Deeper question

[elmoputney]

Looks like a chirp plus to me I think, basically that one is the slightly older model, still improvements on the pro +, but depending on what's changed with the chirp +2, then it probably isn't as good as the latest one (don't know what the differences are though) 

[...]

https://deepersonar.com/uk/en_gb/products/smart-sonar-chirp-plus

 

[Carpbell_ll]

3 hours ago, newmarket said:

Thanks CB , appreciate that but w hat is meant by better detail exactly ?

Anybody else in the know ?

you get to see where the weed would be only a light cover or jungle shows up little clear spots you might not find with an older model  can tell you how thick silt is or if it's a thin coat over a hard bit. that sort of thing once you get the hang of it.

[newmarket]

2 hours ago, Highy said:

https://deepersonar.com/uk/en_gb/products/smart-sonar-chirp-plus

 

Thanks everyone I think I’ll all stop pestering you all now . 
I think what was confusing me was the fact that although there are a few different models , the newer ones obviously with a few more advanced features , every advert you come across appears to have a different box , I’ve seen at least 6 different ones .

Maybe it’s just me being a dope 🙄 they’re probably just that . Adverts . 
 

I think they look really useful little tools , especially on an empty lake .

But as I say , there’s a long long list of more essential items I need to acquire before stuff like that appears .

Good God have you seen the price of a basic chair ???? 😂

[carpepecheur]

19 hours ago, newmarket said:

There’s obviously something I’m not getting here . 
Having googled these things a million times and scoured this forum and others for info , everybody except obviously the super rich ones seem to utilise the deeper chirp+ .

No mention anywhere of this Deeper Chirp+ that everybody seems to use ?

Confused.com

Dear confused.com

I understand your confusion. I have been using a Deeper Pro + since they were first available roughly 10 years ago. They are an incredible bit of kit but I feel their capabilities are masked in traditional carp marketing speak. I have no experience of other models but this is what I understand.

There seems to be no such thing as a Deeper Chirp +

If the model is followed by a + sign it signifies that it is capable of using 2 different frequencies.

If the model is followed by a +2 sign it means it uses three different frequencies,

If it has a CHIRP designation it means it uses a special technology. According to Deeper, “CHIRP sends a continuous sweep of frequencies ranging from low to high, interpreting these frequencies individually upon their return.” For the life of me, I cannot understand what this means or how it is useful. The manual seems to suggest that you choose which frequency to use. There also seems to be a feature where the frequency changes according to depth of water.

If you do not understand the relevance of frequency here is some very basic information.

An echo sounder (NEVER call them fish finders, this is totally misleading marketing speak) uses a transducer (basically a combined loud speaker and microphone combined) to generate a noise and record when an echo from that noise is received.

There is a pulse rate which is the number of times a sound is generated per second. If you put your ear to the transducer you will hear a rapid clicking noise. This is 15 time per second for all the Deepers apart from the very basic (non GPS) model which uses 10 clicks per second.

The frequency of the sound determines what gets picked up. Think of a guitar. The top string E sounds a lot different from the bottom string E. The top string is a high frequency – the bottom string is a low frequency. Here is the first indication of why frequency is important. If you hear a band playing loud music from a long way off or when a car passes playing loud music, you often hear only the boom boom boom of the base and not the rest of the music.

This is because the lower the frequency – the greater the ability to penetrate the intervening space. So in an echo sounder a low frequency could be used to penetrate weed and locate the actual bottom.

Conversely, a high frequency is quickly absorbed so it might only show you the top of the weed.  If you have a thermocline for example it could show up on a high frequency as a false bottom (but this is very rare) 

The other feature of frequency is the area is covered by the pulse. High frequencies can be focused more accurately than low frequencies. In marketing speak this is described as a narrow cone or a wide cone from which reflections are picked up.

