Category Archives for "Electronics"

What is CHIRP Sonar?

what is chirp

​CHIRP based sonar uses a range of different frequencies to give a much clearer picture over regular sonar that will use a single frequency per burst.

Standard sonar(SOund NAvigation and Ranging) generally sends a single or fixed burst of sound waves from the transducer towards the bottom and records the time for it to return and the strength of the returned wave.

​Some objects depending on their size, shape and what they are made up of will reflect certain frequencies better than others.

If you can send multiple burst of varying frequencies you will be able to get much clearer separation and deeper penetration in term of depth.

This is effectively how CHIRP sonar works.

Most modern fish finders that have integrated CHIRP will give a much ​clearer picture than when using a single frequency beam.  

They will also perform better at deeper depths than regular sonar.

​What is CHIRP Sonar ?

​CHIRP ​(Compressed High Intensity Radar Pulse) is a more advanced type of sonar that uses multiple bursts of varying frequencies that gives better separation, deeper penetration and a higher signal-to-noise ratio.

​Traditional sonar will generally be restricted to one or two frequencies.

Certain frequencies will be reflected better off of some objects and worse off of others.

By varying the range of frequencies in a burst the returning sound waves will give you the best possible signal that the processor or head unit can utilize to transform into a picture on the screen of a fish finder.

The end result is a much crisper separation of underwater objects and a potentially higher resolution on your screen.

Traditionally 2D sonar uses 200 kHz as the most common operating frequency.

That means one continuous pulse at 200 kHz, with CHIRP sonar however there is a constant cycling through a range starting low and building to high.

The end result back to the transducer is a considerably higher amount of signals that can be combined by the head unit to give a superior read of the waters below.

​C​HIRP Fish Finder

One of the biggest advantages of a CHIRP fish finder over a standard sonar unit is that what was once a large bait ball on the sonar unit can now become much clearer even to the point where you can see individual fish.

​Before any predator chasing the bait ball would most likely have shown up as part of the bait ball but when using CHIRP sonar you can get a much clearer separation between the two.

​All of the major brands now integrate CHIRP into almost all of their units, however a lot of the base models will only run standard sonar with a fixed frequencies.

The Humminbird Helix 5 for example has several available units that support CHIRP but the base model is only available with standard sonar.

​It can often be used to run in parallel with down-imaging or side-imaging functionalities to give even clearer pictures at varying depths.

Best Fish Finder 2021 – [Buyer’s Guide]

best fish finder

Choosing the best fish finder for the money is no easy task.

With some many brands, screen sizes, transducers, and  technologies available its enough to make your head spin.

Of all of the innovations in fishing over the last several decades the fish finder has had probably the biggest impact on just how successful a lot of anglers have become.

Whilst there has been big improvements in reel technology and rod design/materials, having the ability to map out the contours and structures of the bottom has changed the game forever.

A fish finder allows the angler to peer beneath the surface and actually see what is going on down below

Being able to read and map out contours, drop offs, identify underwater structures and the exact depth and location of individual fish will considerably increase your catch rate.

Integrated GPS and map packs now allow you to map out previously never before scanned lake bottoms and record exact locations and way-points for future use.

Top Pick

The Best Fish Finder for the Money

Crystal clear Down Imaging with split screen GPS charting, 5" display and Dual Beam Sonar.

Unfortunately with so much complicated technology going on inside each unit it is not uncommon when choosing a fish finder to become confused by all of the marketing blurb and acronyms.

There are some basic features and specifications to consider before you buy a fish finder.

Once you understand these you can cut through the marketing hype and really understand what you are buying.

In our individual fish finder reviews we have made sure to point out the type of sonar and imaging used in by each fish finder brand.

A lot of websites really do not understand what they are talking about when discussing fishing sonar technologies.

Below is a no BS brief rundown of what you need to consider when choosing the best fish finder for you budget.


Most modern fish finders will have a color display. There are still cheaper units being produced with black and white screens but really your best choice will always be to opt for a full color display.

Full color displays make it much easier to distinguish between objects and are easier to read in both poor light and under strong sunshine.

Size and screen resolution are the two most important aspects of a display. 

