Need some electronics... (2024)

So I was considering a Simrad go9 with active imaging mounted on top of my console. Then I started thinking maybe I could ditch all the analog gauges and flush mount two go7 xsr units side by side. Use one just for digital gauges mainly and the other one with the active imaging transducer(Chirp, downscan and side scan).

Now I have a few questions about this as I can't find much info on the active imaging transducer. Is there any reason to run a second transducer on the "gauge" unit like possibly a B60? I'm also wondering if the 7" screen is going to suck splitting between the chart plotter and sidescan the way it is best to use? I know these are only 500 or 600 watt units so the famous B175HW probably isn't an option.

You have to be careful with the go series of fish finders. You can only network them via NMEA2000. You can't network them with an ethernet cable. You can't share maps, sonar or radar. You have to wire them directly to the unit that you plan to always show the data.

Don't worry about displaying the gauges on one unit. You can display the engine data on the side with overlays. You mainly want just RPM and speed, just add the overlay. We almost never ever have the engine console on. Its mostly one for fish finder and one for chart while we drive. If you connect both units to the NMEA2000 backbone, you can show the engine data on either unit.

Just run the active imaging to one of the units where you always want the sonar to be displayed on. On the other unit, it would be the dedicated chart unit. If you have Navionics card, put it into that fish finder. If you have radar, connect it to the same unit for displaying charts. If you don't like the transducer, you can add another one in the future.

I highly suggest you get an external gps/compass like the Point-1 device. The compass helps prevent the screen from rotating when you are stationary. When you are moving, the fish finder can plot your direction using two gps points. When you are stationary, there are no location references since you are in one fix spot. Any changes due to small gps signal errors would cause the fish finder to lose direction and so the screen spins around and around.

SD2600 said:

I run a go7 with the 3/1 and a go9 with a b175…. I find I don’t use the 3/1 and use the 7 for chart plotting.

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Interesting, why don't you use the sidescan? Are your charts good enough to get you on the structure? Which B175 do you have?

ShadowX said:

You have to be careful with the go series of fish finders. You can only network them via NMEA2000. You can't network them with an ethernet cable. You can't share maps, sonar or radar. You have to wire them directly to the unit that you plan to always show the data.

Don't worry about displaying the gauges on one unit. You can display the engine data on the side with overlays. You mainly want just RPM and speed, just add the overlay. We almost never ever have the engine console on. Its mostly one for fish finder and one for chart while we drive. If you connect both units to the NMEA2000 backbone, you can show the engine data on either unit.

Just run the active imaging to one of the units where you always want the sonar to be displayed on. On the other unit, it would be the dedicated chart unit. If you have Navionics card, put it into that fish finder. If you have radar, connect it to the same unit for displaying charts. If you don't like the transducer, you can add another one in the future.

I highly suggest you get an external gps/compass like the Point-1 device. The compass helps prevent the screen from rotating when you are stationary. When you are moving, the fish finder can plot your direction using two gps points. When you are stationary, there are no location references since you are in one fix spot. Any changes due to small gps signal errors would cause the fish finder to lose direction and so the screen spins around and around.

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I know about the networking issues of the go7 and go9. In this case, I don't think it matters. I just want them to share engine data if possible with nmea2000.

Other than that, my main questions are on the other unit, what transducer should I use to augment the 3/1? If I could find some info on the total scan or active imaging ducers like cone angle, kw range, I might be able to figure out myself what other 2nd transducer would be helpful.

Dream to fish said:

I know about the networking issues of the go7 and go9. In this case, I don't think it matters. I just want them to share engine data if possible with nmea2000.

Other than that, my main questions are on the other unit, what transducer should I use to augment the 3/1? If I could find some info on the total scan or active imaging ducers like cone angle, kw range, I might be able to figure out myself what other 2nd transducer would be helpful.

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I would get a B175HW transducer if you fish less than 500 feet mostly. It has a wider cone angle and is good for pelagic fishing and also local bass/yellowtail. If you do a lot of deeper water rockfish (around 300-500 feet), the B175H would be better since it has a narrower cone. It really depends on what you are expecting to get from the transducer. You can use the bottom calculator from Airmar to figure out what works best for you.