For example in the Pro +2

675 kHz gives 7⁰ cone

240 kHz gives 20^o cone

100 kHz gives 47⁰ cone

I hope, Newmarket this helps you understand what the models mean. If I were on a budget, I would choose the PRO + . Even 10 years later and with GPS no longer working on it I still use it for feature identification and mapping (by attaching my phone and Deeper to a bait boat).

BTW give my love to beautiful Grays – I used to go to school there in the early 1960’s

[...]

Very good watch and gives a good understanding of how I also use my Deeper Chirp +

[newmarket]

1 hour ago, carpepecheur said:

Dear confused.com

I understand your confusion. I have been using a Deeper Pro + since they were first available roughly 10 years ago. They are an incredible bit of kit but I feel their capabilities are masked in traditional carp marketing speak. I have no experience of other models but this is what I understand.

There seems to be no such thing as a Deeper Chirp +

If the model is followed by a + sign it signifies that it is capable of using 2 different frequencies.

If the model is followed by a +2 sign it means it uses three different frequencies,

If it has a CHIRP designation it means it uses a special technology. According to Deeper, “CHIRP sends a continuous sweep of frequencies ranging from low to high, interpreting these frequencies individually upon their return.” For the life of me, I cannot understand what this means or how it is useful. The manual seems to suggest that you choose which frequency to use. There also seems to be a feature where the frequency changes according to depth of water.

If you do not understand the relevance of frequency here is some very basic information.

An echo sounder (NEVER call them fish finders, this is totally misleading marketing speak) uses a transducer (basically a combined loud speaker and microphone combined) to generate a noise and record when an echo from that noise is received.

There is a pulse rate which is the number of times a sound is generated per second. If you put your ear to the transducer you will hear a rapid clicking noise. This is 15 time per second for all the Deepers apart from the very basic (non GPS) model which uses 10 clicks per second.

The frequency of the sound determines what gets picked up. Think of a guitar. The top string E sounds a lot different from the bottom string E. The top string is a high frequency – the bottom string is a low frequency. Here is the first indication of why frequency is important. If you hear a band playing loud music from a long way off or when a car passes playing loud music, you often hear only the boom boom boom of the base and not the rest of the music.

This is because the lower the frequency – the greater the ability to penetrate the intervening space. So in an echo sounder a low frequency could be used to penetrate weed and locate the actual bottom.

Conversely, a high frequency is quickly absorbed so it might only show you the top of the weed.  If you have a thermocline for example it could show up on a high frequency as a false bottom (but this is very rare) 

The other feature of frequency is the area is covered by the pulse. High frequencies can be focused more accurately than low frequencies. In marketing speak this is described as a narrow cone or a wide cone from which reflections are picked up.

For example in the Pro +2

675 kHz gives 7⁰ cone

240 kHz gives 20^o cone

100 kHz gives 47⁰ cone

I hope, Newmarket this helps you understand what the models mean. If I were on a budget, I would choose the PRO + . Even 10 years later and with GPS no longer working on it I still use it for feature identification and mapping (by attaching my phone and Deeper to a bait boat).

BTW give my love to beautiful Grays – I used to go to school there in the early 1960’s

Thank you so much mate that’s such a good explanation and really clears things up for me . 
Grays ? Yep wonderful place . Hated it when I first moved here but I’ve been back to a few of my old haunts recently and it’s really quite a nice clean tidy place and we are quite settled now it’s been 8 years .

Id rather live in Warsaw than Beirut let’s put it that way . 
😂 thanks again 👍🏻

[carpepecheur]

That is a very informative video Highy. 

The Deeper marketing blurb says “CHIRP sends a continuous sweep of frequencies ranging from low to high, interpreting these frequencies individually upon their return.” but in the video it seems to show that you have to select which particular frequency to use (rather than a continuous sweep of frequencies) - unless it means each individual frequency is a  very small range of frequencies.

In that video this shot shows how to select one of the three frequencies.

The reflection showing a sloping line (in the middle of the screen) is very interesting. I interpret this as an air bubble rising from the lake bed.

