what about chirp

given the fact crappie like to hold tight to cover , does chirp help? i know it can help with say bass , walleye ,and cats holding close to the bottom. but what about in brush ? and if you have changed from a none chirp to a chirp unit can you tell the difference? if so would you buy your next unit without it or would that be a deal breaker ? sorry if y'all have heard this question before i am currently using a 365i ( grayline ) i going to buy a 7 or 9 in. si unit . i know anything , will blow what i am use to out of the water . but with the prices i have seen ,it will be a while be i can do again. thanks

IF U WANT TO SEE FISH IN BRUSH THEN GET A GOOD DI UNIT,CASE SOLVE,WISH THEY ALL WERE THAT EASY:Rofl

so for example, and i am i just using this one because its on my list as is some Lowrance's and Garmin . but say a helix 9 di is better than a helix 9si which also has di is better for di

A helix 9,2d unit,coupled with an 360 would be a great option imo.

In general, a chirp unit will have better 2D than a non-chirp unit ....... and a unit with a dedicated DI transducer will have better DI than one that doesn't.
The DI will have the best target separation since the operating frequency is higher and also the beam width is much more narrow front to back. The drawback to DI is that the beam is much wider side to side and it is more difficult to determine exactly where an object or fish is located.

There are some who are extremely knowledgeable crappie fishermen who argue that 2D isn't necessary.....You only need DI ...... I personally wouldn't have a unit that doesn't have 2d because boat positioning and accurate waypoint marking are much easier.....Of course the 360 takes all that to a higher level.

2D, DI, SI, and 360 together ..... with each used for their strength would be the ultimate in my mind......and as Kosmo has stated, you could get all that fairly economically with a Helix 9 2D GPS unit and a 360.

Garmin is developing new technologies with the Panoptix technology, and I have talked to some who have the Panoptix down view .... sounds like another terrific tool.

thanks for the info guys it is very informative and help full.

You were asking about chirp,but I guess u didn't really get any comments on chirp.I don't have a chirp unit,so really don't no for sure,but I don't think chirp will do a whole lot in shallow water

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Originally Posted by kosmo

You were asking about chirp,but I guess u didn't really get any comments on chirp.I don't have a chirp unit,so really don't no for sure,but I don't think chirp will do a whole lot in shallow water

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I spent some time a while back watching videos of various chirp units.....and Kosmo is correct that the benefits of chirp dissipate very quickly the more shallow the water is.

Another interesting thing about chirp units is that it appears that the improved 2D image may not be from the chirp frequencies themselves as much as it is from the enhanced 2D processing capabilities of the unit and the chirp transducers are generally higher quality transducers.
On one of the videos I watched, the user was running the unit at a fixed frequency around 100Khz and was getting VERY good 2D images .... he temporarily switched over to running chirp in that range and the 2D image actually got worse ..... he switched back to a fixed frequency and the image improved again.
That is some real food for thought when it comes to a chirp unit.

I would be interested if anyone who has a chirp unit has done any comparisons to a fixed frequency on their unit compared to a "chirped frequency." Videos of this comparison would be great.

No sonar expert here but my career was in missiles and radar for 38 years....very familiar with CHIRP. It was first designed for use in radars for the same reason you want it for crappie....target separation.....in radars CHIRP is also used for other functions as well. Theoretically the lower price units you see that are advertised as CHIRP are CHIRP...but the frequency spread is nowhere near as wide as say a five thousand dollar unit....and the high end unit can give you great separation at 10,000 feet of depth. Obviously you are not worried about that...LOL. But the bigger the frequency span the better the target separation. CHIRP can also be used in your di and si....which would really blow us away with what we would see. As with all things today it is about cost. The Digital Signal Processors are much cheaper than years ago...and will continue to drop in price which will be good for us. But right now a high end CHIRP unit is not in most folks price range. The transducer has a big part in it also....better transducer more cost. As Bob said I also would want to see a CHIRP unit in operation....I have seen the Dragon Fly 7 and I saw nothing there that would make me want to buy one....and give up my now obsolete HB 899.

Regards

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Originally Posted by Alphahawk

No sonar expert here but my career was in missiles and radar for 38 years....very familiar with CHIRP. It was first designed for use in radars for the same reason you want it for crappie....target separation.....in radars CHIRP is also used for other functions as well. Theoretically the lower price units you see that are advertised as CHIRP are CHIRP...but the frequency spread is nowhere near as wide as say a five thousand dollar unit....and the high end unit can give you great separation at 10,000 feet of depth. Obviously you are not worried about that...LOL. But the bigger the frequency span the better the target separation. CHIRP can also be used in your di and si....which would really blow us away with what we would see. As with all things today it is about cost. The Digital Signal Processors are much cheaper than years ago...and will continue to drop in price which will be good for us. But right now a high end CHIRP unit is not in most folks price range. The transducer has a big part in it also....better transducer more cost. As Bob said I also would want to see a CHIRP unit in operation....I have seen the Dragon Fly 7 and I saw nothing there that would make me want to buy one....and give up my now obsolete HB 899.

Regards

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When the first came out with Side Imaging it made me think of SLAR.

i live in southern middle Tennessee, and fish 12 months of the year, 70% of the time i fish deep 14 to 26 ft or deeper. the exception would be the spring time . i guess the main thing i am looking for besides mapping and a good gps is structure id.( brush,standing timber )ect. and how the fish are responding to it. like the way crappie will stack up , are they active (above) the brush or not so (down) in the brush ect. better target separation, was what i had in mind but also side view to get a wider view while running river channel and contour lines and down imaging for a better look. 360 would be nice ,but that would all most double what i am looking to spend. but from what i learning from you guys is its not that simple. but still better than what i am use too. thanks for all the info. please keep coming i want to learn all i can.

This is regular Sonar ... Blobs like we are used to ...

http://i477.photobucket.com/albums/r...psff8vpjjm.png

This is CHIRP ...(at fixed frequency in this example) ...

http://i477.photobucket.com/albums/r...pspqqwzteq.png

Prettier arches no doubt ...

One huge benefit is being able to select any frequency within the bandwidth ...and not be stuck with 200kHz or 83kHz ...

Rickie

Rickie .... what are your thoughts about why a chirp unit is better at a fixed frequency?
Good point on the ability to be able to choose what frequency you want to run.

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Originally Posted by BobB

Rickie .... what are your thoughts about why a chirp unit is better at a fixed frequency?
Good point on the ability to be able to choose what frequency you want to run.

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I would offer to alter that slightly and say "why is a CHIRP unit better at a fixed frequency in shallower water" ...

The biggest benefit I have read is the ability to alter the cone angle to match the Enviromental conditions for that specific point in time (changing the frequency effectively changes the cone angle) ...

Shallow water doesn't really need the CHIRP sweep frequency characteristic of being able to transmit more power into the water (than toneburst pulse Sonar) with less associated noise ...

So the higher quality processing of the CHIRP sounder ... and the ability to micro-adjust the cone angle to meet the specific conditions seem to be the benefits in shallow water ...

Rickie

At least some of these fish,suspended above the tree stump are crappie.I see them on the 200khz.Chirp,used here,on a fixed frequency would show better target separation. I doubt it would help enough to make any difference tho.?http://i826.photobucket.com/albums/z...psp3egvcfd.jpg

kosmo looking at your first picture it is easy to interpret i can all most see the down image in my mind, Rickie your picture without chirp , is harder if on my home lake ( Tims Ford ) with out down scan i would guess i was looking at bait , not beaning flatten out maybe some bass following not in full feeding mode . but in the second picture with chirp it looks more like a school of white bass . another good name for this post would be , what you need to know before you buy a good unit.