Your Active Imaging Transducer specs are here in the link below. The active imaging transducer is preferred over the total scan. Totalscan was the first generation of 3 in 1 and the Active Imaging is the replacement. It has better overall specs.

Their active imaging transducer specs are written by a moron. I had to move some numbers around to make these spec make sense.

• Supports Medium and High CHIRP (83/200kHz) + 455/800kHz frequencies
• Max depth:
  • Traditional: 305 m (1000 ft) at 200 kHz
  • High Chirp and 83 kHz/Medium Chirp: DownScan: 91 m (300 ft)
  • SideScan: 91 m (300 ft) side range at 455 kHz, 46 m (150 ft) side range at 800 kHz

- Medium frequency set at a fixed 83 khz can go down probably 1000 ft on a good day when the moon is in the exact spot over horizon at 75.45 degrees in the northern hemisphere and the air humidity is exactly 72.54%. In other words, you will be lucky to get 500 - 750 feet. You definitely won't get it with the fixed frequency set at 200 khz.

- On high/medium chirp and downscan, expect around 300 feet max on a good day.

- Side scan, 300 feet side range at 455 khz and 150 feet side range at 800 khz. In terms of depth, you will be lucky it picks up anything deeper than 150 feet. Maybe the active imaging can do down to 250 feet, but I still doubt it.

According to Arbor in the link below, the 300W, 600W and 1kW Airmar single channel CHIRP transducers should work with the GO9. He knows a lot about the subject. I don't have a GO9 or any GO fishfinder. I only have Lowrance HDS and Simrad products.

ShadowX said:

I would get a B175HW transducer if you fish less than 500 feet mostly. It has a wider cone angle and is good for pelagic fishing and also local bass/yellowtail. If you do a lot of deeper water rockfish (around 300-500 feet), the B175H would be better since it has a narrower cone. It really depends on what you are expecting to get from the transducer. You can use the bottom calculator from Airmar to figure out what works best for you.

2023 Bottom Coverage Calculator | AIRMAR

Airmar calculator to help determine bottom coverage under your boat. See bottom coverage and upper water column coverage and cone angles.

www.airmar.com

Your Active Imaging Transducer specs are here in the link below. The active imaging transducer is preferred over the total scan. Totalscan was the first generation of 3 in 1 and the Active Imaging is the replacement. It has better overall specs.

Their active imaging transducer specs are written by a moron. I had to move some numbers around to make these spec make sense.

• Supports Medium and High CHIRP (83/200kHz) + 455/800kHz frequencies
• Max depth:
  • Traditional: 305 m (1000 ft) at 200 kHz
  • High Chirp and 83 kHz/Medium Chirp: DownScan: 91 m (300 ft)
  • SideScan: 91 m (300 ft) side range at 455 kHz, 46 m (150 ft) side range at 800 kHz

- Medium frequency set at a fixed 83 khz can go down probably 1000 ft on a good day when the moon is in the exact spot over horizon at 75.45 degrees in the northern hemisphere and the air humidity is exactly 72.54%. In other words, you will be lucky to get 500 - 750 feet. You definitely won't get it with the fixed frequency set at 200 khz.

- On high/medium chirp and downscan, expect around 300 feet max on a good day.

- Side scan, 300 feet side range at 455 khz and 150 feet side range at 800 khz. In terms of depth, you will be lucky it picks up anything deeper than 150 feet. Maybe the active imaging can do down to 250 feet, but I still doubt it.

Lowrance Active Imaging 3-In-1 Transom Mount Transducer - 000-14489-001

The Lowrance Active Imaging 3-IN-1 Transducer combines Active Imaging scanning sonar with a traditional Medium/High CHIRP sonar element for an easy single transducer installation. Features: Active Imaging Transducers Active

www.defender.com

According to Arbor in the link below, the 300W, 600W and 1kW Airmar single channel CHIRP transducers should work with the GO9. He knows a lot about the subject. I don't have a GO9 or any GO fishfinder. I only have Lowrance HDS and Simrad products.

