Fish Finder – Sonar RFI Kit
Fish Finders/Sonar units can cause RFI “noise” in other electronic devices on a boat including audio and video systems, radar, SSB, wind/speed/depth instruments, etc. Likewise other electronic devices can also interfere with the fish finder and cause erroneous depth/temperature readings.
Palomar Engineers has developed a simple to install fish finder/sonar RFI suppression kit to solve the RFI noise problem aboard recreational and commercial boats.
Just slip a split bead on the transducer cable (1" ID) and use the 5 1/2" ID split beads on the fish finder/sonar readout unit transducer input and DC cables. Use the extra ferrites on other equipment needing protection like the Radar, radio, etc.
12:1 Ununs are useful between coax and long wires with a load impedance near 600 ohms like a beverage antenna. Shortwave listener antennas also can benefit with the 12:1 unun and it may provide a better match than 9:1 ununs – this means quieter noise levels and stronger signals so you can hear distance stations easier.