Originally Posted by Ian M
Has anyone any views/experience of either of the above echosounders/fishfinders, apparently both new for '07? The difference seems to be that one is fixed frequency @ 2400W, whilst the 515 is dual frequency @ 4000W. Obviously the higher power unit is going to have a greater depth capability, and potentially better resolution, but is the difference really worth having? Does the collective (no apologies for the ST allusion) have any views before I speak to Silva, and get their sales pitch?
Lower frequency penetrates the water better (i.e. will give you returns at deeper depths.)
Higher frequency works better at shallower depths, giving a bit more detail, but does not penetrate as well.
For boaters and/or divers, a single freq (higher frequency) unit should do fine. Not too much worry about what's at the bottom if the water is 200' or 2000'. For fishermen, that's a different story.