Hi Rud. > The decoding delay is minimal and probably not even noticeable, even in chat > mode.
The decoding delay will not be an issue in chat mode. But it is annoying for someone interesting in DXes or just high rate of QSOs. It will take too long to just decode call sign during CQ to find out whether one is interested to make QSO. This is one of the reasons CW is so popular. Trained operator is able to decode call sign darn fast. I have to improve myself in CW reception. I was never able to cross the boundary of counting dots and dashes. > The delay in a chat is waiting for a buffer to fill so the FEC packet can be > constructed. In non-FEC mode characters are sent as typed. So for a 20 > character message it requires the time for 20 keystrokes, calculation of the > FEC and then the transmission of the 20 characters plus FEC characters. The delay depends on FEC and interleaving. > It might be interesting to try the following: .... > 6. After the FEC is received and decoded the receiver displays any corrected > characters in the appropriate place on the display. This was proposed by Phill Karn in MFSK16 list some months ago. You could do it if you do do not have interleaving and use systematic code. With modes like MFSK16 you may only slightly improve decoding delay by using shorter Viterbi decoder. But the delay caused by interleaving and convolutional code is not avoidable. 73, Vojtech OK1IAK
