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| I have two (900 & 700) on a interlink system, sonar readings are going crazy....can it be corrected....or do I buy a different bow mount unit. Hummingbird was not helpful....She said to turn off one unit. Da....I use both of them at the same.....I did try to adjust each unit....one up the other down....both down...with no help.....Any suggestions.....thanks |
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Posts: 307
| Need more info. Seperate transducers? Locations? Universal sonar? Seperate transducer mounted on bottom of trolling motor?brand of trolling otor? |
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Posts: 2753
Location: Mauston, Wisconsin | Duh, this post sounds funny, you don't really say which exact models you have, 900 & 700 are product series designations, not actual product model numbers. I find it hard to believe Humminbird tech support would treat you that way.
If this is a serious post & not just some anon-Lowrance dweeb trying to stir the pot! Here's some thoughts> How do they work if you disable the inter-link? You also don't say which transducers you have on each. Are they mounted properly so the beams aren't intersecting. They have to absolutely flat with respect to the water and each other - the same horizontal plane - parallel to the water surface. Most guys install/line up the transducers with the hull bottom and the boat on the trailer, if your boat sits nose up in the water, the rear transducer may be shooting slightly forward, etc. Pay attention to the attitude of the boat when its happening. Does it only happen when you are on the bow - the front TD may be shooting slightly to the rear? Is the TM installed so its shaft is 90 deg to the water surface and the TD parallel. Does it only happen when the TM is pointed in a certain direction? Does it only happen in choppy water? Does it only happen in deeper water? There are quite as few settings that can impact this issue. What do you mean by up & down? What setting? Try the Humminbird website- there are some video tutorial's on setting up the units. If nothing works, try tech support again. If that doesn't work, try this website ->
http://www.xumba.scholleco.com/index.php?sid=6aa82cacdd7c520045a0c8...
Good luck!
Al |
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| I'm sorry I didn't have the unit # when I posted...they are 997c si & 778c Hummingbird sonar units...the 997 has the down img, when I had a Bottomline sonar on the bow I had no problem....I liked seeing large numbers up front, while watching GPS on the 997..when I replaced the bottom-line with the 778..the depth numbers went wild.....I do have two transducers mounted on transom, about 15" apart...the up and down was the settings for sensitivity...I was not able to fix the problem Do you think a different Hummingbird unit might work...or not using the interlink connection....Thanks for info.. |
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Posts: 2753
Location: Mauston, Wisconsin | Given the transducers are that close to each other. Check the sonar frequency on both units. If the two frequencies are identical or if you can divide the lower frequency into the higher and the result is an even number, you could have what we electronics engineers know as a fundamental frequency or a harmonic frequency interference problem. I think the problem is the frequency setting on both units - try setting the 778c to 83kHZ and the 997c SI down transducer signal to 200kHZ......
Watch the tutorials on the Humminbird website.
Good luck1
Al |
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