Copper wire ferrite core coil inductor for GPS

Ferrite is just a powder of oxides of iron. This powder is mixed with an epoxy resin and molded to form cores around which wires can be wound. Ferrite core inductors are easily the most recognizable because of their dull grey-black colour. They also are very brittle and break easily. They are the most widely used kinds of inductors, since the permeability can be finely controlled by controlling the ratio of ferrite to epoxy in the mix.
Inductors in Series and Parallel
Inductors connected in series and parallel behave the exact opposite way to capacitors.
For example, to calculate the inductance of a group of inductors in series, you can simply sum up the values of the individual inductances.
L = L1 + L2 + … + Ln
Where L is the total inductance and L1, L2…Ln are the individual inductances.
Suppose you have two inductors, one measuring 10uH and the other 15uH, then by putting them in series you obtain a total inductance of 25uH.
Inductors in parallel behave the same way as resistors in parallel, the inductance is given by:
1/L = 1/L1 + 1/L2 + … + 1/Ln
Where L is the total inductance and L1, L2…Ln are the individual inductances.
In this way if you connect two 10uH inductors in parallel, you’ll end up with an inductance of 5uH.