Any coiled conductor carrying current will have an increased XL [Inductive Reactance], or simply a higher level of Inductance than if the conductor was run straight.
I Think that a tight loop [with a single loop coil of 1" diameter on 1 conductor], the L would be 4 times greater than straight line L.
For a 4" coil, the value might be more like 2.5 times greater than straight line [I'll need to pull out the EE books on this one, I'm just "Shooting From The Hip" here].
Now, if there's a loop with conductors carrying current that oppose each other [flow in opposite directions], that will cancel the cumilitive L on both of them, so even with many tightly wound coils, there wouldn't be a substantial increase of L in this circuit.
BTW: L = Inductance - I hate to write the entire word over and over, so luckilly we have ANSI/IEEE symbols!!
Once again, let me verify this stuff with the books and see what's up. The whole thing is equal to a single turn air coil inductor [in case you were wondering
], unless there are more than one turn, or there's currents flowing the opposite way.
Here's one for fun
Coil the wire for the job loop so there's like 4 layers thick and 20 stacks high, wrapped on a "Bobbin" of 1/2" GRC conduit [only one current carrying conductor].
Now run a wire through the GRC and wrap it through again and again - so it's covering the other winding.
Connect a DC source [Drycell or Battery] to the coil ran through the GRC.
?? What should happen to the AC flowing through the original coil ???
PS: Don't really do this!! Just explain what would be going on if this was done, and think of it as if you did it!
Otherwise........ Shokken Zeee Shi*zen out of ya!! could happen!!