Simrad Go9, 4g radar and b175hw ducer - The Hull Truth - Boating and Fishing Forum

Marine Electronics Forum - Simrad Go9, 4g radar and b175hw ducer - Needing an electronic upgrade. Does anyone use the Go9, 4g and 175hw? Any thoughts? 22ft walk around pilothouse so cal ocean fishing mostly 200ft or less. Is the hw transducer compatible with the Go9? Airmars website doesn't list...

www.thehulltruth.com

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I never fish deeper than about 300ft. I'm not looking at using a B175HW or any 1000kw transducer with a 500-600w head unit. Probably B75M or B60 50/200 I was thinking?

Thanks for those specs on the AI transducer....kind of confusing. 83/200khz, isn't this just dual channel? Most dual channel transducers are 50/200khz...what am missing here? Are they just saying that the traditional sonar in the AI transducer is 83/200khz?Medium chirp and high chirp, OK....kind of generic without telling us the freq range. Pretty sure the 455/800khz is strictly for downscan and sidescan.

There's a lot going on here and maybe a B60, B75M or B75H on the 2nd head unit isn't even going to be an improvement over the AI transducer??? I don't know if running a 1000w transducer with a go7 is possible or would offer any improvement over a 600w transducer?

Dream to fish said:

I never fish deeper than about 300ft. I'm not looking at using a B175HW or any 1000kw transducer with a 500-600w head unit. Probably B75M or B60 50/200 I was thinking?

Thanks for those specs on the AI transducer....kind of confusing. 83/200khz, isn't this just dual channel? Most dual channel transducers are 50/200khz...what am missing here? Are they just saying that the traditional sonar in the AI transducer is 83/200khz?Medium chirp and high chirp, OK....kind of generic without telling us the freq range. Pretty sure the 455/800khz is strictly for downscan and sidescan.

There's a lot going on here and maybe a B60, B75M or B75H on the 2nd head unit isn't even going to be an improvement over the AI transducer??? I don't know if running a 1000w transducer with a go7 is possible or would offer any improvement over a 600w transducer?

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You're fine with the Active Imaging transducer if you don't fish deeper than 300 feet. The advantage of the B175HW or other in-hull transducer is that you are able to track bottom and meter fish at higher speeds. The transom mounted transducer tends to wash out and lose bottom lock if its not properly mounted or if there is too much turbulence. I would suggest you try out the AI transducer first and if you decide that its not good enough, then add the Airmar transducer. At least you will have a reference point to compare.

When it comes to in-hull transducers, I'm a firm believer in getting the best that you can afford. You may not need the 1KW for now, but that may change. If you can afford it, the B175 is preferred if you decide that you want more depth range later and you don't have buy another transducer and remount it. People are more likely to change their fish finders than to change their transducers if its an in-hull transducer. Its really your own decision on what is best to your situation.

However, if you decide that 600W is good enough, I would not suggest a B60 because its a fixed frequency transducer. The B75 is a better transducer because it is designed to be chirped and chirped sonar is far superior to traditional sonar in my opinion. Going from traditional to chirp is like going from an old CRT tube to a high definition LCD monitor. You pick up more details and have better information to determine the best fishing locations.

Technically the AI transducer is dual channel, however, depending on how they cut the transducer element and design it, they can change the performance profile across different frequency bands. For instance, with traditional fixed frequency transducers, the element is designed to be optimized at that fixed frequency (narrowband). With the chirped elements, they are tuned so it works across a wider frequency band (wideband). To do that, they have to make compromises with the performance curve. If properly designed, a transducer can be used in those two frequency range. However, their performance is nowhere near a properly designed element like an Airmar B175 where its fixed at a frequency (instead of dual 83/200). With it fixed, the transducer can be designed for a larger dynamic chirp range. When the frequency is designed for dual frequencies, compromises has to be made to make it work at the two bands. As a results, the transducer is not optimized for either bands, but works well enough in both bands.

Example of a chirp transducer vs traditional. The first one is typical for chirped transducer. Its not as sensitive, but it can operate over a wider band. The second transducer operates well at the design frequency, but as you move away from the center design frequency, the performance drops off quickly. In transducer terms, its referred to as the "Q" of the transducer. The preference is for a transducer with a lower "Q" due to the wider bandwidth and less likelihood for "ringing" (which is another subject).

Hypothetically, lets say you have a fixed chirp transducer at medium frequency, its designed to work from 85 to 135 KHz. On the dual element or AI transducer, it can only be chirped from 70 to 90 KHz. They are both chirp transducers, but the non-optimized transducer has a limited useful bandwidth. That affects how much sonar power you send out and receive and therefore the performance. It also affects the sensitivity of the transducer so it may not pick up weak signals as well.

