Field-test

[Tod]

As you can see, I hacked a fish together in about 2 hours in my basement (not my shop). It took many hours to tune the fishfinder to my ducer. I used a 55 gallon drum filled with water in my basement so I could hook up my old Textronixs Type RM35A oscilloscope. I first got readings from a fish ducer I new worked well and than hooked up mine and stared to turn pots until it looked the same. Not easy with no instructions but I did have a schematic. I brought lead and duct tape with me out on the boat for finial balancing. A real class act. The fish performed extremely well, steady as a rock.

[Tod]

Field-test




The ducer was held on by hose clamps so that I could experiment with the angle of the ducer to the fish. 10 degrees works well.

[Tod]

Field-test




This is a steam schooner in 50 feet of water and a relief of 5 feet. The ducer was at 45 degrees. I can see how important TGC (time gain control) is. If not enough gain you would not see the wreck (would be white), too much gain and all you see is black. I see how Sture did it, does any one else have a way I could do this in line with the gain control knob (it’s a 5K pot). I’m not good at designing circuits but with the right idea and components I can hack my way through the rest by t+e (trial and error).


Tod

[Carl]

Re: TGA's

>I can see how important TGC (time gain control) is. ...does any one else have a way I could do this in line with the gain control knob (it’s a 5K pot).


How are you doing the time gain control now? We (Analog Devices) have TGAs (time-gain amps) that are used in the medical ultrasound market that might work well for sonar. I believe that one is the AD600 - I will see what else we have.


- Carl

[Tod]

Re: TGA's

Carl,


That's great. I went right to http://www.analog.com/ and got the info on the AD600 stuff. I might just be able to put something together with it.


Thanks,


Tod

[Tod]

Re: Field-test

By the way all the elements came out of the second ducer I made. The solder joints broke off and I just made new ones(cheap basted). I didn’t expect results this good,Ok I didn't expect any, I was just trying to learn how to make this thing.


Tod