I got my doppler in the mail today and cannot seem to find a heart beat. I'm not worried or anything. I'm 17w3d and have no problems thus far and at my last appointment it only took one try to find the heart beat. So I'm not worried about anything. I'm just wondering about others experiences with home doppler? Does it work better with a full bladder? Does it work better if I use the gel? Did I just buy a crappy doppler? Its facelake brand. 3mhz probe.