The Si5351A VFO/Signal Generator kit provides two independent output freqeuncies, 3.3V peak-peak squarewave and in the range 3.5kHz to 200MHz (Si5351A datasheet spec). An extended range up to 292MHz has been experimentally measured. One output is variable and rotary encoder tuned, the other is fixed (configurable frequency).
The kit comprises:
- Main controller PCB with LCD module and all components
- Si5351A or OCXO/Si5351A (see note below) synthesiser module kit (Si5351A chip is pre-soldered at the factory)
- Rotary encoder and short length of 4-way ribbon cable to connect it (note: pictured plastic knob is NOT included)
The kits are easy to build, with through-hole components only (no surface mount soldering - the Si5351A chip is pre-soldered at the factory).
NOTE regarding the OCXO option: The VFO/Signal Generator kit INCLUDES the standard Si5351A module kit. Optionally you can also purchase the OCXO/Si5351A module kit, which is plug-in compatible with the VFO/Signal Generator. The OCXO/Si5351A kit has high frequency stability. However, the OCXO/Si5351A kit is more difficult to build and adjust than the other kits. If you want to build the OCXO kit, we recommend that you build the standard Si5351A kit first, and get everything working, THEN build the OCXO/Si5351A kit. In general the standard Si5351A module kit is good enough, particularly if you are using a GPS for frequency calibration and drift correction. You would only need the OCXO/Si5351A module kit if you want to operate in an environment with wildly changing temperatures, or you do not want to use GPS for drift correction, or if you have some particular requirement for extreme freuqency stability, or if you are a perfectionist or just want the challenge and interesting OCXO kit!
NOTE regarding TCXO option: The 25MHz TCXO option is another way to provide excellent frequency stability compared to the stock 27MHz crystal supplied. The Rev 3 PCB for the Si5351A Synth that will be supplied, is designed to accept the 25MHz TCXO module exactly and instructions are provided in its assembly manual.
NOTE regarding the GPS option: Connecting a GPS like the QRP Labs QLG2 kit is a very nice and inexpensive addition to the VFO/Signal Generator kit. The GPS provides the initial frequency calibration as well as regular drift correction.
A drilled, cut, silk-screen printed enclosure is available (click checkbox above when ordering), with an accessories kit containing connectors, buttons/switches, and mounting hardware. See the VFO/SigGen case page for details. Note that this enclosure is separately shipped via tracked China Post airmail from China where it is custom-made for QRP Labs. Requires additional hole in rear panel, for QLG2/QLG2-SE antenna coax, if the QLG2/QLG2-SE module is installed inside the enclosure.
A 20mm knob is available to suit the rotary encoder in this kit, please see the checkbox above or check http://shop.qrp-labs.com/knob
NOTE: 18-Dec-2021: The ATmega328 chip is now unobtainable at any distributors, due to the global semiconductor shortage. We have managed to obtain stock to be able to continue offering this item, however, the price was very high and this has necessitated a temporary price increase of $2.79 which is currently included in the price of this item.
VFO/Signal Generator kit
- Product Code: VFO
- Availability: 32