  • Screen Size - 4 to 12 inches is the usual range depending on the manufacturer. Larger units have the ability to be split screen and will generally be much easier to read assuming the screen resolution is to a high standard.  
  • Screen Resolution - Just like on any electronic screen the higher the resolution the better and more detailed the image on a fish finder will be. If you have a large screen that can run split screen functionalities then a high resolution is most definitely required. The top brands are mostly running displays with 800×480 pixels for the best models.



A basic sonar(SOund NAvigation and Ranging) works by focusing specific frequencies of sound waves downwards from the transducer and interpreting both the strength of the returning waves and how long it took for them to be reflected off of an object below.

The most basic types of fish finders will use a single frequency as the beam of sound that they emit for their sonar.

Each frequency creates a beam of the sound emitted, the beam has a specific angle depending on the frequency.

This beam angle is commonly referred to as the cone shape. It starts narrow at the transducer and widens into a cone like pattern.

The angle of the cone is determined by the frequency.

Smaller frequencies are much more accurate, but have a narrower range of focus.

Higher frequencies have a much wider cone but suffer from reduced detail.


Put simply CHIRP(Compressed High Intensity Radar Pulse) is a type of sonar that uses a range of frequencies instead of a fixed frequency.

Some objects will reflect better when a certain frequency and others with another, by using a pulse of different frequencies you can get a much clearer picture of what is below regardless of what objects are there.

It also performs better at deeper depths than a standard 200 kHz sonar unit.

You can think of CHIRP as a more versatile and advanced version of basic sonar.

Down Imaging Sonar

It is easy to confuse down imaging sonar with regular sonar as all sonars are downward facing in a sense.

The key difference here is the word 'imaging'.

Down Imaging Sonar uses a high frequency very thin cone shaped beam of sound waves to create a very high resolution near picture like image of underwater objects.

It is almost like viewing a real-time high resolution video of what the boat is currently moving over.

Side Imaging Sonar

Although the technology has been in existence for over 50 years in naval applications it's one of the more recent innovations to be made available to the general public.

Side Imaging Sonar as the name suggests is a side ways oriented version of down imaging sonar.

Using similar high frequency super focused beans to map out the structures and objects out to the side of your boat and create a crystal clear picture like image.

Just like down imaging sonar, side imaging sonar works best at lower speeds.

Side imaging works particularly well at showing small bait fish in shallow waters.


A fish finder transducer converts electrical signals from the head unit into sound waves and then converts the reflected sound waves back into electrical signals so that the head unit can interpret them and produce images from them.

The type of transducer that you use needs to be suitable for the head unit.

Be careful when buying a fish finder as sometimes they are sold without a transducer!

There are a number of different ways to mount your transducer and this will be influenced greatly by the type of boat or kayak that you are using:

  • Thru-Hull - The most accurate type of mounting but also requires a hole to be cut in your hull and fixed permanently in place.
  • Transom Mount - Mounted directly to the transom not as good as thru-hull, requires a mounting plate, much easier to install.
  • Shoot Thru - glued or mounted on the inside of the hull without drilling a hole through it,  water temperature read out on you fish finder might stop working.

Larger boats will generally fit a thru-hull transducer so that it is permanently placed in the best spot for running a high end fish finder.

Thru-hull mounting gives you the best possible position to ensure there is little or no interruption from the hull to the sonar beam.

Smaller boats may not want to drill through the hull and are perfectly adequate to use a transom mount on.

A lot of bass boats for example will use a transom mounted transducer whereas an offshore sport fishing boat would use a thru-hull transducer.


GPS gives you a means to not only plot your route to a specific location but it also allow you to record a particular hot-spot so that you may find it easily again in the future.

They allow you to track your course over a given heading and are particularly useful when trolling.

It is also used when you are mapping or scanning a particular stretch of bottom for the first time.

Never before has an individual had the technologies available to be able to map and create their own stretches of water with such great detail using off the shelf consumer technologies.

Best Fish Finder 2021

1. Humminbird Helix 5

2. Garmin Striker 7SV

3. Lowrance HOOK2 9

4. Garmin Echomap Chirp 94SV

5. Deeper Pro+

Fish Finders

When choosing a fish finder it is really easy to get overwhelmed by all of the different types of technologies and specifications especially when the different fish finder brands can use a different name on the same type of tech.

