Marcum/IR Question...

[JWB475]

Here is a question for all of you Marcum users...

I was using my Marcum on Sunday in 55 feet of water, the zoom was off.

In order to seem my lure, I had to turn the gain up. However, when I turned the gain up enough to see my lure, there was all kinds of what appeared to be interference flickering in and out in the bottom 20 feet of the screen. If I would turn the gain way up , the bottom 20 feet on the screen would be completely lit up. This interference only appeared in the bottom 20 feet, I thought it might have been some insect hatch or plankton or something like that.

I was the only person within a 1/2 mile of this spot, there were no other electronics anywhere near my Marcum, however I pushed the IR button a few times and the interference completely disapeared, and I was able to see my lure clearly.

So why did the IR clear up whatever was on the screen???? Especially when it didn't seem likely that it was caused by any other electronics?

When I have fished in shallower water (35 feet or less) I have never experienced this.

Not complaining, I love the unit, I just don't understand how the IR cleared up what was on the screen...

Any ideas?

Thanks,
JOHN

[Surface Tension]

JWB475 The MarCum's IR isn't just for dealing with interference form other sounders as you found out. Nice isn't it.
How it works you'd have to ask one of MarCum's engineers. Probably changes the way the receiver looks at the echo's profile.
All I care about is the IR on the MarCum works and I have yet to have any problems getting rid of interference from any other sounders no matter how many are around me.