Arkie mentioned Kerry Kristensen' upthread. That should be Kerry Christensen.   

http://www.kerrychristensen.com/about/index.html

Kerry is a present-day American who learned to yodel in Europe. He's great, and he does both Alpine and cowboy yodeling. His regular voice is warm and beautiful and his yodeling is fantastic. You can search for his name on YouTube and hear a number of his songs.

He sells a CD on how to yodel and freely admits that grandparents buy it for grandkids so as to get revenge on the hapless generation in-between.