carpepecheur

I can assure you Highy, that you can never be certain what the reflections you see on the screen of an echo sounder represent. I spent a substantial part of my working life hunched over a very expensive echo sounder running exactly the same sounding lines year after year. I can say that I have picked up many sharks on an echo sounder. Sharks do not have a swim bladder. How do I know they were sharks? … I could see them! A good indication of a potential fish are the parabolic reflections (or fish arcs in marketing speak) you get as you move over a fish and the measured distance to it changes. The thickness of the line forming the arc can indicate the size of the fish. You only get an echo from a change in density. The strength of the echo depends on how much the signal has been attenuated (absorbed) during its path, the degree of density change it reflects off, and the angle at which it strikes it. It helps to understand the physics of sound. A low frequency (wide angle) will penetrate further than a high frequency (narrow beam). So a low frequency helps locate a solid bottom beneath silt whereas a high frequency will show weed better. The science is very simple. Understanding the results is incredibly complicated. There is no substitute for experience but the Deeper software does a pretty good job at interpreting the results for the average layman. I assumed your post was Deeper's reply but, having read it, I still can't get my head around CHIRP technology.

Nice feedback. Thanks.

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.

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 Modern digital signals allow all sorts of (unpublished) algorithms to be applied to the data so you only end up seeing what the programmer thinks you want to see.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.

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.

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

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.

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 20o 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

One point about attaching your Deeper to a boat is that, if you put your phone on the bait boat, you can go well beyond the range of the Deeper Wi-Fi.. This is useful on big waters. When you are sailing your sounding lines, you get a much clearer and accurate picture if you try and steer them at right angles to anticipated contours. This would typically be at right angles to the bank rather than parallel to it.

I only use my Deeper with a boat. I attach it with a spare piece of 200lb mono tied to a clip which attaches to the handle.

For the last 10 years or so, I have been using a Lafuma reclining chair. It is not meant for carp fishing and weighs in at a hefty 7.2 kg BUT you can sit in a completely relaxed, reclined position, then when you get a bite, push your legs out and you swing forward (almost propelled into a standing position) and take care of business. This is their web site. There are a lot of bargains if you shop around on the net. https://www.lafuma-furniture.co.uk/relaxation-chair-rsxa-clip-batyline-lac-tubing-basalte-uk.html Fortunately, there is no camouflage version

I wouldn’t doubt that story. I fish a lake near me that was stuffed with crayfish. They make a brilliant bait and crushed crayfish makes a brilliant ground bait. Mostly, I put down traps and took a load home to eat. Then about three years ago, they completely disappeared and you couldn’t catch a single one. They have only just started to slowly return.

If you microwave your normal boilie mix (instead of boiling it) it will make your baits pop ups.

I don't fish pop ups very often but I did make a slo mo video of a set up based on the "Bald Rig". It gives an extremely active hook action. I just chuck it in here as an idea some may find interesting.

You are not supposed to eat them!

There are plenty of safeguards for the less well off in France. Additionally, if you have a long lasting condition requiring repeat visits, all your health care is free. I feel for the many people in UK who rely on foodbanks just to exist (although Rich Sunac thinks they are just having a cash flow problem!!!). Unfortunately, as a result of recent political decisions, there are a lot more cost to come through yet. The sooner the current muppet show is closed down, the better.

In France the health system seems to work well but very different from UK. Every procedure has a government tariff which you must pay, even for a visit to the doctor. If you qualify, i.e. you are a French national or legally resident, you get a health card which permits you to claim back 75% of costs. Most people take out an insurance policy to cover the extra 25%. This way you have a very good idea of the value of health care. It can be a strange feeling handing over a wodge of fivers to the doctor at the end of your consultation but these days’ payments are automated on production of your health card and no money changes hands. This prevents health fraud because, before any major procedure, you have to show means of payment i.e. your health card. Doctor appointments, are made by phone, internet or visiting the doctor’s receptionist, sometimes for the same day but often for the next day. If you need a specialist, you can choose which one to visit at a hospital or clinic of your choice. I get a regular check up every three months and am allocated 30 minutes of the doctor’s time (although it can often over run). So, when your MP starts making excuses for the NHS and proposing privatisation as the solution, point them at France.

Well said. Had we stayed in the EU this would not be allowed to happen under the Waterways Framework Directive (which we played a large part in formulating). Now we (or rather the ERG) have taken back control and can patronise whom they like. I have a sneaky feeling we are already too far down that road but I have signed the petition anyway. WE need to be heard not humiliated.

I love that Elmo. It is obviously an allegory for Enoch Powel’s Birmingham speech where he was brutally demolished by the media. He never ever said “rivers of blood”. He only quoted from a poem by the ancient Roman poet Virigil, referring to blood in the River Tiber in Rome. His media massacre was so comprehensive however that now, 60 years later, he is only remembered for something he never said. He had a brilliant mind which made people afraid of him and he is probably the best Prime Minister we never had. I totally agree. I think the reason that is possible is that none of the posters on this thread are pushing a party line in the manner of supporting a football team. I have a theory that all party politics (the mechanism for exerting political will) should be made illegal. Alongside this I would ban all forms of taxation (the source of political power) and replace it with an automatic levy on every single pound whenever it is withdrawn from a sterling account. This is the cheapest way to raise government finance without an opportunity to avoid it ... and would be much less expensive for plebs like me. I think "rivers of poo" is a good description of politics today.

I totally agree. As Miliband said today, we need a statesman not a party leader. Best on the horizon at the moment is Tom Tugendhat.

It does bring a whole new meaning to the game of poo sticks.

Yes, disruption to the supply chain was widely predicted before Brexit but, had UK stayed in the EU, the pollution of rivers would not have been allowed and nobody wanted the EU telling them what they can and can't do!

Yes, as well as exploring new waters , that is a good way to use it. I am almost persuaded to stick with the Pro +. I was just curious to find out if anyone has shelled out more than £100 for a chirp version and if they found any extra benefits The Deeper makes a complex technology really easy to use. The Gemini ARC lead system makes a simple technology really complicated.

I think you are quoting the cone angle rather than the frequency Elmo but I understand your comment. However it is not quite what I was getting at. A CHIRP pulse, instead of sending out a single frequency pulse, sends out a pulse which changes in frequency during the pulse. I used a lot of echo sounders in my working life but I retired before CHIRP technology became available. My query is really to understand the difference between a CHIRP sounding and a single frequency sounding. Over the depths we carp anglers are likely to use does it make much difference? I understand that the CHIRP can be switched on or off. Has anyone with one of these new fangled gizmos tried this and was there a practical difference?

Thanks for that Carpbell. I noticed the shallow spec in the marketing blurb but I seem to only fish deep water around here. Very interested to hear experience of actual use especially if someone has used new and old versions.