Square Coil

[plboy]

hi All L=(d*d * n*n)/(18*d + 40*l), where
L - inductance, uh
d - diameter, inch
n - turns
l - length, inch

[plboy]

hi All L=(d*d * n*n)/(18*d + 40*l), where
L - inductance, uh
d - diameter, inch
n - turns
l - length, inch

L=n*n*0.025*d/2.54
n - turns
L - inductance, uh
d - diameter, inch

[Geo]

I can not recommend square coils. They are inefficient.
Try to understand, why the nature is allways producing PI (3.141592654).

Coils should allways be circles. Any mismatch to a exact circle will cause inefficiency. Even the elliptical coils are not recommended. This is the result of 15 years experience and making dozends of coils. Even computer simulations shows the inefficiency of such coils.

Trust me!

I use a 60cm X 60cm coil without any problem.
Before time i used a 1m X 1m coil with very good results.
Maybe near the perimeter the sensitivity to be a little less but nevermind

[plboy]

I use a 60cm X 60cm coil without any problem.
Before time i used a 1m X 1m coil with very good results.
Maybe near the perimeter the sensitivity to be a little less but nevermind

maybe you have a problem vith wire (type of the wire)
What type of wire do you use Al or Cu
test with other type wire

[Geo]

maybe you have a problem vith wire (type of the wire)
What type of wire do you use Al or Cu
test with other type wire

No... i have not problem.
If i remember OK at the 60x60 coil i use a 0.6 mm wire. At the 1x1 coil i used 1mm wire and a resistor in series with it.
All wires are Cu.

[plboy]

No... i have not problem.
If i remember OK at the 60x60 coil i use a 0.6 mm wire. At the 1x1 coil i used 1mm wire and a resistor in series with it.
All wires are Cu.

how resistor can chance inductance ?

[chemelec]

how resistor can chance inductance ?

It Doesn't Change Inductance.

But Reducing the Coil Drive Current can sometimes Increase Sensitivity.

[plboy]

It Doesn't Change Inductance.

But Reducing the Coil Drive Current can sometimes Increase Sensitivity.

Have you done a IB Minelab Relic Hawk

[786]

i need your Frame.

Let's go again. Let's convert the square coil to circle.Perimeter of the 60x60 coil = 60x4=240cm
perimeter=2*pi*r so r=perim/2*pi = 240/6.282 =38.2 cm.
coil diameter=38.2*2=76.4 cm =30.07in
Now from Gary's site (Inductance calculator, august 2003) we have:
Coil inside diam=30.07in
wire=20.5 AWG
coil length= 0.3in
L=0.722 mh
It is near with my inductance meter and far from technick.net calculate for square coils.
Now lets try with technick.net formula.
N=22
R=0.382 m
a=0.0005m
mr=0.99999
L=1.56mH:confused:

Smething is wrong. Lets try the other foormula as Leto wrote.
(N * A)^2
------------- =L
9A + 10B

L= inductance in micro Henrys
N= the number of turns
PI= 3.141
A= is the mean radius in inches
B= the Length of the coil, in inches (not WIDTH !. Two turns at two turns per inch = 1 inch !)

L=(22*15.04)^2/(9*15.04+10*0.3)=109481/138.36=791uH

It is near with my inductance meter (780uH)

OK. I will keep this size. So the other times i will believe everythink that shows the ind.meter.
Thanks Leto

Now for radioactive. Yes the dip meter is very good solution but this time i have not one. It is very easy to construct one but the main problem is the calibrate of indications
My Regards
Bye

how you calculate B that get (i can not understand
B= the Length of the coil, in inches (not WIDTH !. Two turns at two turns per inch = 1inch !)
please by example show it to me .
what happen that B gets =0.3
i need your Frame.
please with same 60*60.
thanks alot dear geo