Some traditional 83 KHz transducers can be chirped also. The bandwidth is just less than a transducer that is properly designed for chirp sonar. The term "fixed" frequency is misleading. They are just designed to operate in that frequency band. Some fish finders allow you to tweak the frequency value. Lets say a transducer is designed for 83 Khz, the person can change it to 90 KHz instead. I believe the AI transducer is designed similarly. It has two bands at around 83 KHz and 200 KHz. However, its designed so it has a lower Q so that it can operate over a wider bandwidth at the two center freqeuencies.

I hope this doesn't confuse you, because its not a subject that is well understood. There is definitely a lot more details. I had a PDF file from a person who did a great job at explaining it and also how the transducers are designed to operate at two frequencies using a single element. If you want more details about that, I can dig it up. I have other more detailed information about how the chirp signals are "shaped" by the fish finder so it can be identified when the signals are reflected back from the fish or bottom of the ocean. The unique signal is sent out and when its received, the signal pattern can be used to identify when the signal was sent so the computer can calculate the signal to display on the screen.

Its interesting stuff to me because I like to understand how they work at a technical level.

Dream to fish said:

Holy smokes, that's a lot of info. Thank you for taking the time to type all of that! I agree, it costs me nothing additional to try the AI transducer first. I just don't know what the cone angle is on the chirp element. I'm wondering how narrow the cone is for searching the upper 200-300ft of water in 500ft or even deeper. Funny that you explained that freq range, because I was reading about a guy that was running the B60 with chirp and also other fixed frequencies other than the standard 50 or 200khz. On the hull truth....

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You can chirp most transducers, but they may not work as well depending on how its designed.

In the example below, if you imagine the blue line is 83 Khz and the red line is 93 KHz. If the transducer has the profile shown on the left, the power level drops about 10-15% at the 93KHz mark. Its still good enough to be useful for chirp sonars. However, on the right, if you move out the same amount, the power level drops by almost 90%. You may be driving the transducer with same energy, but its only transmitting 10% of the power of the design frequency (83 KHz).

That is one of the main reason why the chirp transducers try to make the bandwidth as wide as possible. If you make it too wide, it will also be bad because you lose efficiency. Putting in 1000W might result in only 600W transmitted if the efficiency is too low. Engineers have to figure out a profile that is the best balance.

There are other ways to achieve greater efficiency and a wider bandwidth. You have to use multiple elements and combine them together. They use filters or multiplexers to separate the signals into different bandwidths and transmit the signal to the transducer that is tuned for that range. Its kind of like a speaker system with a crossover. The low frequency is sent to the bass speaker while the high frequency is sent to the tweeters and they all work well together. Unfortunately, this adds extra cost, so that is why the units with multiple elements cost more (ie: TM150 has a single element while the B275 series has eight elements.) Some of these transducers cost upwards of $1500.

The cone angle is mainly dependent on the diameter of the transducer element. In general, the cone angle gets narrower as the diameter increases. The thickness usually determines the frequency. Thicker elements have lower frequency and thinner elements are designed for higher frequency. Typically, the cone angle for 83 KHz is around 15-25 degrees. The high frequency cone is usually around 10-15 degrees.

If you have an all in one transducer, you pretty much get what you get. You can do some experiments, but its only important if you plan to fish deep for rockfish. If the cone is too wide, fish marks around your boat could be way off. Since the transducer is limited to around 300 feet, the diameter is around 70 to 100 feet at those depths around the boat. Its good enough for most people unless you are looking for a small rock to fish on.

That is why I suggest you get familiar with the AI transducer and figure out your fishing style. Once you understand what you want out of it, that is when you can determine the best transducer for your needs. I always match the transducer to the fishing style and not the other way around. Targeting tuna, nothing beats a high-wide chirp transducer. Targeting rockfish, I prefer a standard high transducer with a narrower beam. If fishing very deep or I want to meter bottom at over 2000 feet, the only way is to go with a 50 KHz transducer.