 

This shot shows what happens when you change frequencies. Assuming it is a continuous sounding line, each frequency shows the bottom at a different location. Which is right?

 

This shot from the video is very interesting and shows a huge parabolic reflection ("fish arch" in marketing speak) in the centre of the screen. Is it a huge fish on the bottom? Of course not. The fact that it is symmetrical indicates that it is stationery as the Deeper passes over it. I would interpret it as a vertical step, probably artificial, with some debris accumulated on the edge of the step.

There is a lot more to interpreting an echo trace than meets the eye.

[carpepecheur]

3 minutes ago, newmarket said:

Grays ? Yep wonderful place.

Id rather live in Warsaw than Beirut let’s put it that way . 

Been to both those places and would rather live in Grays but I would swop nowhere for SW France.

[Jone5y]

23 hours ago, carpepecheur said:

 

This shot from the video is very interesting and shows a huge parabolic reflection ("fish arch" in marketing speak) in the centre of the screen. Is it a huge fish on the bottom? Of course not. The fact that it is symmetrical indicates that it is stationery as the Deeper passes over it. I would interpret it as a vertical step, probably artificial, with some debris accumulated on the edge of the step.

There is a lot more to interpreting an echo trace than meets the eye.

If I'm reading that plot correctly then the x-axis represents the spatial domain rather than the temporal domain. As such I don't think you can infer that an object is stationary or not. Also, does anybody know what is actually displayed on the plot? Correlation as a function of height above the bed?

[carpepecheur]

2 hours ago, Jone5y said:

If I'm reading that plot correctly then the x-axis represents the spatial domain rather than the temporal domain. As such I don't think you can infer that an object is stationary or not. Also, does anybody know what is actually displayed on the plot? Correlation as a function of height above the bed?

The x axis represents the time taken for the transducer to send out a pulse and receive an echo. One pulse can generate multiple echoes from different targets within the three dimensional “cone” of the outgoing pulse. Theses multiple echoes from a single pulse can only be represented on the same single vertical line representing that pulse even though we do not know from what direction they were received. We are cramming three dimensional information onto a single vertical line.

The colour shown simply represents the strength of the signal received. The echo comes from a change in density in the medium through which the pulse passes. Therefore an air bubble will give a far stronger return (different colour) than a piece of weed.

The y axis is simply the accumulation of all the pulses at 15 per second intervals displayed consecutively side by side. It therefore represents time passing. It can be interpreted as distance along the sounding line whose scale is dependent on the speed of the transducer.

There is no way to distinguish between movement of the transducer and movement of the target. This can only be done by interpretation of the overall result based on experience. For example, a flat horizontal line can usually be interpreted as the bottom BUT it could equally be caused by a fish swimming at the same speed and at the same distance beneath the transducer. Experience tells us this is highly unlikely.

In answer to your specific question, “does anybody know what is actually displayed on the plot?” the answer is “no, not without more information”.

To get the best out of a Deeper, use it often and compare what is tells you with what you already know or can observe. You do not have to know the intricacies of how it works – it just helps you interpret what you see.

[Jone5y]

7 hours ago, carpepecheur said:

The x axis represents the time taken for the transducer to send out a pulse and receive an echo. One pulse can generate multiple echoes from different targets within the three dimensional “cone” of the outgoing pulse. Theses multiple echoes from a single pulse can only be represented on the same single vertical line representing that pulse even though we do not know from what direction they were received. We are cramming three dimensional information onto a single vertical line.

The colour shown simply represents the strength of the signal received. The echo comes from a change in density in the medium through which the pulse passes. Therefore an air bubble will give a far stronger return (different colour) than a piece of weed.

The y axis is simply the accumulation of all the pulses at 15 per second intervals displayed consecutively side by side. It therefore represents time passing. It can be interpreted as distance along the sounding line whose scale is dependent on the speed of the transducer.

