Doppler's are curious creatures. As anything out there, there are good ones and bad ones. I sell medical equipment for a living, so I have seen first hand the frustrations when this technology fails. As with anything, sometimes trying to have too much information can be more filled with danger than just letting things flow. I understand you want one, but, the risk of becomming 'addicted' and the stress that may be caused if you don't get a clear result could be extremely stressful to you, even when you don't have any reason to worry. If you go down this road, be sure to keep an open mind, and remember techology can be unreliable.

Just my two cents worth.