Hi,
It depends on the frequency...RC use 27, 35, 41 and 72MHz.
I always use surplus T/o/k/o coils from junk.
For a 7mm T/o/k/o sheilded coil 5 turns give about 0.3µH and 8 turns give 1.0µH. There is a +-20% tunning rage. For example for 72MHz a 0.27µH with 18pF will work. Wind the primary starting at the bottom two slugs (5 or 8 turns) and the secondry (usually 2 turns) at the third.
You will understand what I mean if you have already played with these coils. Or just write to T/o/k/o with your requirement and they will send you free samples
thanks hadihf
i think 2K159 is 1µH (deduction based on some schematics) but i'm not sure, because of parasitic capacitance in tracks
but i cant read value with my LCR meter even if it can reach down to 0.1µH , maybe test frequency is too low ???