Thread: Humminbird 899 Side Image Transducer.

There is a kind of misnomer about the stock XNT 9 SI 180 T in the forum conversations and it not being able to take advantage of the 800kHz frequency like the XHS 9 HDSI 180 T upgrade xducer ...

Both xducers have the same amount of SI piezoes (1 left and 1 right) ...

The difference is ...the piezoes in the XHS 9 HDSI 180 T are manufactured by design to efficiently vibrate at 455kHz and 800kHz ...

The piezoes in the XNT 9 SI 180 T are only designed to efficiently vibrate at 455kHz ...

The 899ci SI has 2 separate SI frequency functionality possibilities that tell the SI transmitters what frequency(s) to send to the SI piezoes ...:

*The "HiDef Sidescan" Transducer Select menu setting tells the SI transmitters to fire at 455kHz or 800kHz (dependent on the "Image Frequency" setting under the sonar tab) ...

*The "Sidescan" Transducer Select menu setting tells the SI transmitters to fire at 455kHz (the only "Image Frequency" menu setting when the Transducer Select menu is set to "Sidescan") ...

If the stock XNT 9 SI 180 T is connected to the 899 ... And the "Transducer Select" menu is set to "HiDef Sidescan" = the SI transmitters can fire at 455kHz and 800kHz ...but the SI piezoes in the XNT 9 SI 180 T will not vibrate efficiently when the "Image Frequency" is set to 800kHz ...

The SI transmitters will send the 800kHz signal ... And the SI piezoes will vibrate with the 800kHz frequency signal ... Just not efficiently ....

Clear as mud ...??

Rickie

I think I got ya! So.... ur saying that my stock transducer is capable of sending a 800khz signal, just not capable of recieving it back to develope a nice image? So I will be needing to upgrade my transducer. I wish I would have known about the trade in option when I bought my graphs. They were just so new to me when I got it, the only thing I knew about them was that they came in a box. hahahahah

Most all piezoes are manufactured to vibrate efficiently at either a "single resonate frequency" or "dual resonate frequency" ...

Piezoes will vibrate at most any frequency signal that the transmitter sends to it ... Just not as efficiently as the designed frequency(s) ...more efficient vibration = stronger sound pulse = more reflection from echo targets = more received echo data to process ...

Your 899 can operate at a "single resonate frequency transmit" = "Sidescan" Transducer Select menu choice ...
Your 899 can operate at a "dual resonate frequency transmit" = "Hi Def Sidescan" Transducer Select menu choice ...

Your stock XNT 9 SI 180 T can vibrate at both the 455kHz and the 800kHz transmit = "Hi Def Sidescan" Transducer Select menu choice ...

With the stock XNT 9 SI 180 T attached, the 800kHz frequency transmit will not vibrate the SI piezoes effectively enough to create a strong enough sound pulse to make good SI images ...

Will the stock XNT 9 SI 180 T work on 800kHz ...?? ...Yup ...

But not as good as the XHS 9 HDSI 180 T ...

Rickie

Originally Posted by rnvinc

Most all piezoes are manufactured to vibrate efficiently at either a "single resonate frequency" or "dual resonate frequency" ...

Piezoes will vibrate at most any frequency signal that the transmitter sends to it ... Just not as efficiently as the designed frequency(s) ...more efficient vibration = stronger sound pulse = more reflection from echo targets = more received echo data to process ...

Your 899 can operate at a "single resonate frequency transmit" = "Sidescan" Transducer Select menu choice ...
Your 899 can operate at a "dual resonate frequency transmit" = "Hi Def Sidescan" Transducer Select menu choice ...

Your stock XNT 9 SI 180 T can vibrate at both the 455kHz and the 800kHz transmit = "Hi Def Sidescan" Transducer Select menu choice ...

With the stock XNT 9 SI 180 T attached, the 800kHz frequency transmit will not vibrate the SI piezoes effectively enough to create a strong enough sound pulse to make good SI images ...

Will the stock XNT 9 SI 180 T work on 800kHz ...?? ...Yup ...

But not as good as the XHS 9 HDSI 180 T ...

Rickie

This explanation helps me understand why a true CHIRP transducer might cost several thousand $$$. There will be transducers that will send out multiple frequencies(so they can claim CHIRP), but they will sacrifice quality for quantity.

I see!!! Thanks man! You have helped me come along way since i started this stuff.

Originally Posted by LowePro

I see!!! Thanks man! You have helped me come along way since i started this stuff.

There's nary a question I didn't ask myself when I started ...

Rickie

Some of the new SI units shipped with an 800 KHz "bug" and mine needed the repair work done.
If yourun 800 KHz it should "settle up" after the 1st full screen marches off...
If it's blown out & only a setting of 1 or 2 seem to work, you might give HB a call with your serial number ready.

I wasn't aware of the upgrade until long after the fact. Will I really see much resolution difference if I decide to purchase the new HD
transducer?