To determine the required offset first tune both the transmit and any receive flradio to the same signal. Then enter the wf offset (bottom center of display) of the transmit flradio and the receive flradio into the XmitOS tab at bottom of flrig:

Click on 'Set Hydra Xmit Offset' and the offset will be calculated and placed into the flrig prefs file:

The calculated "Ppm Offset" is shown in the rightmost box. You should copy/paste this value into the HpSdrCfg tab of flradio:

When using flradio with direct rig control via GhpCAT control, the value in the flradio config file is used, while when using XMPRPC control via flrig the flrig value is used.

You will notice that there is a slider in the middle of flrig labeled "Adjust Offset". This fine tunes the ppm offset in units of 1 Hz. During the day, as temperatures rise/fall, the offset will change. Using this slider eliminates the need to recalculate the ppm offset. I heat the house with wood, so it's not unusual for the shack temp to vary between 55F and 70F, depending of how frequently I feed the fireplace. My offset can vary by +-20 Hz in one afternoon!