I have used the same one for nearly a decade. It’s so old it doesn’t give me an accurate number for the HB. I have found the HB around 8 weeks several times so you will probably be good to start using it. Just start in the center and move outward slowly. Start a little lower than halfway between the belly button and the pubic bone. If you hear a slow HB it’s yours. It should sound super fast and very distinct from your own HB. Take your time and don’t worry if it takes you a few times to find it. Just be patient and move out slowly from the center.
Re: Home Doppler