Sonar help

[HookNrelease]

Hi all, looking for some help on sonar, fishfinders. I have an old Humminbird DX200 mounted on the boat and it works fine, however i wanted to put a second unit on the dash as the older unit is mounted on the transom and hard to see some times. the humminbird is dual frequencie 83 khz and 200 khz and i was told that you cant run the same frequencies from seperate units at the same time as they will interfere with each other??? so does anyone know of any make or model of sonar that does not run on 83 or 200 khz? I cant find anything, there are dual frequency models from lowrance that are 50 & 200 khz so is there a lowrance that is single 50 khz?

 

Thanks again for any input or suggestions

 

cheers

 

ian

[Vanselena]

You can try a Si-Tex that runs at 120khz or a Furuno that runs at 50khz Si-Tex also makes a 50khz.

[Guest lundboy]

Looks like you will probably have to switch one off to use the other. I have a Humminbird WideVision. and a Lowrance LMS332C. I can use them both at the same time, but the 332C gets a stray ping from the Humminbird about every 1/4 of an inch. Both transducers are mounted on the transom. The Huminbird has 3 elements, one down facing is 200kHz, the sides are 455kHz. I usually have it in the 455kHz mode and I still get the occasional glitch on the 332c as noted above.

 

The problem with 50kHz is that Lowrance only recommends it for salt water or very deep water (>300').

 

The other problem is a lot of manufacturers have standardized on "Universal Sonar" which pretty well is designed around 200kHz.

 

So switch off and on what you need when you need it. Then you can choose whatever unit you like.

Edited February 1, 2008 by lundboy

[HookNrelease]

Thanks Vanselena the si-tex looks like it may be the answer, appreciate the info guys

[Vanselena]

Looks like you will probably have to switch one off to use the other. I have a Humminbird WideVision. and a Lowrance LMS332C. I can use them both at the same time, but the 332C gets a stray ping from the Humminbird about every 1/4 of an inch. Both transducers are mounted on the transom. The Huminbird has 3 elements, one down facing is 200kHz, the sides are 455kHz. I usually have it in the 455kHz mode and I still get the occasional glitch on the 332c as noted above.

 

The problem with 50kHz is that Lowrance only recommends it for salt water or very deep water (>300').

 

The other problem is a lot of manufacturers have standardized on "Universal Sonar" which pretty well is designed around 200kHz.

 

So switch off and on what you need when you need it. Then you can choose whatever unit you like.

 

Lundboy the problem with running a 200khz and a 455khz at the same time is the harmonics are not far apart and that is why you are getting a stray glitch.

 

Lowrance is dead wrong when they only recommend 50khz for salt water or very deep water. Although Salt water has a higher density then fresh water it won't make a huge impact on the sonar aside from messing with the settings on the sonar unit, that being said frequency wouldn't make any difference. A 50khz frequency produces a wave with 1/4 the peaks of a 200khz frequency and therefor the sound travels further but with less frequency. When I am fishing any lake deeper then 50fow I prefer 50khz since the soundwave will penetrate further into an object and will therefor show the airbladder of the fish. Once you start to recognize your target fishs airbladder then it makes species fishing much easier. You may want to note that most commercial boats fishing on Lake Erie use 50khz sonar units for this very reason.

 

It seems that Lowrance and Humminbird ( the largest manufacturers in the recreational side of fishing) have settled into the 200khz frequency but the higher end units tend to offer very little in this frequency at this time, although one of the other majors may move into this area very soon.

 

It is worth noting that the ideal sonar frequency is not 200khz but 200khz is a good frequency for many fishing applications.