There is no way to distinguish between movement of the transducer and movement of the target. This can only be done by interpretation of the overall result based on experience. For example, a flat horizontal line can usually be interpreted as the bottom BUT it could equally be caused by a fish swimming at the same speed and at the same distance beneath the transducer. Experience tells us this is highly unlikely.

In answer to your specific question, “does anybody know what is actually displayed on the plot?” the answer is “no, not without more information”.

To get the best out of a Deeper, use it often and compare what is tells you with what you already know or can observe. You do not have to know the intricacies of how it works – it just helps you interpret what you see.

Yes I understand how acoustic devices work as I've spent an awful lot of time analysing data collected using moored ADCPs. The two-way travel time is clearly displayed on the Y-axis in the form of distance below the reference (the surface). I was just trying to figure out if you could ever determine whether a detected object was stationary or moving, which we seem to agree that you cannot. Furthermore, I understand that the colorscale denotes the strength of the signal, but how is that determined in these deeper devices? Usually it's fairly common to use the correlation between the pulse of the signal and the return, whereby the bed can be estimated by a band of very high correlation which is indicative of a "hard return".

[carpepecheur]

11 hours ago, Jone5y said:

Yes I understand how acoustic devices work as I've spent an awful lot of time analysing data collected using moored ADCPs. The two-way travel time is clearly displayed on the Y-axis in the form of distance below the reference (the surface). I was just trying to figure out if you could ever determine whether a detected object was stationary or moving, which we seem to agree that you cannot. Furthermore, I understand that the colorscale denotes the strength of the signal, but how is that determined in these deeper devices? Usually it's fairly common to use the correlation between the pulse of the signal and the return, whereby the bed can be estimated by a band of very high correlation which is indicative of a "hard return".

Now you are singing from my hymn sheet. I grew up with sounders which burnt a trace onto sensitised paper. The stronger the pulse the more intense the burn so you knew exactly what you were seeing.

The only way I can think of to detect if a target is moving is to make sure the transducer is stationery. 

Modern digital signals allow all sorts of (unpublished) algorithms to be applied to the data so you only end up seeing what the programmer thinks you want to see. The most obvious example is the algorithm which displays a fish symbol together with the depth at which it is located.

For a start, if the fish is NOT directly below the sounding line, a greater depth will be assigned than is the case. That is fairly obvious.

It cannot distinguish between a fish and any other object of a similar density. This is easily tested by dragging your Deeper over a float suspended from the bottom. If the fish display feature is switched on, that float will register as a fish. For this reason, I NEVER have the fish display feature switched on as it can be misleading and can obscure other features.

Having said all that, the Deeper is designed for non-experts to use and, by and large, it does a fantastic job at an incredible price.

[carpepecheur]

Are there any marine biologists on this forum?

The question I would like an answer to is “how sensitive are they to sound?”

A Deeper is belting out sound pulses at various frequencies. Is this detectable by fish? Will it scare them off?

Here is a bizarre idea. If fish can detect sonar pulses, why not deploy a Deeper every time you pre-bait? That way, the fish can identify the sound of Deeper with food (as per  Pavlov’s dogs) and become attracted to the sound.

[elmoputney]

14 minutes ago, carpepecheur said:

Are there any marine biologists on this forum?

The question I would like an answer to is “how sensitive are they to sound?”

A Deeper is belting out sound pulses at various frequencies. Is this detectable by fish? Will it scare them off?

Here is a bizarre idea. If fish can detect sonar pulses, why not deploy a Deeper every time you pre-bait? That way, the fish can identify the sound of Deeper with food (as per  Pavlov’s dogs) and become attracted to the sound.

I can't answer from a science point of view, but I have left one above a feeding fish (sheeting up) for a bit while I plopped a rig on its head and within 5 minutes I had caught it, so in my mind it didn't seem overly bothered by it 😬

[carpepecheur]

Nice feedback. Thanks.