Humminbird 797 won't read in salt

[Sniper]

Hi all. Finally put my rig in the brine on the weekend for the first time since fitting the new 797 Humminbird a few months ago. Works great in the fresh but doesn't want to read consistantly in the salt. When I fist launched the boat, it didn't even show a reading of the bottom or depth. Finally picked up the bottom in 7 foot of water but the depth readout kept jumping from 7 to 13 to 9 to 16 and so on. Also lost bottom and readout when on the plain. Played around with transducer depth to a certain degree. Anyone had similar problems and if so who did you correct them.
Like I said earlier, works fine in the fresh but the salt doesn't like it. I did change the setting to salt as well.
Cheers

Bill

[Steven78]

Is there a setting for Fresh and salt as my 787 and 777 both have this setting

[Bradsmad]

Hi Sniper,

This seems to be a common problem with the birds in shallow salt water. I have a 747c & it does the same thing. It's fantastic in the fresh, but in shallow salt on a hard sand bottom it's a little erratic. It's caused by the signal being too strong & pinging back off the the surface of the water, then off the bottom again. The unit gets confused about which signal is correct ie. the first or the second, hence the erratic deoth reading. If backing off the sensitivity doesn't work, there is a menu function called "restore default settings" or something like this. Do this, then reintroduce your settings but keep the sensitivity down a bit. I found this improved mine, but it won't make it perfect. I also found that turning off the dual beam & only running 200khz improved it too, but ya seem to lose some it;s sounding capabilities when ya do this, that meaning ya get a better showing of whats down there with the dual beam on.

I don't fish the salt too often so it doesn't bother me, but yeah it can be frustrating in the salt. Play around with those settings & see how ya go. IMHO I just don't think these high power units are really designed for salt under 15ft or so. I've heard quite a few people with the same problem so it's just how they are.

Bradsmad

[kneebone]

I have same problem, also turn your noise filter up to max and set your bottom depth to about 20-39 ft depending where you are going

[Sniper]

Only run the back sounder on 200khz and had it set to salt. Tried reducing the sensativity and increased the noise filter. Works when it wants too. Loose signal when I get on the plain too. Last sounder I had fitted, Matrix 65 did the same thing too. Have tried raising and lovering the transducer and even moved it sideways incase there was disturbance from the hull.
Mainly fish fresh but do go in the salt and would like to know when I'm gonna hit bottom.
Will try setting max depth askneebone mentioned. Might solve the problem hopefully
Bill