Just purchased one due to the price and the great reviews it has. Does anyone have any personal experience with one of these. What is the best call out of the 24 to use for coyote hunting in Madisonville area? Trying it out for the first time this weekend, waiting on it to arrive so I can play with it a little. TIA!!! Also, why would an SD card be needed for this call? Doesn't it have all the calls programmed already?