83KHZ is it important?

[wolfs4evr]

I'm not up on how 455kHz plays into the 2D sonar on a DI unit. 455 is your primary SI or DI beam or both depending on what unit you have. That I know. So the unit must be taking a slice off the 455kHz freq and using it for 2D purposes. I know it does somehow since the 859/959 are listed as Dual Beam/Switchfire units. There isn't much out there on the web either that I am finding.
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