I just bought a new MagCheck 95 single access AC magnetic field sensor. I am able to measure the AC characteristics of the diypemf magnetic fields coming out of the coils. The MagCheck plugs into my oscilloscope, and I can see the exact waveform coming out of the coils, with a frequency range of 25Hz to 3000Hz, and up to 50 gauss magnetic field strength.
There are a few factors that cause distortions of the input waveforms – too much volume, too low frequency for some waves, and an unbalanced waveform.
Here is what a clean 500Hz sine wave looks like (the volume on my iPod touch is at 8 out of 10):
When the volume is at to full, the sine wave looks as clipped as follows:
Because of the following attribute of the output of the headphone jack, where the output is decoupled from the headphones with a capacitor as in the following circuit, low frequency signals are distorted as seen in the following graphic:
Here is an example of low frequency distortion as described in the above graphic. Here is a 25Hz square wave, distorted:
Here is a square wave at 500Hz, less distorted:
Here is the Lilly wave at 25 Hz:
Here is the Lilly wave at 500Hz, looking much better:
The capacitor coupled output also causes distortion of the pulse wave. The pulse wave is intended to be a positive offset only waveform.
The audio file for a pulse wave looks as follows:
However, when measured, the output looks as follows:
The capacitor in the output circuit balances the area above zero with the area below zero. Unfortunately, this makes having a north pole only magnetic field impossible unless one adds additional circuitry to add a positive Direct Current offset.
The other benefit of having this new magnetic probe is that I can measure magnetic strengths beyond the 100 milligauss limit of the TriField meter. In the above graphics, 1 millivolt is equal to 1 milligauss. In the clipped sine wave, the magnetic strength is around 300 milligauss, in the pulse wave above, the magnetic strength is around 250 milligauss.
[January 29, 2015 Update] I was measuring the various frequencies and waveforms I used on this blog post with the Spooky2-XM generator, and I noticed the same distortions on the low frequency waveforms. This got me wondering what the MP3 output looks like without the coils, by simply measuring the output out of the headphone jack with my oscilloscope. What I found was surprising, that the output waveforms are very clean even at a low frequency of 25 Hz. The following images are taken directly from the headphone output.
Very little distortion on a 25 Hz square wave:
Very little distortion on a 25 Hz Lilly wave:
The 25 Hz pulse wave, though not perfect, is cleaner than the waveform coming through the coils:
This leads me to believe that the distortions are either coming out of the Alleva-Wave coils themselves, or the MagCheck 95 probe is introducing this distortion. The MagCheck 95 probe documentation states that the probe is highly accurate from 25Hz to 3000 Hz. So perhaps its the coils introducing this distortion.
Anyone still checking this out? Before pulling the trigger on a Spooky 2 XM for Lyme, Bartonella, stomach death, etc. I built my own coil and it is working well. I do have one question I seem to be having trouble determining which side of the coil is North… I am using neodium magnets suspended with thread and when I play the MagnetTest audio file the magnet sure does dance, so much so that it looks like the coil alternates between equally attracting and deterring the magnet. Is there any other easier way to determine which is north without a compass? Am I missing something huge?
With your own coil, you can use the right hand rule, where the fingers of your right hand point in the direction the current is flowing through the wire, your thumb then point to the north pole. The frequencies on this website use alternating current, that is, the current goes both positive and negative. This means the north and south pole are constantly changing because the direction of the current is constantly changing with each period of the waveforms. You would need an audio file that used a 100% positive offset waveform where the voltage never goes negative to have a north pole that didn’t always shift.
Hello, I happened upon your blog and have found it extremely helpful. I like the idea of using my phone to have low intensity PEMF throughout the day and went ahead and purchased the coils. I also recently purchased a high intensity machine that I want to test myself, and I was researching how I can measure the Gauss which is how I found your site. I also want to measure the wave form, HZ and distortion levels which I assume is done with the oscilloscope. I was wondering if you could possibly elaborate on how to best go about using the oscilloscope with the Gauss measuring device (you mentioned connecting them together?), as well as if you know of one possibly suggest which devices I might need that can go higher like maybe up to 300 Gauss or even higher if possible. I would like to be able to measure down to 5hz if at all possible. Thanks ahead for any help you may provide.
This post uses the MagCheck device, that can measure up to 50 gauss between the ranges of 25-3000 Hz. Beyond that, I don’t have an answer for you.
Hi Prana,
I have been inspired by your blog to create a simple PEMF using an old motor controller. My biggest struggle is finding information that details the signal being sent. Can you offer any direction for me to find specific details on these signals that would allow me to recreate them. My initial plan is to create a simple pulse with switching polarity that I can adjust the voltage, duty cycle and frequency. But eventually I would like to expand it with more options.
Thank you ,
Eric
If I understand your question correctly, you can hook up the leads coming from your controller to an oscilloscope and measure the voltage and frequency out of the controller. This will give you an idea of what your controller is doing.