When buying a fish finder there are a few basic specifications and features that should be considered.


A fish finders display is arguably one of it's most important features. 

Regardless of how accurate or powerful the transducer and unit is if the display is of low quality then you won't be able to determine what is going on down below.

The majority of modern displays will range from 4 to 12 inches.

But size isn't everything.

Clarity is far more important and I'd happily trade a larger screen with poor resolution for a smaller screen size on a fish finder that has a really sharp display.

Saying that smaller is not always better regardless of the size of screen you choose always make sure that the screen has a high pixel count which is what gives a much sharper resolution.

Like most things the high specification screens will come on the more expensive models so always try to get the best screen possible for your budget even if it means a slightly smaller unit.

One of the most basic choices to make is color vs black and white or monochrome.

Clearly a full color screen is going to give you the bet possible feedback.

With a full color range it is much easier to distinguish between different underwater structures and objects including fish.

They are also a lot easier to read in both poor light conditions and in very bright sunshine.

Choose that size of screen that suits your boat and always try to get the highest resolution possible that your budget will allow for.


For most larger boats a thru-hull will be the better option. The best fish finders have both down and side imaging and if you want to get the absolute best performance from them then a thru-hull transducer will give the best results possible.

Next to that will be a transom or stern mounted transducer. This are mostly added to smaller fishing boats particularly fresh water boats that do not want to drill through the hull.

Drilling through the hull is a lot easier on a larger vessel that may have much better access to the bilge area.

On smaller boats space can be a issue and you may need a specialist to fix it.

That's what makes a tramson mounted transducer so appealing as all you need is to screw on a mounting plate and then mount the transducer to it.

The plate will allow you to level the transducer which is incredibly important to getting the very best performance from it.

Sonar, Chirp or Imaging

For most anglers the choose between buying a fish finder with basic sonar, CHIRP or either down/side imaging will largely be dictated by what kind of price they are willing to go to.

You can do a hell of a lot of good fishing with just a basic sonar model once you know how to read it and understand how certain objects will be displayed on it.

But basic sonar is still basic sonar and the difference between a low end fishing sonar and even a mid-range unit is like night and day.

CHIRP gives much better clarity and object identification than a standard single frequency fishing sonar.

Imaging however really ups the ante and once you have a unit with either down-imaging or side-imaging you really will never want to go back.


I'm a big fan of GPS/chart-plotters on fish finders as they are an extra safety measure when it comes to navigation.

However, they are no substitute for basic navigational skills and knowing familiarizing yourself with the body of water that you most regularly fish on.

Having the ability to mark an exact location of a fish finder with GPS means you can no have a digital record of where you found fish.

Keeping a log of where and when you caught fish in the past can mean knowing where to fish at any given time of the year and can take a lot guess work out of the future.

Recording water temperature is also a big advantage and is something that is often over looked by a lot of anglers.

Fish Finder Brands

1. Humminbird

2. Lowrnce

3. Garmin

4. Raymarine

5. Furuno

Humminbird Helix 5 Review

​​Humminbird Helix 5 Review

If you’re a keen angler, a fish finder can help you find the best areas for catching fish.

The Helix 5 has recently been released and features a brand new landscape screen that really catches the eye.

It’s backlit, so you can easily see the screen under virtually any kind of lighting conditions. Given that there are several models of Helix 5 from which to choose, what should you buy?

​In this ​Humminbird Helix 5 Review we will take a look at all three models and point out the major differences and what type of features each provides.

​​Humminbird Helix 5 Reviews

​A GPS system is essential to a good fish finder, and this model provides a slightly improved version of the original.

This translates to better accuracy in positioning, which is always going to be helpful to any angler.

A GPS system is essential to a good fish finder, and this model provides a slightly improved version of the original. This translates to better accuracy in positioning, which is always going to be helpful to any angler.

A great display is truly essential on any fish finder, and this is where the Helix 5 models in general really shine. Their landscape orientation, backlit screens, and vivid colors make it easy to see what’s happening. As for the SI GPD model, it retains easy to read information such as water depth and temperature. It is quite large though and takes up a fair bit of the screen real estate.

