22. If you have GeoClock installed on your PC, you probably use it to watch the day-night terminator as it approaches your station. This is particularly useful during contests, when the higher-frequency bands often open at the onset of the daylight hours. ACE-HF and GeoClock can be used together so you can watch the Open Bands Boxes and the circuit prediction charts while you keep an eye on the GeoClock terminator display. One handy screen arrangement is to call GeoClock from the ACE-HF Circuit Analysis screen, and then use the GeoClock Window Controls to reduce its window size. Put GeoClock in the upper-left corner of the screen. If you have called the ACE-HF SNR Summary Chart, you can now watch the summary predictions -- and even the ID timer if you have started it -- as well as the Main Chart predictions while you note the terminator's passage in the GeoClock window.