Single or Dual Frequency Transducers

[TTravis]

I am shopping for a GPS Sounder and am trying to educate myself so I can make a good decision. I am trying to figure out whether I need/want a single or dual frequency transducer but can't find a description of why dual is better than single. I am considering the Garmin 178 or 188 GPS Sounder. I have a small fishing boat and fish on inland lakes and rivers most of the time. My goal is to be able to follow underwater channels while trolling. If someone could explain the difference between single and dual frequecny transducers, I would apprecate.

 

[b.gagnon]

Re: Single or Dual Frequency Transducers

The dual can see wider in shallow water. Your typical dual frequency transducer can see 20deg and 60deg(give or take a few deg) which can allow you to see much more in less water.

 

[dingbat]

Re: Single or Dual Frequency Transducers

Unless your working in water greater than 600' I can't think of any reason why you would need anything other than a single frequency unit. <br /><br />A 50 kHz unit buys you increased depth capacity but at the expense of resolution. A 200 kHz transducer has 4 times the resolution of that of a 50 kHz. transducer. Where you might see something as small as ¼” with a 200 kHz unit, the 50 kHz, unit will only detector objects 1” or better.