Want to get pregnant

Can you get pregnant on 7.5%? Before ovulation? I read sperm lasts in the female for 5 days. So we’re trying to get pregnant, and he’s stationed in the Navy states away from me and we rarely can see each other but every 2 months until he is moved to China which might be this year. So I see him next month for only 2 days, and than that is 2 days before I start ovulating. We always do it from the back doggy style and when I’m laying on my side. So I’m really trying for another one I had a miscarriage last year in January and was 16 weeks. I read a couple of post on here saying people try for years but he’s going to be in for a while and I’m trying to do it every time I see him. Help please.