Topic: Depth reading off alot

[rwkamx]

I was in 5.5 feet anchored and looked at the HB and it is reading 21 ft this has happened twice..... restored to factory default and still same measurements...... turned on and off same false reading ...
  then it changed on its own to the correct depth...Anyone have a clue about this problem??? Thanks!!!!!!!!

[rnvinc]

Did it show a consistant 21ft depth over time or just a few seconds at the incorrect depth...??

Several things can cause an intermitant incorrect depth...water turbulence, algae bloom, un level xducer, floating debris on xducer...etc....

Check the xducer for abnormalities..

Also, If you suspect particulate in the water, you can increase the surface clutter setting to help filter this out...

Rickie

[Humminbird_Greg]

I would also make sure that there was not another sonar unit on at the same time as the cause could be sonar interference causing this (turning on and up the Noise Filter menu can help this).

Where is the transducer(s) mounted?
Are you suing only the HDSi transducer or a two transducer system?

[ITGEEK]

Interference can cause erratic depth readings.
If this happens again, turn off everything on the
boat except the sonar in question, and see if it clears up.

Also, I have to ask:
Is it possible you were anchored on a ledge, or on the outside of
a hole, where your anchor was in 5.5 feet of water, but the transducer was
looking down over the ledge or into the hole?