As you improve you work further and further from your dog and voice commands become problematic. Here is a video I made so I could learn to whistle.
I sent the video I made for myself toÂ TerryÂ my instructor so she could post it on her site if she wished. When I saw her the next time she told me it was on YouTube. Here it is below if you are interested.
UPDATE: The dog used in the video is now with me!