kokanee fish finder/depth/gps unit

[strikezone]

My Lowrance HDS7 unit broke. I'm looking for any suggestions about what unit is out there that shows kokanee the best. I'd like one with the largest cone area possible. I'm open to all suggestions. Thank you for any help.

Denny

[Larry3215]

The first question is whats your budget?

All the newer units work pretty well these days, but I would highly recommend you try to get a CHIRP capable unit and CHIRP transducer. CHIRP is a big improvement as far as target separation and noise reduction.

As far as cone angles, for any given transducer, lower frequencies have wider cone angles and higher frequencies have narrower cone angles. The flip side to that is lower frequencies show less target separation and less detail than higher frequencies, so its a trade-off.

Thats one reason CHIRP shines - it gives you the best of both worlds by sweeping through a range of frequencies rather than sticking on one.

[G-Man]

As far as cone angles, for any given transducer, lower frequencies have wider cone angles and higher frequencies have narrower cone angles. The flip side to that is lower frequencies show less target separation and less detail than higher frequencies, so its a trade-off.

This is not a 100% true statement. Cone angle is all about how the transducer's element is shaped. The specs on the transducer you will be using will determine what cone angle(s) you are going to get from a given frequency. The reason why the lower frequencies tend to have the wider cone angles is because they penetrate the water better than higher frequencies. This enables one to spread out the beam and still be able to reach deep targets, but at a sacrifice to image detail. Unless you intend to do some deep sea fishing, there is no need to get a low frequency (50Khz) sonar/transducer setup. You can find mid-range frequency (83Khz) setups with very wide cone angles which will give you more than enough depth coverage.

[Larry3215]

Im not sure what I got wrong, since you said essentially the same thing I did. There is only one transducer on the market that I can think of off the top of my head, that doesnt have a wider cone angle at lower frequencies that it does at higher frequencies and you not likely to find it on a kokanee boat. Thats a $1400 B175H-W thru-hull which has a constant beam width across it entire frequency range. Every other multi-frequency transducer I know of follows the general rule.

So where exactly did I go wrong?

[G-Man]

You can find 200Khz skimmer transducers that spread out a beam to 30 or even 40 degrees, and they don't run in the $1000s. Granted these tranducers are single frequency units, however my point was, if you truly want to set up a system that utilizes a higher frequency and wide cone angle, it can be done. Transducers are the easiest way to both limit and increase your sonar unit's performance. A transducer that does it all is a compromise, there is a reason that $1000 tranducers exist. If you purchase a high end sonar unit and want to unlock its potential, you'll need to match it up with a high end transducer designed for your specific application.

[cobrar543]

And what trolling motor do you have ? If I was to replace my Lorance I would get a hummingbird due to the fact it pairs with my Minn kota and sets my autopilot to follow a contour or temp range.

[Bodofish]

G-Man hit the cone shape and size on the head. While frequency plays a role with the distance (Obviously as it penetrates farther the cone will get wider the farther it goes.) the real factor is the shape of transducer. At a given distance from the transducer the cone or ping area will be the same regardless of the frequency. Convex will provide a wider ping area and concave will provide a more narrow ping area or cone in laymen's parlance. Personally I don't see any reason to use anything but the 200 and plus Khz as it's good to 600 feet deep. I'm not aware of many fishes we might want to catch that go deeper than that.

[Larry3215]

LOL to both of you! To argue or not to argue.... I havent had enough coffee.....

[buzzbob]

Here is a screen shot from Odell Lake 2016 July where thousands of Kokanee stack up near Trapper Creek. The sonar is a Furuno 1670f with accufish which shows individual fish with the actual length of each fish. When accufish is turned on, the 50/200 frequencies blend togther. The fish length shows when the fish is inside both frequencies at he same time so echos without lengths are in the 50 frequency only and not directly under the boat. The screen shot shows one 30" lake trout suspended just below the Kokanee so knowing the fish size is imperative when targeting multiple species at the same.

[Bodofish]

LOL to both of you! To argue or not to argue.... I havent had enough coffee.....

