This basic VFO for the 3- to 6-MHz range is coirimonly used in amateur applications, using a Colpitis circuit. For 5 to 5.5 MHz, C = C2 = 70 pF and for 3.5 to 4.0 MHz, use 1000 pF. C3 is typically 10 to 220 pF, depending on the frequency. C4, C5, and C6, together with C3, determine the frequency along with LI.
C6 can be made up of several smaller values, paralleled to get the exact required value.