I forgot that the compact transducer doesn't run 800khz, but I use 455khz 99% of the time so I suspect that as long as I dont try to run it at the higher frequency it will work. I wonder if I should switch the transducer selection to compact on the unit so I dont have the 800khz option. I doubt that there is a difference in the output to the transducer in 455khz, or a difference in how the unit would interpret the return between compact and HDSI selected.