Frequency Counter

Features

• Original Design
• AliExpress Frequency Counter - Very inexpensive
• PIC-freq.counter-modification
• DL4YHF 50MHz counter on a Chinese TB-244746 PCB

Case

• P-Touch white on black labels

• Inexpensive plastic case

Rework - Add Pre-Amp

• Pre-Amp schematic
• Based on https://www.youtube.com/watch?v=0BxpMm6SLoE
• Uses extra transistor that would have been used by crystal tester oscillator

• When building kit, do not install

• Front side cuts - blue
• Jumpers Red

• Back side cuts

• Details of preamp input pin

• With parts

Testing

• 4.9152 MHz crystal
• Scope frequency counter shows 4.19520 MHz
• Freq Counter displays 4.9747 MHz
• Difference = 500 Hz or 0.1% accuracy
• Can only adjust the variable capacitor in narrow range