Finally got around to reading the article.
The only thing I 'd like to add is that you should begin the call with the horn facing downward at about 30 -45 degree angle, moving it in a semi circle and ending horizontically or slightly higher, without breaking the call.
The "grunt" should be slightly downward or horizontal.

Another awesome article thanks mod and thanks george

...I call many times without the grunt, and yes i start with the horn from the ground more or less between the knee's and move up slowly in a waving pattern don't try to be too loud at first as the bull may already be close by i usually call on the ground with the shooter in the stand the first time i went to bc i called for a couple of hunters that had never used calling as a means of moose hunting and were a bit skeptic , i called in the early evening on a small knowl overlooking a pond withen 10 minutes a young bull came crashing out into the water not 5 minutes later another bigger bull came out a hundred yards or so from him we got both of them , needless to say the became firm belivers lol

Im going out in the morning Hopefully I can call out momma and some calfs.