Autotuner

The following topics describe aspects of HomSoft operation related to the Homer Autotuner as an enhancement to the Homer Analyzer alone. The Autotuner is an intelligent system combining the Homer Analyzer and Homer Mototuner (Tuner). The Tuner is a motorized three‑stub high-power impedance transformer, consisting essentially of a waveguide section with three stepper motor-driven metallic posts (tuning stubs) inserted into the waveguide at mutual distances of nominally one quarter of the guide wavelength. This arrangement facilitates impedance matching of loads with arbitrary reflection coefficient phases and, depending on construction and maximum power, with VSWR typically up to 10:1.

Functions related to Tuner operation are grouped in the Tuner menu.

The terms stub positions/movements will be used equivalently with the terms motor positions/movements.

Most Homer implementations have the ALL STUBS HOME and AUTOTUNE switches physically present on the hardware. The water-cooled 2.45 GHz Autotuner has the AUTOTUNE switch accessible via Remote Connector (Action Switch or Action Pulse inputs). The ALL STUBS HOME switch triggers the motor initialization routine; the AUTOTUNE switch activates and deactivates automatic impedance matching (autotuning). These actions can also be triggered by software commands. Optionally, the AUTOTUNE switch can be assigned a different action, as specified by the "AtSwitchAction" line of the internal Tun.cfg configuration file.

Controlling the Autotuner

When starting HomSoft for the Autotuner, the following additional features appear compared to the Homer Analyzer:

  • New menu item, named Tuner, appears on the main menu bar.

  • A button with Tuner icon Tuner appears on the Standard toolbar (Fig. 15).

  • The System Info window contains new pages related to the Autotuner.

  • Additional windows can be opened:

  • Tuner View window (shows the Tuner image and enables Autotuner control via mouse clicks and drags).

  • Scenario window (enables stubs to be moved in a predesigned position-vs-time manner).