"The Hidden Menu", courtesy of Robert Stephen, G0MYX

I had problems using the SG-239 Smartuner with the FT817 since the VSWR protection on this low power RIG is a bit aggressive, the cure is to access the "Hidden Menu", on the FT817, and adjust the HF1-RV to HF3-RV parameters (menu 62,63,64), mine were set to 8,11,21 after some experimenting these were set to 20,25, and 30. This allows more power to the load under load mismatch. These settings should be generally safe for use without the SG-239 Smartuner in circuit. This mismatch times with the SG-239 Smartuner in circuit are short so power dissipation is not a problem, but may need considering if the FT817 is to be operated into poorly matched load for extended periods.

The "Hidden Menu" is accessed by turning the rig off, hold down keys A, B, and C whilst turning the rig back on. To exit the menu hold down the F (function) key for a couple of seconds.