This kit is a simple minimalist controller for the Si5351A Synth kit (included with the ProgRock kit). It is intended as a programmable crystal replacement. It has three independent outputs with frequency range 3.5kHz to approx 300MHz, and can be optionally GPS disciplined.

Shop order

The features of this kit are as follows:

  • Includes Si5351A Synth kit AND "ProgRock" PCB kit
  • Easy construction, no surface-mount components to solder (Si5351A already pre-soldered)
  • 3 independent 3.3V p-p squarewave outputs (2 if you use GPS discipline)
  • You can feed the outputs through LPF kits to get sinewave outputs
  • 8 selectable “banks” of frequencies, chosen by 3 input control signals
  • Frequency range 3.5kHz to 200MHz
  • Extended frequency range up to approx. 300MHz if you don’t mind violating the Si5351A datasheet specifications
  • Quadrature output mode (Clk0 and Clk1 on same frequency but configurable 0, 90, 180 or 270-degree phase offset)
  • GPS frequency discipline using 1pps from a GPS receiver
  • Unique power supply noise filter circuit designed by Alan Gray G8LCO
  • Power supply voltage 5V, or using LM317LZ regulator (supplied), range is 5-12V DC
  • Minimalist configuration user interface using 4-way DIP switch, push button, and LED
  • Optional serial port configuration (requires firmware pr1.01 and above)
  • Frequencies and configuration stored in non-volatilte memory (EEPROM) for next power-up

Documents and resources

Assembly instructions ProgRock kit: A4 format or Letter format
Operating manuals pr1.02 firmware Operating Manual: A4 format or Letter format
pr1.01a firmware Operating Manual: A4 format or Letter format
pr1.01 firmware Operating Manual: A4 format or Letter format
pr1.00 firmware Operating Manual: A4 format or Letter format
r1.00a firmware Operating Manual: FRENCH TRANSLATION
Si5351A Synth kit manual Si5351A Assembly: download here!

Many thanks to Gilles F1BFU for the French translation.

Version history

Version Date Features
pr1.02 10.Oct.2018 - Quadrature LO mode: Clk0/1 configurable with the same frequency but 0, 90, 180 or 270-degree phase offset
pr1.01a 22.Mar.2017 - Bug fix to pr1.01, there was an initialisation problem so it started up at 27MHz output
pr1.01 06.Mar.2017 - Added serial interface configuration option
- Changed Si5351A Code to all integer arithmetic - faster, smaller, more accurate
- In DIP switch configuration, LED flashes 4 times to indicate a button press is registered
pr1.00 20.Apr.2016 - Original kit firmware version


Kit photographs

Regulated Si5351A supply voltage a little high

Nick KG5N measured a regulated filtered supply voltage of 3.61V which is a little high, and 5.08V at the LM317LZ 5V regulator output. Lowering R5 to 36K resulted in 3.55V and using 33K resulted in 3.43V. Other people have also reported similar results.

Practically speaking, we have not heard of the Si5351A being damaged by this supply voltage although technically marginally out of spec; but if this worries you, then you could use a 33K resistor for R5 instead of the supplied 39K, as Nick KG5N has done. 


If you have completed a project using ProgRock and have information on it, please send it in - it will be interesting to other readers and constructors, to list them here. 

Using the QRP Labs "SoftRock" as a possible crystal replacement in "rock bound" VHF and UHF radios - detailed article by Clint KA7OEI, using the GE Mastr II as a case study.

ProgRock as Yaesu FT-707 VFO

Michael KG7M writes:

"It is brilliant! I just finished restoring a older Yaesu FT-707. They drift like crazy. I wanted to use it for FT8, bit you can see the drift in my photo. The SOLID line is it running on the Prog-Rock. Like many Transceivers, the FT-757 runs on crystals for fixed frequency use. So I programmed the Prog-Rock and built a cabinet for it. It controls the FT-757 on all HF FT8 frequencies. You can see my review on eHam. I mention your Prog-Rock Kit. I will be doing more reviews and a YouTube Video about the Prog-Rock Kit. I can hardly wait for the Prog-Rock 2 Kit. These kits are marvelous Hans. Thank you so much for producing them."