Difference between revisions of "HW-9 VFO"

Revision as of 22:24, 26 September 2020

This is a work in process - Gathering pieces.

Replace HW-9 internal VFO with a digital VFO
- HW-9 VFO has legendary issues
  - Mechanical issues with vernier
  - Drift due to thermal
  - Lack of resolution
Fits within HW-9 VFO Box
Controls Tx/Rx/BFO frequencies with rotary encoder
- 10 Hz steps
DD1306 OLED Display
- I2C Interface
- "Curved" display
Uses RIT control on HW-9
- +/- 1 KHz RIT
Blue Pill Microprocessor
- Arduino compatible
- 3.3V
Understands band switch for MHz displayed
Si5351 Oscillator
- I2C Interface
- 3 Outputs
  - Transmit frequency
  - Receiver frequency include offset plus RIT
  - BFO frequency
- Low pass filters to turn square waves to sine waves
- 27 MHz crystal

@@ Line 62: / Line 62: @@
 ** [https://kitsandparts.com Kits and Parts dot Com]
 * [https://kitsandparts.com/PCBs/LPF/filter2.pdf A short guide to harmonic filter for QRP transmitter output]
+== Schematic ==
+[[File:VFO-001-SCHEMATIC.PNG]]
 == Libraries ==