I have the TM275LH transducer on my boat. The high setting is good for most fishing in shallow waters and to find the smaller rocks for rockfish. When hunting tuna, we switch over to the 50 KHz setting. The clarity is not as good as the high transducer, but its good enough. The 50 KHz has a wider cone, so that means we can meter more fish and hunt in deeper waters. Sometimes I just leave it in the high settings. Its a narrower cone, but the 200KHz is good at rejecting noise from air bubbles so I can get better readings on plane. I only use the transom mounted because you can't drill thru hull fittings on the boat.

Shewillbemine said:

My B75M treats me just right.

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The medium frequency transducer is a good compromise.

Unfortunately, when its mounted in the transom, there is a lot of noise from bubbles during planing speeds. When I changed to the high chirp transducer, the bubbles literally disappear. I think there is better noise rejection at the higher frequencies compared to low or medium. With your in-hull transducer, the medium chirp is a decent compromise since you pick up less bubbles during planing speeds.

I had the TM150 before and it was night and day difference compared to the TM275LH. I know its a lower power transducer, but even the fish marks at around 50 to 100 feet are a lot clearer at high chirp.

Have you seen fish marks with a high chirp transducer? Its amazing.

ShadowX said:

The medium frequency transducer is a good compromise.

Unfortunately, when its mounted in the transom, there is a lot of noise from bubbles during planing speeds. When I changed to the high chirp transducer, the bubbles literally disappear. I think there is better noise rejection at the higher frequencies compared to low or medium. With your in-hull transducer, the medium chirp is a decent compromise since you pick up less bubbles during planing speeds.

I had the TM150 before and it was night and day difference compared to the TM275LH. I know its a lower power transducer, but even the fish marks at around 50 to 100 feet are a lot clearer at high chirp.

Have you seen fish marks with a high chirp transducer? Its amazing.

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Haven't been on anyone's boat with higher chirp but I'm sure it's great. Yup, my B75M is mounted in-hull. I told Gil I never fish 1000 feet or more and it's been the right choice for me.

I doubt many people are interested in the B60 at all anymore but here is the link. I thought it was pretty interesting and has me wanting to see more. This thread doesn't show anything at 50khz I don't think, but that's the biggest plus on the B60 is the 45 degree cone angle for searching the water column. Unfortunately, that's only at 50khz.

Now a transducer I found that really has my attention....TM165HW! Apparently it's a transom mount B75HW. I wish they would actually just make the through hull version?! Yes, only 600w but 30 degree cone vs the magical B175HW with a 25 degree cone.

Dream to fish said:

I doubt many people are interested in the B60 at all anymore but here is the link. I thought it was pretty interesting and has me wanting to see more. This thread doesn't show anything at 50khz I don't think, but that's the biggest plus on the B60 is the 45 degree cone angle for searching the water column. Unfortunately, that's only at 50khz.

Now a transducer I found that really has my attention....TM165HW! Apparently it's a transom mount B75HW. I wish they would actually just make the through hull version?! Yes, only 600w but 30 degree cone vs the magical B175HW with a 25 degree cone.

Simrad GO12 XSE with B60 transducer - The Hull Truth - Boating and Fishing Forum

Marine Electronics Forum - Simrad GO12 XSE with B60 transducer - During my summer vacation I spent a few days fishing at the west coast of Norway from a friends boat. The boat has a GO12 XSE and the B60 transducer I removed from my boat when upgrading to B175H-W. My friend had used GO12 XSE at...

www.thehulltruth.com

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You can compare them with the Airmar Bottom Coverage calculator. The B60 is a 45 degree beam at Low frequency setting.

The cone angle isn't the most important factor to consider. The advantages of Chirp sonar over a conventional sonar is more important in my opinion. The cone angle would come into play based on your fishing style. If the two cone angles are close such as 25 degree vs 30 degree, the difference is not as high as you think. The "cone" is not really a precise cone. It has lobes and other characteristics similar to a RF antenna design. Its an entirely different subject that I don't want to discuss.

What you are missing is that Chirp sonars can put down a lot more sound energy than a standard sonar. With a standard sonar, a ping is sent out, then it waits a period of time and sends another ping. The ping has to return in that wait period or it would create false marks. When you are over shallow waters, the ping can hit the bottom quickly due to the short distance. You can safely set a faster ping rate to get more sound energy into the water. With greater depths, it make take longer, so you have to set a slower ping rate or you get false returns from the previous sonar pings.

