Beacon

This is an early design sketch of a 2m WSPR beacon. Key Points 25 MHz HCI 0.5ppm TCXO powering the Si5351 module instead of the 26 MHz TCXO. If this fails, we can use a 10 MHz OCXO instead (a bit out of spec but works fine). Tokmas CID10N65F GaN FET might work @ 144 MHz as the 'final'. If not, use Mitsubishi RD15HVF1-501 MOSFET as backup. 2SK3475 as the driver with variable DC bias at the gate The whole VCC to this amplifier will be PTT switched Ideally, we would want to keep the driver stage linear but the final stage as switched (Class C/D) Alternate: Perhaps by DC coupling the Si5351 input to 2SK3475, we can avoid the need for DC gate bias The "RFC" (bifilar coil still needed?) part will need to be figured out for VHF! Status Results: To be built and tested soon! ...

This is an early design sketch of a 6m WSPR beacon. Key Points 25 MHz HCI 0.5ppm TCXO powering the Si5351 module instead of the 26 MHz TCXO. If this fails, we can use a 10 MHz OCXO instead (a bit out of spec but works fine). Tokmas CID10N65F GaN FET should work @ 50 MHz TI UCC27614 or Onsemi NCP81074 gate driver Status Results: To be built and tested soon! ...

This ~1W to ~5W WSPR beacon runs continuously on the 10m band. It handles extreme environmental temperatures pretty well (it is 42°C plus here). Our article on this beacon's design and operation will appear in the May/June 2025 issue of the QEX magazine soon. References WSPR TX by G0UPL QEX May-June 2025 TOC ...

I have designed, built, and tested an all-HF WSPR beacon that produces 1W @ 5V and is rugged and cost-effective. Results Power consumption: Around 420mA @ 5V. Cost Cost: Around 500 INR. Time to build Time to build: Less than 30 minutes. Files The files for this project are published here for personal (non-commercial) use. For a 5W (QRO) WSPR beacon, please stay tuned for our upcoming QEX magazine article ;) ...

I have built what is probably the easiest, reasonably rugged, and most cost-effective 100mW WSPR (or FT8) beacon. The Build Here is my quick and dirty build with whatever I had lying around: We replaced the traditional expensive Mini-Circuits transformer with a cost-effective Bourns coupled inductor. Analysis Power consumption: Before RF generation starts ➔ 20mA @ 5V. After RF generation starts ➔ 52mA @ 5V. So the input power consumed in the RF generation process is more than 150mW (which is good). ...

I am building an easy-to-use, cost-effective WSPR pHAT for Raspberry Pi Zero 2 W. Design 3D render: We replaced the traditional expensive Mini-Circuits transformer with a cost-effective Bourns coupled inductor. Status Results: To be built and tested soon! Time to build: Less than 20 minutes

Sometimes we all need a bit of QRO - Life's too short for QRP sometimes. So we give you the Baby-QRO switching amplifier! This Baby-QRO switching RF amplifier design is inspired by the wonderful Single NXP MRF-101 Eval Board project by Jim Veatch. Thank you Jim! Instead of using the expensive MRF101 MOSFET, we use fast SiC MOSFET(s) from Wolfspeed / SUPSiC. Design 3D render: Actual picture: ...