- #1
Adder_Noir
- 239
- 0
Hi!
I've just bought a fish finder and while playing around with it, it turns out that it isn't much good in shallow water. Now I'd guess it's using ultrasound as it can operate at depths up to several hundred feet and I presume therefore is getting far too much ground penetration at shallow depths and therefore (again I assume) a poor reading returned to the receiver.
So my question is what sound frequencies would be reliable to locate fish and underwater objects at very shallow depths such as those in canals? I assume ultrasound is going too far for this? Surely I don't need to transmit in frequencies of 40kHz to pick-up fish that are in water only 3-6 feet deep?
Does anyone know what kind of frequencies I should be using for this? And could I pick-them up with a sensitive microphone run through an op-amp?
Thanks in advance for any help offered
I've just bought a fish finder and while playing around with it, it turns out that it isn't much good in shallow water. Now I'd guess it's using ultrasound as it can operate at depths up to several hundred feet and I presume therefore is getting far too much ground penetration at shallow depths and therefore (again I assume) a poor reading returned to the receiver.
So my question is what sound frequencies would be reliable to locate fish and underwater objects at very shallow depths such as those in canals? I assume ultrasound is going too far for this? Surely I don't need to transmit in frequencies of 40kHz to pick-up fish that are in water only 3-6 feet deep?
Does anyone know what kind of frequencies I should be using for this? And could I pick-them up with a sensitive microphone run through an op-amp?
Thanks in advance for any help offered