LCG's Operation w/o finding the bottom

[Stormsearch]

I know years ago that when the hot new Liquid Crystal Graphs came out to replace the paper graphs they didn't work unless they could find bottom. I have seen this happen, especially fishing in deep water (300+) on Lake Michigan for Steelhead. After people lost bottom, the LCG's stopped working correctly.

Question is, are the new graphs prone to the same problem? I am guessing that is why Lowrance came out with the X-15MT with dual frequency (50/200) in the 500/1KW RMS power ranges to help track the bottom. Any thoughts? Thanks.

[ebijack]

power requirements to reach (send/recieve)over 300ft takes more than 600 watts (if you look at eagle units which don't have the power of lowrance) you can read in the advertisements which ones will work in deeper water than 300ft. the transducers do play a part in detail etc, from 8khz to 200khz as fas as cone angle/detail etc. i believe it's a 3ft circle (cone angle) for every 10ft of depth with a 197/200 khz tansducer. at 300ft a 200khz transducer wouldn't do you much good. hope that simple explaination helps.

[Stormsearch]

ebijack,

Thanks for the reply. Can I assume the 600 Watt power is RMS and not peak - peak? I am not too concerned about reading detail on the bottom as much as making sure the newer LCG's work when they can't read bottom. Older LCG's required to read bottom otherwise they didn't work. When we fish for steelhead in Lake Michigan, usually we are more than 300+ ft and that seemed to be the limit. We did have 50KHz transducers with wide cone angles that were advertised for deep water, but I don't think that the older units had the power.

Obviously, when we hit Lake Erie, the 200KHz puck with the smaller cone angle came into play.

The newer X-15MT has a dual skimmer that can operate at 50KHz at 8000 watts pk - pk, approaching the high powered CRT's. Thanks for the info.