Posts but may be difficult to follow.
No, Phi is not involved here so far as no connection has been found.

On the new coil I will allow for fine tuning for a peak as the last one was just as built and could probably have been improved considerably and will fit this stage into the final Math.
Currently reading Eric's 'The Tesla Transformer' and can see some new holes there that need filling.
Later on this.

Smokey

[ewizard]

David,
The 1.557 Mhz is my local Radio Station that I am tuning into.
If you follow my last Post it is fully exampled there and shows what I feel Tesla would like to have done but couldn't due to technical shortages of his equipment or he may have just gone the wrong way.
<snip<
Smokey

That's why I thought you chose 1.557 Mhz. I can get lucky sometimes Good to see you here Smokey! I've been on Bruce Perreault's list for something like 15 years and have seen you there as well as the OU forum. Always enjoy your posts. While I've built crystal radio's long ago I'm not really up to speed on this thread. Would you say your concept is anything like a scalar energy receiver?

[madhatter]

Not fun.

So it comes down to "A/(A*Pi/2)=0.63661977"

why not fun?

I think you mean, 'A/(A(Pi/2)=0.636619772'

What I was getting at was that 0.6366.... is a function of Trig. As Smokey mentioned the A/C useage it's the rms multiplier value for 1/2 of the sine wave of a rectified wave for DC. and .707 is the full wave. a lot of these 'numbers' will factor back out and can seem 'magical', they do help in recognizing patterns and relations though.

[xee2]

@ David G Dawson

Have you built an antenna using the same EPD design that Jake is using? If so how well does it work?

[jake]

some fun with math.
300,000,000 x Pi/2 = 300,000,000 x 1.5707 = 471,238,898.04
300,000,000/471,238,898.04 = 0.636619772
1/(Pi/2) = 0.636619772
2/Pi = 0.636619772
0.636619772 x (2 x Pi) "revolution" = 4 "radians"

Not fun.

So it comes down to "A/(A*Pi/2)=0.63661977"

[madhatter]

some fun with math.
300,000,000 x Pi/2 = 300,000,000 x 1.5707 = 471,238,898.04
300,000,000/471,238,898.04 = 0.636619772
1/(Pi/2) = 0.636619772
2/Pi = 0.636619772
0.636619772 x (2 x Pi) "revolution" = 4 "radians"