Working on optimizing my FT8 setup and wondering about interface modifications beyond the basic USB sound card approach. Currently using a SignaLink USB but getting occasional decode issues during heavy band activity.

Considering either the Digimaster interface or building a custom isolation transformer setup to eliminate ground loops. Also interested in any mods to improve the audio response curve - seems like the factory response rolls off around 2.8kHz which might be impacting weak signal copy.

Anyone experimented with different op-amp configurations in their interface circuits? Looking for that extra 2-3dB improvement in SNR for those marginal FT8 contacts.

I built a custom interface using an AD797 op-amp with a flat response to 4kHz and saw noticeable improvement in decode percentage. The key is maintaining phase linearity across the FT8 bandwidth - cheap op-amps introduce group delay that hurts weak signal performance.

Have you tried adjusting the WSJT-X audio levels? I found that keeping the input around -20dB prevents overload during strong signal periods. Also enable the "Deep" decoding option - it really helps with marginal signals even though it uses more CPU.

Ground loops are definitely your enemy with FT8. I used an ISO-MAX transformer (1:1 600 ohm) on both TX and RX audio paths and it cleaned up my spectrum considerably. Worth the $30 investment compared to dealing with hash from the computer switching supplies.