Using a Raspberry Pi hardware/software interface connected to an Elecraft K3S rig, this video live demo's how it works to use the RazPi remote config to connect to the K3S over a remote ip location from another computer in real time... and receive and transmit cw and ssb.(i was able to qso cw with W8ACM for this demo)
Basic Setup for the K3S PI (pi shown in video is a pi2b)
1. Vnc server on the pi - activated
2. USB CABLE from the K3's own sound card - plugs into the PI2b
3. audio output of the pi's own analogue sound card is used to
"key" 2 separate audio derived cw keying circuits...one to activate the k3s PTT JACK, and the other to activate the k3s CW KEYING JACK. The left channel of the pi's native sound card goes to the CW KEYING JACK 's keying circuit, and the right channel of the pi's native sound card goes to the PTT keying circuit. see this article for more info regarding audio derived cw keying circuits:
The PI in order to SEND and RECEIVE audio to the remote computer, uses JackTrip. JackTrip is a very low latency, audio over ip app.
The Pi, for Audio, is first setup as a JackTrip server...
The Pi, for controlling the frequency and mode of the K3S uses vnc remote and Grig. G-rig is a native LINUX app that works with the K3S to control the freq and mode(shown in the video) The vnc remote allows controlling the PI DESKTOP from any other location over ip.
On the remote computer, VNCviewer is first started and connects to the pi desktop. Then on the remote computer JackTrip is started as a client to connect to the Pi's JackTrip server....then using VNC remote the JackTrip connections can be properly wired to transmit to and receive from the K3S audio(via JackTrip)
ALSO, voice can be transmitted over JackTrip for a SSB qso.
on the remote computer, a MIC is used and processed for automatic gain and NOISE GATING...then when speaking, it travels from the remote computer to the pi over ip(LAN or WAN) The K3S vox for ssb is enabled and the mic volume, being already adjusted for best volume levels to the K3S(usb sound card input) goes into the pi's audio engine(jack audio connection kit) and then is wired directly to the K3S USB SOUND CARD's LINE INPUT.