WSPR-beacon 1.0

A small hardware device for transmitting WSPR messages based on the SI5351 IC. The device has a built-in TCXO to eliminate SI5351 frequency drift, a built-in GPS module for operation with active GPS antennas, transmission time synchronization and automatic QTH locator calculation, and a simple amplifier based on a single BS170 transistor (PCB version 1.0). PCB is made on based on SMD components and adapted for installation in an aluminum enclosure with dimensions 80 x 50 x 20 mm.

Device characteristics

Platform: ATmega328P MCU
Power amplifier: Transistor amplifier, based on BS170
Output RF transformer: Bifilar transformer based on an FT37-43 core
RF connectors: SMA
Feed line: 50 Ohm coaxial cable
GPS antenna type: Active, external
Maximum output power: ~23 dBm
Supply voltage: 5V (USB-B, fuse-protected, 600 mA fuse)
Current consumption:
Standby (GPS antenna not connected): 70 mA
Standby (GPS antenna connected): 86 mA
Active TX mode (PA bias 2.5V): 107 mA
Active TX mode (PA bias 4.6V): 224 mA

Firmware info

Latest firmware version: wspr-beacon-1.1
Supported transmission protocols: WSPR
Configurable via user application: No