A ferrite ring or two wrapped several times thru the XDCR cable often helps...

I used 2 of these stacked & wrapped about 9 turns of cable for my SI and DI units on the bow.

I used the "31 mix" because I use 800 kHz more than many do and wanted to effect the higher frequencies as little as possible.

https://www.mouser.com/ProductDetail...te/2631803802/

The "77 mix" may work better for you, as their is "no magical formula"...

https://www.mouser.com/productdetail...te/5977003801/



G'Luck,
RAS