Topic: Would changing sonar beam from 200 to 200/83kHz improve SI image?

[newkid4si]

I'm going to try and ask this the best that I can, but my thinking my be kind of convoluted.

The default "Beam Select" under the Sonar Menu Tab on an 1199 is 200kHz. The options are 200/83, 200, and 83kHz.

The SI beam consist of 455kHz and 200/83 from the Dual Beam PLUS portion of the transducer.

Do you think changing from the default (200) to 200/83 in the Sonar Menu Tab would improve the SI image?

I remember a post about turning off/leaving off the 83kHz to improve the SI image while recording. (smaller file size).

          Mike

[sonar2000]

Mike, are you asking about down imaging vs side imaging (sidescan). 200/83 is the frequency for the 2d look just below the boat. I think the DI really uses the SS frequency of 455. Although I am not really sure what HB is doing with DI.
This will be interesting to see what other experts have to say.
Chuck

[Bob B]

The first thing to know is that the unit is always running 200 khz even if only 83 khz is selected.  It always uses 200 Khz for the SI and for digital depth.

Humminbird seems to be struggling with the 200/83 dual beam setting.  With the core units a couple of years ago, Humminbird changed the transducer ping sequence (the SI was being pinged more frequently and the 2D less frequently) in an effort to get better DI and SI.  The result was that the 2D was VERY pixelated..... Everything worked better if the unit was running 200 Khz only. Any software release for the 1197 beyond 6.310 has very bad SI as well as pixelated 2D.

About a year ago, Humminbird came out with Jigging mode in the core series SI units, which brought the ping sequence back to what it was at the 6.49 software release level when Jigging mode was on.

Now ... with the 2.7 software release of the Onix, Humminbird has again messed up the dual beam capabilities of the unit.  In this case they modified the software to make the unit capable of doing chirp with the standard transducer .... but get REALLY bad imaging in some scenario when utilizing dual beam.

So......The bottom line is that using the dual beam 200/83 2D setting with the newer software releases causes problems......Using 200khz only seems to result in better SI and DI and 2D performance...but at the sacrifice of the dual beam features and the wider coverage of the 83 Khz.

[newkid4si]

Chuck and Bob

     Thank you for your answers.

  Chuck-- I am only thinking about SI now. In the owners manual where it shows how the SI beam is formed, the drawing shows 20° of 200kHz and 60° of 83kHz directly under the boat

  and 86° of 455kHz transmitted to each side.  I realize that 20° (200kHz only) + 86° + 86°  is greater than 180°, but I wondered if the 60° of 83kHz directly under the boat would improve the  quality of the image.

  Bob provided good info in that the 200/83 doesn't work that well.  I'm now going with the  "if it isn't broke, don't fix it"  plan.

         Mike

           

[Bob B]

I think the picture you are looking at shows the relative coverage of the various beams .... the 200 and 83 Khz aren't used for the SI image except to 200 Khz is determine the water column range.... only the 455 .... or 800, whichever is selected is used to generate the SI image.

Using the 83 Khz frequency is more likely to reduce the SI performance because the SI has to share resources with an additional frequency being pinged .... Hope that makes some sense.

[newkid4si]

Sure does Bob.  Kind of confusing when the picture was in the SI chapter.  Thanks for your help.

       Mike

[Whistler]

Newkid - If you enable the 83/200 mode you will get the "zipper" effect on the SI image.  It really screw it up.  Like the others mentioned, HB introduced this "feature" </sarcasm> a few revs back.  Prior to that, SI operatee fine in 83/200 but not now.

[mike fish]

Kind of off topic but does the 83/200 work correctly on a stand alone finder like a 859, 959, etc. ?

[Bob B]

Kind of off topic but does the 83/200 work correctly on a stand alone finder like a 859, 959, etc. ?

Yes, it is fine with the 2D models and the DI models as far as I know.

The jigging mode fix in the later releases for the 98 and 99 series units made it better, but still doesn't seem as good as 6.49 ..... The 1197 is still pretty messed up with any release beyond 6.310.

[fishreed]

Why don't you just use the SI/DB splitter cable and use the SI transducer for side imaging   AND a separate DB 200/83kz transducer for 2D. Better yet use 2 SI hdsi transducers with one dedicated to the port and another dedicated to starboard And a separate DB 83/200KZ transducer.  It think that will solve your problem pretty darn nice as it sure did for me.