uSDX tips

Power usage

Around ~500mA in TX. Works with 3S 18650, power output dependent of battery voltage, makes around 4 to 5W in WSPR with 11.8V.

With 3S 18650, unknown capacity, WSPR 40% TX ratio runs for around 3h.

CAT mode

Only available with OLED IO Board.

Firmware needs the following:

#define CAT              1   // CAT-interface


//#define CAT_EXT        1   // Extended CAT support: remote button and screen control commands over CAT
//#define CAT_STREAMING  1   // Extended CAT support: audio streaming over CAT, once enabled and triggered with CAT cmd, samplerate 7812Hz, 8-bit unsigned audio is sent over UART. The ";" is omited in the data-stream, and only sent to indicate the beginning and end of a CAT cmd.


  • GND/RX/TX to an USB FTDI
  • Audio OUT (mono) to USB sound card
  • Mic/Key to USB sound card: T(ip)=Key, R(ing)=Mic, S(leeve)=GND, so connect Ring and Sleeve to the soundcard
  • PTT is handled by CAT, nothing specific here

Generic settings

  • TS-480
  • 38400 bps
  • 8n1
  • NO Handshake, so NO RTS and DTR (force them low if possible)
  • Polling 200ms
  • Timeout 4000ms


  • TS-480HX
  • same generic settings
  • Uncheck RTS/CTS
  • In PTT-Generic check PTT via CAT


  • Not using flrig, directly controlling the CAT interface
  • RIG: Kenwood TS-480
  • Same generic settings
  • PTT Method: CAT
  • Mode: Data/Pkt
  • Split operation: none


  • Rig: FLRig FLRig
  • Network server:
  • PTT Method: CAT
  • Mode: None (any other mode will let the PTT stuck in transmit)
  • Split operation: None