[TowerTalk] adding 30 mtr to 40 yagi

[steve sala K7AWB]

I have a Hy-gain Discover 7-2 40-meter, 2-element Yagi that I want to side mount with a rotator on my Rohn 45 tower.  I will use a XII side mount.
I would like to add 30 meter elements to the 40-meter antenna to give me 2 or more elements on 30 also.  No problem using two coax cables if necessary.
Has anyone done this to this particular antenna?  Does anyone know of an article that shows how to do it?
73
Steve K7AWB
Nine Mile Falls, WA