Side imaging overrated

[pawpaw]

Got it. You can definitely see it. Your settings are spot on in that shot. VERY NICE!!

[Wayne P.]

1 hour ago, Goose52 said:

I was on the lake today, saw this SI image, thought of this thread, and got a screen shot.  This is a Helix 10 with the HDSI transducer. Depth is only 12 feet but you can see a bunch of stuff on each side, including spawning beds.  When I had my HB 798 with the standard compact transducer I would not have seen this much detail, this sharp, but I would have seen enough to know if I wanted to work over that area.

So, for me, and with the equipment that I've had, I'd say the last 5 years that I've been using SI has indeed let me see more stuff...and  catch more fish...

Other than speed what was the difference between the top half and bottom half?

You have RFI on the bottom half.

[pawpaw]

13 minutes ago, Wayne P. said:

Other than speed what was the difference between the top half and bottom half?

You have RFI on the bottom half.

Moved from the trolling motor to big motor to pick up speed?

[Goose52]

You guys have me re-thinking about what exactly I was doing when I hit the "mark" button !

I was drifting and saw some return - I cranked on the speed from the TM and got a better return, then probably killed (or reduced power on) the TM when I decided to get a screen grab and started reaching for the "mark" button. So, the upper part is probably with the TM off or reduced power but still "coasting" and registering speed.

If that IS RFI (and if Wayne says it is then I guess it is!) and not just a diminished return due to too slow a speed...then I need to play with this some on the water. My sonar and TM are on the same battery. Perhaps I need to sometime power the sonar off my 7AH battery while in the boat to see if there's a difference. This is puzzling to me as I've had very sharp SI images when I'm on the TM (albeit at lower power levels). Wayne, do think there is a TM power level threshold above which I've got the RFI?  I really "goosed" the TM when I came out of the drift and perhaps I was above that RFI threshold ?

BTW - there is no " big motor" - only the the TM !

[Wayne P.]

22 minutes ago, Goose52 said:

You guys have me re-thinking about what exactly I was doing when I hit the "mark" button !

I was drifting and saw some return - I cranked on the speed from the TM and got a better return, then probably killed (or reduced power on) the TM when I decided to get a screen grab and started reaching for the "mark" button. So, the upper part is probably with the TM off or reduced power but still "coasting" and registering speed.

If that IS RFI (and if Wayne says it is then I guess it is!) and not just a diminished return due to too slow a speed...then I need to play with this some on the water. My sonar and TM are on the same battery. Perhaps I need to sometime power the sonar off my 7AH battery while in the boat to see if there's a difference. This is puzzling to me as I've had very sharp SI images when I'm on the TM (albeit at lower power levels). Wayne, do think there is a TM power level threshold above which I've got the RFI?  I really "goosed" the TM when I came out of the drift and perhaps I was above that RFI threshold ?

BTW - there is no " big motor" - only the the TM !

Whatever you were doing last has no RFI as evidenced by the sharper upper part of the image. SI records from the top to the bottom of the display--current data is at the top of the screen.

Typically when you run a variable speed trolling motor, you can eliminate RFI at the highest speed setting since the pulsing circuit is bypassed. But at any range of speed settings, the RFI frequency can be a little different and may or may not affect the sonar frequency.

Connecting the unit power to the trolling motor power is one thing to avoid.

BUT, having separate power is not a cure-all either. Just something you have to deal with if you experience that issue. There is no "one size fits all" to cure RFI. Each installation is unique.

 

[Goose52]

7 minutes ago, Wayne P. said:

Whatever you were doing last has no RFI as evidenced by the sharper upper part of the image. SI records from the top to the bottom of the display--current data is at the top of the screen.

Typically when you run a variable speed trolling motor, you can eliminate RFI at the highest speed setting since the pulsing circuit is bypassed. But at any range of speed settings, the RFI frequency can be a little different and may or may not affect the sonar frequency.

Connecting the unit power to the trolling motor power is one thing to avoid.

BUT, having separate power is not a cure-all either. Just something you have to deal with if you experience that issue. There is no "one size fits all" to cure RFI. Each installation is unique.

 

Thanks Wayne. "Catching" is starting to slow down a bit here so it looks like I can spend some time on the water playing with different TM power levels. I generally use fairly low power levels when scanning the sonar and only use the higher power levels when motoring from place to place so I don't think the RFI in the above screen shot is going to be a big issue. 

I knew that powering both the TM and sonar from the same battery is generally not recommended, but I do it for simplicity since the boat in question is a canoe and there are packaging considerations !