CV52 vs GT52

[TroyBoy30]

That was a full screen di shot. Are you saying the si still pings even when it's not being shown?

[smalljawer]

Just my opinion but I think you guys are way over thinking this. Again just my opinion, turn the thing on and go fishing, have fun even if you can't read what size the tire is on DI or SI

[Larry3215]

That was a full screen di shot. Are you saying the si still pings even when it's not being shown?

Thats what the evidence suggests Troy, but like I said earlier, a single screen shot like yours or the ones vik has been posting, are not 100% conclusive because we dont know for certain when the freq was for SI.

We need to see a screen shot or series of screen shots, similar to the one Leonard did with the LSS1. Run for a short while with SI/DI on the same frequency and the DI range set beyond normal so you can see where the bottom truly fades out. Change the freq on SI so it is different and note the change (or no change if vik is correct) in bottom thickness on the DI screen. Repeat on the other freq. Get screen shots.

That will establish if the DI is "pure" or if the SI pings also show up - in the form of thicker bottom return. If the DI is NOT pure, then a quick change to full screen will show if the SI keep pinging when DI is full screen - or not.

Its a simple test that anyone with a GT52 (or any other transducer) can do. Its slightly more difficult on a Striker because you cant capture screen shots on an sd card, so you need to use your phone to take a pic of the screen.

[Larry3215]

Just my opinion but I think you guys are way over thinking this. Again just my opinion, turn the thing on and go fishing, have fun even if you can't read what size the tire is on DI or SI

LOL Yup

I never can keep it straight - does that make me a geek or a nerd?

[ifishinxs]

Just my opinion but I think you guys are way over thinking this. Again just my opinion, turn the thing on and go fishing, have fun even if you can't read what size the tire is on DI or SI

Now what fun would that be?
Im with you though. Like thousands of other fisherman I turn my 93's on and go fishing. If I can see the Bottom, read temp, see fish on the screen and catch said fish I'm good to go. The CV and GT both get that job done. I still find the science behind it all fascinating and it will be fun to find out or not if the difference between the two is that much different. No matter how many screen shots are posted and no matter how much proof is shown, someone will still disagree with the findings. Leonard has taken on a tough job so all of us can learn a little more..kudos to him for taking on the challenge.

[TroyBoy30]

Thats what the evidence suggests Troy, but like I said earlier, a single screen shot like yours or the ones vik has been posting, are not 100% conclusive because we dont know for certain when the freq was for SI.

We need to see a screen shot or series of screen shots, similar to the one Leonard did with the LSS1. Run for a short while with SI/DI on the same frequency and the DI range set beyond normal so you can see where the bottom truly fades out. Change the freq on SI so it is different and note the change (or no change if vik is correct) in bottom thickness on the DI screen. Repeat on the other freq. Get screen shots.

That will establish if the DI is "pure" or if the SI pings also show up - in the form of thicker bottom return. If the DI is NOT pure, then a quick change to full screen will show if the SI keep pinging when DI is full screen - or not.

Its a simple test that anyone with a GT52 (or any other transducer) can do. Its slightly more difficult on a Striker because you cant capture screen shots on an sd card, so you need to use your phone to take a pic of the screen.

Cool. I'll ask the 'secret agent' about it as well. Everyone was tied up at I cast last week but hopefully I'll have some answers for you guys

[Larry3215]

Thanks!

I think it would be awesome if you could talk them into registering on the site - under a secrete identity of course - so we could chat back and forth. I am sure to have questions once you start posting what he says...

[TroyBoy30]

he watches but he won't answer

[LWINCHESTER2]

Ok guys. Just too many screenshots to post. Not only that but they are big bmp files and would have to be converted. So you have to go to my Google Drive to look at them. I bet you will get as tired of looking as I did making them.


https://drive.google.com/open?id=0B1...2JndXFSZklRMTQ


Files with the same first four numbers were taken at the same time
Numbers like 6060 8080 are the brightness settings and they continue until changed
The GT transducer was on 455 SideVu and 800 DownVu until 1213. Then both frequencies were the same.
Starting at 1319 Only one transducer was transmitting at a time.
I'll explain my reasoning in a subsequent post.

I'm dividing these screenshots into rounds. There will be two more rounds.

[LWINCHESTER2]

After running both units and both transducers at the same time I began to think that regardless of the frequency settings the function of each transducer might be affected by the other. Say one is on 455 and the other on 800. These elements would receive both 455 and 800 echos. Each element is designed to vibrate and produce some kind of voltage at both those frequencies. So regardless of the setting in the unit, say 455, when an 800 kHz echo hits it, it would vibrate and produce voltage. It is designed to do that at that frequency. There would be some ringing and that ringing couldn't be helpful. I could be out on a limb with this but that's why I stopped operating both at the same time.

[Randall53]

It's obvious the CV downscan is far inferior to the GT. They should have the decency to offer an exchange to those like me that ain't happy. That would at least keep down the negative customer reviews and especially referrals to others. I'm heading over to Amazon right now to post something and a few other places I know of. I've seen enough.