With chirp sonar, that is no longer the case. The sonar would send out a sound signal that sweeps across a frequency band with a "signature". This signature is the rate or speed of the frequency change. As the sound goes down, it waits a small period of time to listen for return signals. It sends out another sonar signal with a different "signature", and waits again. This gets repeated until a number of different sonar signatures has been sent. As the sonar signal comes back, it detects the sound level on the signal, and based on the frequency and sweep "signature", it can calculate when the signal was sent out. Instead of waiting for the pings to come back in the dead time, it has about 4-5 signals out and can recreate the correct depth data based on the signatures of the signals sent. Its a HUGE improvement over a standard sonar because it can transmit 4-5x the amount of energy into the water as compared to a traditional sonar if you are over deeper waters.

As for the cone angle difference, If you do a direct look at the chart above, the 25 degree vs 30 degree isn't much of a difference in my opinion. Its a difference of 46 feet at the 500 foot depth, so you get roughly a 10% coverage increase.

To gain that, you also lose signal strength at that depth. Since the spread of a signal is the square root, you lose close to 31.6% of the power level at the 500 foot depth. If you have a 1000W transducer, the power density should be around .0259 (Watt/ft^2) with a 25 degree cone, but its down to .0177 (Watt/ft^2)with a 30 degree cone.

You have to understand that you only get an extra 46 feet at the 500 foot depth. At 300 feet, you gained 26 feet in coverage. That is only 13 feet radius around the boat. To lose about 30% of the power is not a great trade off in my opinion.

Basically you are not getting more coverage for free. You lose power density and that ends up being your ability to detect fish at the max depths.

As for the frequency, ie: 200 KHz vs 50 KHz. The 50 KHz can reach further down because of the lower attenuation. As the sound wave travels through the water column, the higher frequency signals gets attenuated (or decreases) a lot faster than lower frequency signals. That is also why the side scan sonar at 455 KHz to 800 KHz has a lot less range.

The 50 KHz will penetrate deeper, but it will lack in resolution. Any wave has frequency and wavelength. They are dependent on each other. As the frequency gets lower, the wavelength increase and vice versa. The relationship is proportional. As a result, 200 KHz signal would be able to detect a fish that is 4X smaller than a signal at 50 KHz. So instead of seeing a clear fish mark with high resolution, you see a blob if you are using 50 KHz. That may be fine if you are looking for large fish.

Another tradeoff with 50KHz to 200 KHz is noise rejection. At 50 KHz, you would tend to pick up more propeller, air bubble and other noise in that frequency range. The ocean is very noisy and lower frequency signals transmit further, so you will get more noise. With a high frequency signal, the noise that is outside the sonar's frequency band is filtered out and rejected. As a result, you see less noise in your screen. If you are on plane, it makes a difference because you will have a clean screen as opposed to one washed out with noise.

There are lots of things to consider when it comes to sonar and transducers. There is no one solution for all cases.

similar 1st world problem that I had last year.

nss evo3, upgraded to a 3-1 it was good and worked. few months later I added a tm165hw (600w) I was able to determine hard bottom from sand quite easily. now I hardly ever use 3-1 only for side scan if approaching an area I have yet to fish. don’t fish more than 300’.

ssrmr2 said:

similar 1st world problem that I had last year.

nss evo3, upgraded to a 3-1 it was good and worked. few months later I added a tm165hw (600w) I was able to determine hard bottom from sand quite easily. now I hardly ever use 3-1 only for side scan if approaching an area I have yet to fish. don’t fish more than 300’.

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Lol, yeah for sure....first world problems. I'm planning on using one go7 with a B60 and the other with the 3 in 1 AI for sidescan and downscan.

ssrmr2 said:

the 3-1 has 50/200 capability. but at 300w. you may have thought about this already but in your application would chirp be beneficial? I didn’t see a 600w wide beam w/ chirp thru hull on the airmar site unfortunately. and the 1kw units are about $1000. if I had to do it again I would get the 1kw unit and fab a special bracket to hang it on the transom

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I'm pretty sure that the 3/1 is 83/200 narrow band chirp and 455/800 for the downscan/sidescan. At the end of the day, chirp doesn't make fish bite...