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
- BNC connector
- 5.1mm Chassis mount power connector
- 7-9V in
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
Reviews / Builds