What exactly is target separation?

[JacobMHD]

Is it simply a flashers ability to recognize two objects versus only one at the given distance they are apart from one another? How important do you feel it is in a flashers performance? Why is there such a variance between Humminbird's product line and Vexilar's?

[Cicada]

From my understanding, that would be true, but only on a verticle plane. It can't tell you that there are two fish two inches apart, but at the same level. It can tell you that you have two targets when one is above the other or one target above the bottom. It can be very important at times. There are times, however, when this isn't that important. If you are fishing where all the fish are the same general size and/or species, not a big deal. If you are in an area where several species of varying sizes roam, it can help you figure out what you are most likely looking at. Maybe I downplay the importance might be because I have on old vex. The target separation isn't the best available, but I know how to use it and it gives me all that I want.

[Deitz Dittrich]

Target separation is just what is says.. how much distance is needed for the unit to understand that there are 2 separate objects. On older units if things were within 4" of each other, it would show up as one object. Now with some of the more powerful units that is down to just above an inch.

HOw that relates to your fishing, on hard days, you can often miss the feel of the bite, you can now make a more accurate guess on if the fish has it or not and just set the hook without feeling anything. It also gives you much better bottom read. As there will be a smaller dead zone, unless you are on a drop off or have large rocks or weeds beneath you.

Hope this helps.

[Surface Tension]

That is correct the distance two targets become one on a vertical line.

You can get an indication of two targets on a horizontal plane as well. The most simplistic is by lifting your lure. Another is reading the different colors. Lets say your lure is marked at the weakest color which it should be. A fish coming in at the same depth as your lure will enter the cone angle and of coarse will be marked as a weak signal. On your flasher that might be enough to either give you a thicker line but still marked as weak color or it could change that weak color to the next hottest color. As the target comes closer to your lure it is getting toward the center of the cone angle it will eventually read as your hottest color. Now you know why it is so important to set and fine tune your gain. Your lure should be displayed as your weakest color. If it is shown as hot then you missing out on a lot of information.

[JacobMHD]

Do you feel that the target separation indicated by Humminbird (2 1/2") as compared to Vexilar (1/2") is something to be of concern?

[BoxMN]

I can't say about the comparison between the two, but I can say that with my unit (brand x...) I often catch fish just by setting the hook using the method Deitz mentions above. I caught almost all of my (little) crappies on Bald Eagle the other day doing just that. I won't even bother fishing anymore if I don't have my locator with, unless tipup fishing or bigger jigs for pike.

[fishwater]

Do you feel that the target separation indicated by Humminbird (2 1/2") as compared to Vexilar (1/2") is something to be of concern?

Jacob, Vexilar is confusing you with terms. They claim to have a 1/2" target ID. This is different than having a 1/2" target separation. I believe their target seperation is around 2.5" - at least that is what the specs on the FL18 say.

[Walleye Guy]

Keep in mind that on the screen of any of the flasher units, one foot in the water column is represented by a space of 3/8 to 1/2 inch on the dial of the flasher. This varies some based on what depth range you are using and if you are in zoom mode or not.

This means that a 1/2 inch target represents 1/24 of that 3/8 to 1/2 inch space on the flasher dial. That is a pretty tiny area. Target separation is important but recognize that it may be difficult to distinguish on the screen because of these ratios.

If you want to test this theory, take two tiny split shots (BB size) and place them next to each other on your line. Take a reading on your flasher. Move the split shots to .25 inch, then .5 inch, the .75 inch etc. Take a reading with the flasher each time you change the spacing. Do the same at deeper depths and depth ranges and with the zoom on and off. Repeat with larger split shots and greater distances between them.

While it takes a little while to do, it is a pretty interesting exercise and it gives you a pretty good understanding of what your flasher can pick up and what it cannot.

[JacobMHD]

Interesting. I couldn't figure out how two flashers with very similar technology could have such a discrepency in technology. Sounds like the marketing team at vexilar did their job. Thanks for the insight.

[tsande00]

If you want to test this theory, take two tiny split shots (BB size) and place them next to each other on your line. Take a reading on your flasher. Move the split shots to .25 inch, then .5 inch, the .75 inch etc. Take a reading with the flasher each time you change the spacing. Do the same at deeper depths and depth ranges and with the zoom on and off. Repeat with larger split shots and greater distances between them.

While it takes a little while to do, it is a pretty interesting exercise and it gives you a pretty good understanding of what your flasher can pick up and what it cannot.

I can't wait to try this the next time out on the ice.

[DTro]

I like the greater target seperation to see if I lost my bait or not.

[Ed Carlson]

Originally Posted By: JacobMHD

Do you feel that the target separation indicated by Humminbird (2 1/2") as compared to Vexilar (1/2") is something to be of concern?

Jacob, Vexilar is confusing you with terms. They claim to have a 1/2" target ID. This is different than having a 1/2" target separation. I believe their target seperation is around 2.5" - at least that is what the specs on the FL18 say.

The Target separation is 1/2 on the FL-20 in AZ Mode.

Sonar resolution, or target separation, is the units ability to separate one target from another. For example, separating a fish from the bottom or one fish from another one close by. This is a function of the transmitters pulse width, or how long the transmit burst lasts. The shorter the burst the closer the sonar can separate two targets. The FL-12 series can separate targets within 3 inches or so on the 20' depth range. The deeper the range the longer the transmit burst, and thus, the separation increases.

Display resolution defines how small of a line the units display can draw. This specification is the one that probably affects the user the most. The better the display resolution the more detail the display will have. For example, the FL-20 can draw 525 individual lines around the display. When the range is selected to the 20 foot scale each line represents less than 1/2 inch. As the range increases the display resolution decreases.

A factor in target separation that often gets overlooked in the Hummingbird is the line segment width, even though they list it as 1 more line segment than the Vexilar, the individual segments are larger in width than the Vexilar is...this effects the separation and target ID. For the size of the displays on the Humminbirds if they tripled the segment count, it would have been much tighter, and far tighter in target ID.

Proper gain calibration in any flasher is critical to get the best seperation and target ID, so more often than not, that is the #1 determining factor in optimum target separation.

Be is 2.5" or 1/2", in any given situation proper user gain calibration will make the most significant impact on true seperation and Target ID.

[fishwater]

For example, the FL-20 can draw 525 individual lines around the display. When the range is selected to the 20 foot scale each line represents less than 1/2 inch.

Ed, can a FL20 actually display anything as a single band and still have enough gain to actually fish with the unit?? I've never seen that. Display resolution is also different beast than target separation.

[Ed Carlson]

If by a single band you mean a single line segment, then yes it can.

Single segment target returns are common even when locked onto a tiny lure at a low gain setting, even with larger more prominent and dominant sonar targets around. Again the gain setting will have a great impact on fine tuning this ability.

I often can see single segments that are sonar return targets such as tiny air bubbles rise from the bottom or at times pesky bugs. I can see my snap, than the lure, and the bait on a jig in separate segments, if well tuned.

Just as important is the ability to tune out them unwanted single return segments when one wished to do so. They are often perceived as just clutter to many, and still see the best return on your presentation as you can achieve. This is why in shallow waters I more often will be operating in the LP Mode.

[herefish101]

I love being able to read my jig and my bait at the same time, the unit i own just might have the best target seperation of them all(in my own opinion). i'v read my bait my hook and my weight, all at the same time.