QSSTV  9.4
Mode Settings for DRM

Settings for HF and VHF/UHF are very different.

General rules of thumb:
Mode A: most demanding, used on VHF/UHF
Mode B: use on HF/VHF/UHF
MODE E: least demanding, used on HF

QAM 64 : most demanding, used on VHF/UHF in really good conditions
QAM 16 : used on VHF/UHF in fairly good conditions sometime also on HF
QAM 4 : least demanding, used on HF


  • 2.5 kHz: VHF/UHF
  • 2.2 kHz; HF


  • Depends on the conditions, leave it on High


  • leave it on Long on all bands

Reed-Solomon provides Forward Error Correction by adding redundant bytes per block of 255 bytes.
More errors can be corrected when more redundant bytes are used.
This adds overhead to the transmission.

  • RS1 increased by 13%
  • RS2 increased by 33% most often used
  • RS3 increased by 60%
  • RS4 increased by 99%

Always use Reed-Solomon encoding on HF bands.