Stubblefield coils (bifilar) and speculations

[jeanna]

The meter is supposed to be able to read 5Hz to 10mHz.  It just kept bouncing around between low Hz numbers to kHz numbers.

Don,
But that is right!
Your meter is reading the pulsing that my scope is showing.
Look at the right hand side of the meter screen and it will say what you are seeing. I see from 2hx to 5Mhz depending...

I think this explains what my scope is picking up,
http://www.youtube.com/watch?v=xfwMFrqGtaE

and it sounds to me like you're seeing the same thing.
I think if you watch my video with this in mind, it might make you feel better about all that jumping...

It is real.
yeay! 


jeanna

[Pirate88179]

The meter is supposed to be able to read 5Hz to 10mHz.  It just kept bouncing around between low Hz numbers to kHz numbers.


That website states my inclination is 68 degrees 45'.
Does that mean i have to lower the bottom of my + northern rod 68 degrees lower then the bottom of my - southern rod?
But at what distance between the rods?  45'?
Their FAQ help isn't very helpful 

DonL

Don:

First, that site has nothing to do with what we are doing other than it tells you info you need to know about your area.  It will not calculate the distance needed between your electrodes.  This is pretty easy but there are variables and if you change one variable it alters everything.  I started (I did this the easy way as I hate trig) with my south electrode and planted that to a reasonable depth.  After looking up my local info on that site,  I could see that for my electrode angle (measured from the bottom of one electrode to the bottom of the other) to be close to my dip angle I needed to put my north electrode X deep at X distance.  I would have to draw it out but I believe the further apart your electrodes are the greater your angle gets if the depths remain constant.  If you put this on paper you will see what I mean.  Some of the parameters you are stuck with like possibly, the length of your electrodes, and for sure, the dip angle of your area, and maybe if you are like me, not much space to work with.  So, you can vary the other parameters and hopefully get something close.

Bill

[oscar]

Hi dllabarre
http://www.ngdc.noaa.gov/geomagmodels/IGRFWMM.jsp

...That website states my inclination is 68 degrees 45'.
Does that mean i have to lower the bottom of my + northern rod 68 degrees lower then the bottom of my - southern rod?

Hi dllabarre,
yes, this is how I understand it.

I just looked up what inclination the website would give for my place (in Europe). It came up with 60°.

I did not expect such a high value. Here an example for what that means (in my understanding):
With electrodes spaced 1 foot apart from each other, the one in the north would have to be buried more than 1 foot deeper than the south electrode.

I then calculated it to get the exact value.
tan(60°) = 1.7
So for 1 foot distance between the two, the north one would have to be 1.7 foot deeper than the south one.

If the electrodes are 2 feet apart, the north one would need to be buried twice that deeper, which is  2*1.7 = 3.4 feet.

Calculated with the ca. 68° inclination at your place I get:
tan(68°)
which means 2.5 feet down for every foot distance on the surface.

That seems really drastic, but you can see that the "Vertical Component" stated by the website, is much higher than the "Horizontal Intensity".

[Pirate88179]

Oscar:

Thank you.  Nice job.  You are obviously much better at trig than I am, which is pretty easy to do, ha ha. 

Just for the heck of it, what is your magnetic deviation from true north over there?

Thanks again.

Bill

[sm0ky2]

hi guys,

i used Bill's cheat-sheet, on "how to make an NS coil"
[ if i had a time machine i would have gone back to get some cotton-coated wire....]

but im a little too lazy (and time deprived) to read through 95+ pages right now.....

so umm....   How do i use this thing?? what are we 'supposed to do' with it?
i have 4 leads comming out of it. 2 copper + 2 steel.