In terms of software, you get the excellent UniMap, which is already loaded on the Helix 5 devices. This provides access to 3D maps of all of the major rivers, lakes, and coastlines around the country.

If you want to save your way-points, you get up to 2,500 of them, but you’ll need to push a micro-SD card into the provided slot. Given the low price of micro-SD cards, this is not a big deal. If you really want, you can also use a micro-SD card for loading other mapping software onto the Helix 5, though UniMap should do for most purposes.

The Helix 5 is one sophisticated device, and a mere 20 volts of DC power ensures that it can generate a powerful 500 watts of sonar. This will go down to a depth of at least 1,500 feet in 2D mode. If you want a super wide image, you can power it up at the cost of overall resolution. Fortunately, this Helix model allows you to run both modes at the same time for the best and most accurate results.

There are also two really useful sonar modes: Max and Clear. The Clear mode is great for when you want to find slower moving targets, such as schooling fish. The image in this mode is clear and it does a good job of filtering out all of the excess signals, such as silt.

If you want to find game fish, faster moving fish, or even geological features and objects, Max mode is the one to use. What’s very useful in this mode is the color coding of objects that allows you to see how close they are to the boat.

​If your needs don’t include 3D sonar and you want to save a bit of money, the Helix 5 DI GPS is a good option.

It may not have the 3D sonar mode of the SI model, but this is more than made up for by the quality of the landscape oriented screen.

If your needs don’t include 3D sonar and you want to save a bit of money, the Helix 5 DI GPS is a good option. It may not have the 3D sonar mode of the SI model, but this is more than made up for by the quality of the landscape oriented screen.

If you can live with the fact that the included sonar is only two dimensional, the screen will really bring the images to life.

This has the same screen as all the other Helix 5 models, and the landscape orientation makes it easy to handle and read. Moreover, the images themselves are of good resolution and have back lighting that makes them very easy to read and interpret either day or night.

The DI – or Down Imaging – feature is very powerful. It may not do side imaging, but it shows up geological features and fish from narrow to wide coverage. This feature also makes it an excellent choice for kayaking.

This model may not have the UniMap software included, but it is compatible with AutoChart. This means that you can map with sonar and then save them as a file compatible with LakeMaster software. Included GPS makes this a breeze.

​This model from Humminbird is the Helix 5 model with an included internal GPS. If you’re not in need of Down Imaging or Side Imaging, then this is well worth a look if your budget stretches to it.

This model from Humminbird is the Helix 5 model with an included internal GPS. If you’re not in need of Down Imaging or Side Imaging, then this is well worth a look if your budget stretches to it.

​For your money, you get the Helix 5 screen in landscape orientation that is orders of magnitude above many other models from other manufacturers.

This high quality, and high resolution screen makes every image pop with color and detail. It’s also backlit, just as with the other models. Making it great for viewing at any time of day or night.

The internal GPS system is what really sets this Helix 5 model apart from the competition. It is well calibrated and is also very accurate. It can show your location to within 2.5 meters. This means that you can plot a course, set up to 50 way-points per route, and go to your favorite fishing spots quickly and without fuss.

This unit lacks DI and SI, but if you don’t need to pay the extra money for the more complex models, this Helix 5 has all of the basics you’ll ever need.

Unfortunately it does not have CHIRP like the other two units. So what is CHIRP sonar exactly ?

CHIRP send a range of frequencies in a continuous burst allowing it to get much better image clarity and separation of objects.

It also has an included SD card for when you need to save map and way-point data. This unit will also save your history as a trail of breadcrumbs should you ever need to track your navigation easily.

If you want to save sonar data, you’ll need to have inserted a blank SD card. This is a bit of a limitation, but SD cards are inexpensive enough that it should not matter too much to most users. Also bear in mind that even if you invest in a transducer for DI or SO, this particular model won’t be able to display that information.

There’s a whole lot to like about the Helix 5 series from, Humminbird.

The TFT screens with 256 color capability are fantastic for seeing all of the details and for getting accurate readings.

Finally, the three models above represent great offering in their niche. Just be sure to carefully review your needs as there are some differences in terms of feature offerings.