RF Gain and Audio levels for SuperFox FT8

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Efforts were made to control HF conditions and ensure repeatable decodes and single-variable tests to challenge the decoder. However, the WSJT-X team has not yet validated this so YMMV.

If you are chasing a SuperFox FT8 station, and not decoding them as expected, check for the following to improve your ability to decode them:

  • You don't need to see the SuperFox's signal in the radio's waterfall or WSJT-X. Signals weaker than 1 dBm, can still be decoded between -16 and -4 SNR without showing up visually in the waterfall.
  • Avoid using RF gain as a volume control into WSJT-X.
  • Turn AGC OFF (it’s not suitable for digital modes). If you've been using AGC FAST for FT8 to handle loud local stations without problems, it likely won't work as well with SuperFox FT8.
  • Keep the audio input level in WSJT between 40 and 50 dB. Increase the gain in the receiver until you reach at least 40 dB, then lower the audio level to stay under 50 dB when you expect the SuperFox FT8 station to transmit (even cycle).
  • Control the volume of the audio sent to WSJT from the radio if possible.

If you are using an IC-7300, use the ACC/USB IF Output level (default is 50) to control the audio level sent to your computer (IC-7300 full manual, page 12-7).

For Flex 6400 radios, try AGC OFF, adjust RF gain as high as ~80% (+32 antenna gain if needed) or until audio level is above 40dB in WSJT-X, then reduce audio level in DAX to ~7%.