There is no arguing, it is what it is. Frequency does not change the size of the cone, that can only be done by the shape of the transducer. The illustration below shows why the manufactures say the lower frequency transducer makes a wider "cone". The tip of the triangle is the transducer, the blue part is only serviced by the higher frequency, say the line in the middle is the 600' mark. The red part and the blue part are serviced by the lower frequency. The lower frequency can travel farther therefor making a larger/wider cone when they surpass the reach of the higher frequency. Sound waves and light waves are a lot alike, they travel in a straight line unless acted on by an outside force.

[Larry3215]

LOL to both of you! To argue or not to argue.... I havent had enough coffee.....

There is no arguing, it is what it is. Frequency does not change the size of the cone, that can only be done by the shape of the transducer. The illustration below shows why the manufactures say the lower frequency transducer makes a wider "cone". The tip of the triangle is the transducer, the blue part is only serviced by the higher frequency, say the line in the middle is the 600' mark. The red part and the blue part are serviced by the lower frequency. The lower frequency can travel farther therefor making a larger/wider cone when they surpass the reach of the higher frequency. Sound waves and light waves are a lot alike, they travel in a straight line unless acted on by an outside force.

Sorry, thats not what I said - please re-read my posts - and thats definitely not whats going on with transducers and cone angles and frequencies. Not even close.

First - the "angle" of the cone is different. Wider cone angles cover more or less bottom - at the same exact depth - because the angle of the cone or the beam, is wider or narrower. Depth/penetration is a separate issue altogether and not related to cone angles except incidentally.

Second - I said that for any given multi frequency transducer - like ALL CHIRP transducers ALL 2D/down/sideview combo transducers sold these days - that the cone angle was wider for the lower frequencies and narrower for the higher frequencies - on that particular transducer. I only know of one exception to that "general rule" and that one has the same cone angle its entire frequency range. Every other multi frequency transducer made by every manufacturer I know of, follows that "rule". Its not really a rule of course, its just the way the physics works out.

That "rule" has nothing to do with depths or concave or convex anything and doesnt require you to know or understand anything about how the crystals are shaped. Its just the way (almost) all multi frequency transducers function. There are NO single multi frequency transducers made by anyone that that have wider cone angles at higher frequencies and narrower cone angles at lower frequencies. None. Period.

Yes, you can find different 200 khz 2D transducers with different cone angles and different mfg's transducers have different cone angles. That not what I was talking about.

Finally, when we talk about specific "cone angles" we are not really being very accurate at all. Things are far more complex than a simple cone or single angle. Take a look at some of these images and you will get an idea. Or Google "sonar cone angle" or "sonar coverage" or anything like that.

choosing-transducer-angle_250x321.gif (10.46 KiB) Viewed 13263 times

[Larry3215]

Or these

sonarelement324.jpg (14.7 KiB) Viewed 13263 times

[Bodofish]

Having built a handful of specialty sonars for the Navy, active and passive, I will submit that what you are seeing are multiple transmitters or pingers in a single transducer body, as I've said before, the shape or size of the "cone" has nothing to do with the frequency, it's the shape of the transmitter or pinger. I will agree that the companies produce a low frequency transducer that has a wider cone but the width of the cone still doesn't have anything to do with the frequency, it's still the shape of the transmitter.

In building the sonars for the Navy we tested and dissected many off the shelf units and they all worked as the picture I posted. Granted that was a number of years ago and I'm sure technology has changed however, basic sonar theory has not.

[G-Man]

Before this gets out of control, let me just say this. My response was in regards to the implication that you should buy a lower frequency unit if you want a wide cone angle. I felt that, given this advice, strikezone my have ended up purchasing a unit with a 50kHz signal just because he thought it would supply the widest cone angle. Cone angle has nothing to do with the head unit and everything to do with the transducer, so I thought it best to make that clarification. Much like purchasing speakers for your sound system, a transducer tailors your system to what you want it to do. With the use of the higher frequencies and high definition displays, today's recreational sonar units can display much more detail than what was available in days past.

