Before using the Panadapter with any of the compatible radios:

Icom 7300: (Connected with only the USB cable from radio to computer)

First open the radio's menus and locate the following menu options

"CI-V USB Port (Default: Link to [REMOTE])" Set this option to "UNLINKED"
"CI-V USB Baud Rate (Default: Auto) Set this option to 115200

When you start the HRD software and the Rig Connect screen opens, make sure you set the "SPEED" selection to 115200 and click [Connect]

When Rig Control opens, on top menu, click on "Tools" and select the Panadapter (Main or Sub)