Refueler
Well-Known Member
Now please real actual what you found with your Echo-Sounder calibration ...
calibration possibility of your Echo-Sounder
- Thread starter Refueler
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TamarMike
Well-Known Member
Good question, should clarify results of that other poll 
Refueler
Well-Known Member
You see I happen to know some who say that they can calibrate + and - ... but in fact haven't checked ! I know their units don't do + ! 
Terrible ! So I thought to ask for reality - IF that's possible on here !!
Terrible ! So I thought to ask for reality - IF that's possible on here !!
Danny Jo
Well-Known Member
21-year-old B&G instruments. Instrument set to read to water depth when I bought her. I have played with increasing and decreasing water depth. The book of words says I could set it to depth under keel (I think), and I would be very surprised if I could not, but I have no inclination to do so.
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srm
Well-Known Member
Surely you mean simply adjusting the zero level to read from say the waterline or under the keel.
Calibrating an echo requires adjustment of the transmission rate to correct for actual speed of sound in water, and could be done on sophisticated paper trace sets used for survey by altering stylus motor speed. We all have depth errors due to variations in speed of sound which mainly varies with temperature and density. These will be worse when navigating in esturies and rivers where there is a mix of fresh and salt water.
The good news is that the echo sounder is always at its most accurate just as you keel makes contact with the bottom.
Calibrating an echo requires adjustment of the transmission rate to correct for actual speed of sound in water, and could be done on sophisticated paper trace sets used for survey by altering stylus motor speed. We all have depth errors due to variations in speed of sound which mainly varies with temperature and density. These will be worse when navigating in esturies and rivers where there is a mix of fresh and salt water.
The good news is that the echo sounder is always at its most accurate just as you keel makes contact with the bottom.
Refueler
Well-Known Member
interesting ... now with it added to other poll and also thread .. we start to get a better picture of options and what people do.
My main point was to get people to actually look at their sounders to see what they can do - instead of just assuming they can claibrate up or down. Many older sounders like my Echopilot cannot be referenced to waterline ... only have capability to under transducer or from keel bottom. If you take the LED flashers - there are few that can be calibrated anyway ... so really we are talking modern digital display jobs.
My main point was to get people to actually look at their sounders to see what they can do - instead of just assuming they can claibrate up or down. Many older sounders like my Echopilot cannot be referenced to waterline ... only have capability to under transducer or from keel bottom. If you take the LED flashers - there are few that can be calibrated anyway ... so really we are talking modern digital display jobs.
