D4D: Why LSB is not that problematic to PSK mode

Adam Rong


I just read a post from an angry Japanese PSK mode operator:,,,20,0,0,0::recentpostdate%2Fsticky,,,20,2,0,32465355

I don't think D4D is that problematic and people don't have to worry too much. The PSK31 decoding capability is about -7dB SNR, so if you use QRPp power level, you will less likely to achieve successful QSO, which means it won't cause effective interference. The problem arises when D4D transmission is nearby to the PSK operator. However, I think people won't use D4D as a daily transceiver for FT8. The most common user scenario is we use it as field operation. Anyway, D4D is a very simple radio and it has unwanted side band and IMD products. If your neighbor hams knock your door, just stop transmission and use it in the field with a portable computer or a raspberry pi instead.