fortec 6 ft dish focal length

[wildboys]

Where do i measure the focal length on this dish. http://www.sadoun.com/Sat/Products/Fortec-Star/Dishes/FS6D-180-CM-C-Ku-Prime-Focus-Dish-Antenna.htm
I have a corotor II+ feedhorn and a norsat 8115 cband and norsat 4106a ku lnb.My f/D ratio is 0.38 which is marked on the feedhorn itself.The specs for the dish says focal length =682 mm which is 26.9" Do i measure this from the center of the dish to the scaler ring or to the front of the feedhorn?

 

[PSB]

http://www.satsig.net/focal-length-parabolic-dish.htm


Says here scaler ring, then watch the signal quality as you move the LNB closer or further away from the dish.........

 

[Mr Tony]

my C-Band LNBF is at 38 on the unit (so it sounds like yours). The LNB "eye" is about 3/4" farther in than the last scaler ring

Mine is a fixed dish at G4/G16

 

[Stats8]

On my Fortech 6" dish, the measurement from the base plate in the dish to the bottom edge of the scalar ring is 29".
The lnbf protrudes 1.5" out of the scalar ring.
That seems to work best for the signal.