Today I tested two versions of the software for GPSMAP units. Previously I did a forced update to V16.00 which included v2.10 for LiveScope. So that is what I started with. I recorded the videos using ActiveCaptain. The videos at the link below are the unedited copies. Then on-the-water I updated to the latest version. That is 18.10 with v2.33 for Livescope. The v2.33 actually reverted to the gain tables of v2.20 that was released in GPSMAP version 17.10. Because of the time, those were the only versions I tested and based on the results I see no need for any additional testing. I do not have the market cornered on this kind of testing. What I am showing here, you can replicate. I simply suspended spark plugs with fishing line under a floating jug. If you wanted to focus on seeing your lure, you could repeat it using your favorite lure and post it here. I encourage you to do that an also to do it in a way that others could replicate it.
I had some wind blowing and the LVS32 in on the shaft of the TM, so I was not pointing directly at the targets 100% of the time. In the videos you will see rising columns of air and at times, some fish. Look at the attached sample to see how to identify the targets as they appear on screen. The names of the files tell you a lot about them. For example v16.00v2.10-Gain40.NR-Off.TVG-Off-P50T17.mp4 means the recording was done using release 16.00 containing v2.10 for the GLS10. Gain40 means the gain was manually set on 40. MR=Off means Noise Rejection was Off, TVG=Off means TVG was off P50T17 means the targets were first picked up at 50 ft, 17 seconds into the video.
https://tinyurl.com/versions1618
v16.00v2.10-Gain40.NR-Off.TVG-Off-P50T17.mp4
v16.00v2.10-Gain50.NR-Off.TVG-Off-P70T13.mp4
v16.00v2.10-Gain60.NR-Off.TVG-Off-P80T16.mp4
v16.00v2.10-Gain60.NR-Med.TVG-Off-P80T44.mp4
v18.10v2.33-Gain40.NR-Off.TVG-Off-P50T30.mp4
v18.10v2.33-Gain50.NR-Off.TVG-Off-P65T17.mp4
v18.10v2.33-Gain60.NR-Off.TVG-Off-P80T19.mp4
v18.10v2.33-Gain60.NR-Med.TVG-Off-P80T26.mp4
v18.10v2.33-Gain60.NR-Med.TVG-Med-P80T32.mp4
v18.10v2.33-Gain60.NR-Med.TVG-High-P73T12.mp4
Here are my observations from looking at the above videos.
1. There were no dead zones in either v2.10 or v2.33. It is simply a matter of pointing so that the target is in the cone.
2. At close ranges, 50 ft and less, a gain setting of 40 will show fish.
3. At a gain setting of 50 the ghost trees begin to show. A Noise Rejection of Medium does a good job eliminated them but still shows the fish.
4. A gain setting of 60 makes the ghost trees prominent but also extends the range of fish detection.
5. A TVG setting of Low to Medium did not eliminate shallow targets at range. I did not spend enough time investigating the effect of TVG. I have seen TVG on High eliminate close returns. I'm left to wonder dead zones and TVG settings.
Other Conclusions
Ghost trees, for some of you, seems to be a new phenomena. They have always been there from the original release and in every version since. You do not need a high Gain setting to see fish, but you may to see your lure. Turning the gain up, in every release will produce the ghost trees. The first resort to reduce or eliminate them is Noise Rejection. Second is TVG, but setting TVG on high can create a dead zone.
When, as I approached the targets and they disappeared from the screen, I suspected that dead zone. I noted the distances, usually 0-20 ft. So instead of approaching the target I moved to each of those distances and rotated the TM back and forth. Every time, at every distance, the targets were picked up. From this I concluded that the disappearing targets is a matter of pointing or settings. Subjectively, it seems to me that the close in cone width, 0-20 is not as wide as when I first started using LiveScope. I have no evidence of that. It just seemed that way to me.
I see no reason to suspect that if this was done on echomap Plus, UHD, or Ultra units that there would be any difference whatsoever. It is my understanding the the GLS10 box does all the sonar processing and then sends that data to the unit to display. The size of the screen and the resolution would have some effect on how it is displayed but should not change whether it is displayed.
The bottom line to all this is that I see no reason to avoid using the latest release. But it's a free country. Use whatever release you want.