Oscillator multiplier.

Here is the schematics of the oscillator multiplier. It multiplies from 14MHz to 42 MHz.

The design of the multiplier gives a lot of harmonics all the way up to the 21 order at 294 MHz. This might be a good oscillator for transverters all the way up to the 23cm band with a 2GHz transistor. The output transformer will have to be an air-core transformer.

Quick about the circuit.

R1: 47Ω

R2: 10kΩ

R3: 4k7Ω

R4: 300Ω

C1: 0,1μF

C2: 45,5 pF @ 14MHz or 30,32 pF @ 21MHz. I used a 50 pF trimmer.

C3: Ca 40pF @ 14MHz or 50pF @ 21MHz.

T1:  250Ω 14 MHz; 2,83μH, 19T 10mm core 12 mm long. 0,202mm enameled cu wire. Secondary is 10-20% of primary.

T1: 250Ω 21 MHz; 1,89μH, 14T 10mm core 9 mm long. 0,202mm enameled cu wire. Secondary is 10-20% of primary.

To calculate the I used two web pages. The Daycounter for calculating the required inductance and www.circuits.dk to calculate number of turns on the inductor.

66pacific.com does also have a good calculator to reverse engineer the inductors in the schematics.

As showed in the picture there are harmonics up to 21 order, the harmonics over 14 order are more or less neglectable.