JS8In the HamQSO filter: Digital
JS8: what it is and where to find it on the bands
JS8: free-text conversations built on the FT8 signal, with store-and-forward messaging.
JS8 uses the same modulation as FT8 but lets you type free messages, chained across several periods. It adds heartbeats, relays and messages left for stations that are not on the air.
It sits near the FT8 dial frequencies on most HF bands.
JS8 is popular with portable and emergency-communication operators, because it keeps working on weak signals.