The 24-pF capacitor is a disc ceramic type. It must be positioned in line with the cold end of the tank inductor. The link is placed between that capacitor and the tank. The value is not critical. Approximate LC dimensions: MHz Trimmer * L (#24 copper wire) 90-280 6-50 3t, 0.187 diam x 0.185 long 280-400 4.5-30 3t, 0.187 diam x 0.185 long 400-480 2.8-10 2t, 0.100 diam x 0.187 long 480-515 2-6 2t, 0.100 diam x 0.187 long
• Supply current: Less than 20 mA; exact value determined by voltage and crystal activity.
• Coaxial connector and cable output desired for best wave form.
A VHF Crystal-Controlled Oscillator with Negative Ground
This is a circuit from an unpublished manuscript entitled "Practical Overtone Crystal Oscillation above 200 MHz." It is designed for use with chemically milled inverted-mesa crystal wafers with AT temperature characteristics. It has been tested at frequencies from 200 to 513 MHz and at overtone modes from the 3rd to 9th.
Was this article helpful?