My suggestion would be to look at a unit that uses 200Khz, single or dual channel, has chirp capability and a high definition screen, this will be the primary frequency you will use. It will supply a great amount of detail and is good down to 600' or more depending on the head unit you get. As for the transducer, if one comes with the unit fine, but you'll want to look at the specs to see if it is going to meet your needs. Some sonar manufacturers have a wide variety of transducers from which to choose, others not so much. As I mentioned before, you can purchase an aftermarket transducer that will push that 200kHz signal out in a wide cone, so you might want to work backwards. Select a transducer and match it to a head unit. You can even mount multiple transducers on your boat and just switch between them when needed.

[Larry3215]

I think our bickering chased Denny off.

Bodo - I dont know enough about Navy sonar to argue about it other than its pretty much nothing like our sonar. I have read all the Tom Clancy submarine novels though

G-Man - I can pretty much agree with your last post except that I wasnt trying to suggest he buy a 50 khz transducer. Just pointing out the 'general rule' that frequency/cone angles follow. I agree 100% - as I said in my first post - that CHIRP will serve him better than any other option. By sweeping through a range of frequencies, CHIRP gives you the best of both worlds as far as penetration, beam width, target separation and noise reduction.

I would also add that sideview can be very helpful when koke fishing if they are schooling. Side and downview are not all that useful for seeing individual fish but they work great when they are schooling.

Still, budget is the first thing he needs to establish before we can make any specific recommendations. At the low end of things he wont have many choices at all and the options and features get better as $$ goes up.

My #1 recommendation for finding fish that are not directly under the transducer, is to use a Garmin Panoptix transducer. I have seen individual fish and schools of bait fish, kokanee and perch at more than 200 feet away - in any direction around the boat - in real time. I have watched schools of fish and individual fish move out of the way of the boat before we got to them. There is nothing else available from anyone that even comes close. It puts all other sonar to shame as far as finding fish.

But - your looking at close to $2K to get started.

[Bodofish]

Yeah, probably did but he's made 5 posts up to this point and I'm betting he'll be back.
I agree 100% except that a sonar is sonar is a sonar it doesn't know if its on a navy boat or your boat, they're all still bound by the laws of physics. There is no arguing you have a great toy in your FF. And yes, a side scan is way more useful for kokes or trout as both are very skittish and when a boat goes over and makes a shadow, they're gone. I've thought long and hard about a side scan but just haven't wanted to put the $$$$$$ into it. so it's long lines and planers.

[hewesfisher]

Yeah, probably did but he's made 5 posts up to this point and I'm betting he'll be back.
I agree 100% except that a sonar is sonar is a sonar it doesn't know if its on a navy boat or your boat, they're all still bound by the laws of physics. There is no arguing you have a great toy in your FF. And yes, a side scan is way more useful for kokes or trout as both are very skittish and when a boat goes over and makes a shadow, they're gone. I've thought long and hard about a side scan but just haven't wanted to put the $$$$$$ into it. so it's long lines and planers.

And they work very well indeed. Cannot tell you how many times I'm asked if I mark any trout when they are in the top 12' - 15' of the water column. Answer is always the same, no, but who cares if you're catching 'em.

[Bodofish]

Yeah, probably did but he's made 5 posts up to this point and I'm betting he'll be back.
I agree 100% except that a sonar is sonar is a sonar it doesn't know if its on a navy boat or your boat, they're all still bound by the laws of physics. There is no arguing you have a great toy in your FF. And yes, a side scan is way more useful for kokes or trout as both are very skittish and when a boat goes over and makes a shadow, they're gone. I've thought long and hard about a side scan but just haven't wanted to put the $$$$$$ into it. so it's long lines and planers.

And they work very well indeed. Cannot tell you how many times I'm asked if I mark any trout when they are in the top 12' - 15' of the water column. Answer is always the same, no, but who cares if you're catching 'em.

Oldest trolling quote around, "You never catch the ones you see."

[TrackerPro16]

This thread caught my eye as I am considering upgrading my electronics this year. Put together my 'dream' package and it is around $5K!!! Not sure if it would be worth it. If the bite is off knowing exactly where they are would be even more frustrating! And expensive!

[Amx]

Not like that 5K is good for only one day. Then have to spend another 5k for the next day of fishing.

Finding the school with the depthfinder lets you sit in one spot, or follow the school, and try other lures quickly. Instead of trying one lure for an hour around the lake, then another lure around the lake and so on.