posted 05-31-2006 09:29 PM ET (US)
This is a very broad basis for discussion. Let's look at the many technologies used in these devices:GPS receivers: I am not aware of much recent development in these devices. They have become quite a commodity item. Most receivers now are able to acquire and use multiple satellites and have augmentation in their precision via use of WAAS or Differential GPS.
What type of receiver does the GARMIN 178c have? How many satellites can it receive and use to deduce a position simultaneously? Does it use WAAS or DGPS?
SONAR: There are many new digital sonar processors available now which claim to have improved capabilities.
What type of SONAR does the GARMINS 178c have? Is it an analogue type demodulator system? What frequency is the transducer? What power? This information will help us make a comparison.
Chart Plotter and cartography: There has been a very significant sea change in this area. The U.S. Government has made available FREE DIGITAL CHARTS of coastal regions. This makes use of this type of cartography very compelling. It should also have a significant impact on the market price for competing cartography.
What type of cartography does the GARMIN 178c use?
Daylight Viewable Color Displays: there has been some significant improvement in these lately, but the prices are still high.
How big is the display of the GARMIN 178c? How many pixels?
Another area you have not mentioned is the ability of the device to network with other vessel electronics. The new standard is NMEA-2000.
What type of network connection does the GARMIN 178c have?
If you could supply this information, it would facilitate making a comparison of the GARMIN 178c with other choices.