yes i no what you are saying about the two different frequencys.i dont no how to copy the above pictures,but if you will look at them you will see that the structure in 800 is less visuable. to me they are for the most part pritty mutch useless,because they do not show all of the structure that is there.seeing the above pictures i would not feel comfortable useing the di by its self without 2d.the 800 is not showing all the structure in shallow or the deep water