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Reply With QuoteThanks Bob and Rickie! Do you have a drawing of a transD with a drawing of how the waves come out of it? I remember something about the piezos being tilted at an angle inside the ducer?
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Sonar Quiz #12
Bob gave a good description...
Basically...sound has natural tendencies...
Given the same amount of "push" (from the transmitter in this case)...low frequencies will travel further ....
This is also part of the reason why the edges of the 800kHz HB SI image is darker out to the sides of the display ...the higher frequency just will not travel as far as the 455kHz...(the beam form is also part of this reason)...
Conversely, the 455kHz HB SI image is always fuzzier (than the 800kHz)...because the lower frequency sine wave is "missing" minute targets that the 800kHz frequency sine wave will "hit"...
Rickie
Last edited by rnvinc; 08-23-2017 at 10:34 AM.
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Thanks Bob and Rickie! Do you have a drawing of a transD with a drawing of how the waves come out of it? I remember something about the piezos being tilted at an angle inside the ducer?
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Sonar Quiz #12
I don't have a depiction of the actual sine waves that come out of the xducer...(I don't recall ever seeing a pic of the actual sine wave as it emits out from the piezoes)...
Here is the HB depictions of the 455kHz SI beams (lower left image)...and the 800kHz SI beams (right image)...
(These depictions also show the 2d "cone" beam right under the xducer)...
Rickie
Last edited by rnvinc; 08-23-2017 at 10:38 AM.
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Thanks!
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If you check out the frequencies in most military applications they are low for the improved ranges. Minesweeping sonars are usually higher frequencies for better detail and shorter range. Fathometers are normally very low frequencies. Oops...guess we're talking fishing here...LOL But amazing how the same basic principles still apply.
