You can adjust that after you get the RF oscillator working. The larger capacitor(C2, 300pf or so) along with the 100 k resistor will cause a high frequency roll off of your modulation signal at about 5 kHz. You also need to add that 100k resistor between the modulation source and the varactor. Either you need to make your tank circuit resonate around 100 MHz or change the cap (C2) to 300 pf.
The capacitor from the emitter to collector that I suggested (5 pf) is good for 60x that frequncey but around 1 Mhz the impedance is probably way too high. The RF oscillator is not oscillating.Īt what frequency do you want this to oscillate? Right now it is around the top of the AM broadcast band in most regions -1.6 MHz. All I see is 100 Hz which is your modulation. I would expect the L/C circuit to oscillate at about 1.6 MHz. I didn't look closely at the waveform and only took your word for it.
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