[Larry3215]

Im downloading them now. I can mass convert them to jpg and post smaller files if you want.

For starters - exactly how did you mount the transducers?

And - how did you do the captures - same time or on different passes?

[Larry3215]

After running both units and both transducers at the same time I began to think that regardless of the frequency settings the function of each transducer might be affected by the other. Say one is on 455 and the other on 800. These elements would receive both 455 and 800 echos. Each element is designed to vibrate and produce some kind of voltage at both those frequencies. So regardless of the setting in the unit, say 455, when an 800 kHz echo hits it, it would vibrate and produce voltage. It is designed to do that at that frequency. There would be some ringing and that ringing couldn't be helpful. I could be out on a limb with this but that's why I stopped operating both at the same time.

As long as they are on different frequencies, I doubt very much that would be an issue. After all, its done all the time on single units. I do it quite often just to reduce ghost lines. Plus, part of "low Q" is being able to reject frequencies outside the band.

Even if there was some ringing making for some interference on the screen, it would be very minute compared to what you get when they are on the same freq.

[Larry3215]

Its going to take me a while to look through these in detail, but I suspect vik will have a problem with many of them :)

In most of the simultaneous shots, the bottom detail on the CV screen is noticeably "cooler" or darker than on the GT screen shots. IIRC, he specifically wanted to see comparisons where the bottom return was of equal brightness or maybe even brighter. Increasing brightness on the CV screen may show up more detail. I think you will need to boost the Brightness settings on the CV so they are no longer equal to the GT setting.

You will probably have to increase the brightness to the point where bottom detail is washed out in order to see things sticking above the bottom line - like trees or brush.

The other very obvious thing is that the DI is not "pure" on the GT transducer on 455, but I didnt see any shots where you had both DI and SI on 800 at the same time on the GT?

[MROBIT294]

WOW! LWINCHESTER2,thank you for putting in this effort and sharing these images. All of us are extremely grateful for the time you spent in doing this experiment. I have to admit that after seeing these, I am so far disappointed in the results of the CV. I will hold my tongue as I did not see any CV images at 800...only 455. But how it can clearly miss the cover at images 1154 and 1156 is troubling to me.......could this have been improved with playing with the settings per vik's suggestions? Maybe.....I can't wait to see the rest...and I cannot believe there are even more images! Thanks again! If you ever in MA, let me know....we can spend a day on the water...and then relive it at the pub!

[Larry3215]

If I may make a suggestion - see if you can get all four screen panels so they look close to the same brightness as far as the bottom return, That will almost certainly require individual brightness settings for each individual panel. In other words, adjust the brightness so that the DI and SI on the CV look close to each other as you can and then adjust the DI and SI on the GT so they are both matched to the CV brightness. I think that would be a more fair comparison - and make vik much happier :)

Also, just to put the "pure DI on 800" thing to rest, if you could get a couple of sequential shots with DI and SI both on 800, then switch the SI to 455 and leave the DI on 800. Be sure the depth range is deep enough on the DI side to show past the fade out of the bottom return.

[Larry3215]

Sheesh! Im a jerk - posting complaints before compliments! Sorry! Yes - outstanding work and thanks for the effort!!!!!!!!!!!!!!!!!!!!!

[LWINCHESTER2]

These were all in shallow water and all CV. I had such a difficult time getting good shots in deep water I went quite shallow. The objective here was simply trying to get as best of a shot as I could and then note the settings.

https://drive.google.com/open?id=0B1...k1UMTY0X19CWW8

[Larry3215]

Very interesting pics Leonard.

A couple of things I find especially interesting...

1) Its seems pretty clear that the SI "sees" the DI pings and that the DI "sees" the SI pings when they are on the same frequency. Not only does the bottom thickness increase on DI when they are on the same frequency, but the brightness of the bottom return increases on both when they are on the same frequency. Thats going to require you to adjust the Brightness settings when you switch between having them on the same frequency and different frequencies.

2) It looks to me like the GT52 DI beam is tilted to favor the left side. That is effecting how things look on SI and what shows up or doesnt show up on the DI side.

[LWINCHESTER2]

Last ones until I get some more and that may be a few days. I want to digest this first and if I do more I want to be more focused on getting a specific image instead of a bunch to browse. You'll notice lots more GT images than CV images. That's because of the difficulty I'm having in getting good CV dpwn images. Larry make a couple of good suggestions. I need to focus on the CV on 800 kHz and I'd like to find an ideal tree running 30-50 ft deep. I believe there is enough adjustment room on the brightness and contrast to get some detail. I'm running out of adjustment for the deep water on the CV.

Round3 Shallow
https://drive.google.com/open?id=0B1...EtRd1RIQjBlZDg


Round4 Deep
https://drive.google.com/open?id=0B1...XdCWGw4MmFaVWc