27Mhz toy car transmitter/receiver
L1, L4=9 turns, .15mm wire on 4.5mm diameter tunable ferrite coil former
L2=15 turns, .5mm wire, 5mm diameter
L3=3.5 turns, .5mm wire, 5mm diameter
L1 for 27Mhz is about 10 turns, 6 mm diameter coil body.
Schematic diagram
