You do not need pectin for raspberry jam at all. I just measure the berries and add 3/4 as much sugar. I used to use equal amounts of sugar, but found it works with less.
If you are adding cranberries to the jam you do not need pectin at all. Cranberries are full of pectin, which is why homemade cranberry sauce thickens up so nicely (2 cups cranberries, 1 cup water and 1 cup sugar, boil until the cranberries pop).