AM Broadcast RFI Kits

Fish Finder-Sonar-Depth Finder RFI Kit

SKU RFI-FF
$44.95
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Fish Finder-Sonar-Depth Finder RFI Kit
Product Details
Brand: Palomar Engneers
UPC: Does not apply
MPN: RFI-FF
Type: New
Country/Region of Manufacture: United States

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.

When considering solutions for AM broadcast (550 Khz – 1.8 Mhz) you should consider Mix 77 ferrites available in a variety of shapes and sizes.  Choose a size to give the maximum number of turns of the affected wire or cable.

AM broadcast transmits on a low frequency with large antennas.  Consequently it takes a large antenna to receive the signals.  Typical “antennas” are AC house wiring, phone lines, long satellite or cable TV cables, DSL/CAT5 lines running between rooms, etc.  The device wires that connect to these  “antennas” need to be choked with as many turns through the ferrite as possible.  Some installation examples are shown below on this page.

For AC/ DC power cords and coax cables the F240-77 (2.4″ OD, 1.4″ ID) “Donut” toroid is the most popular.  Also available are smaller toroid donuts and Mix 77 beads. Shown below is a graph with 8, 10, and 12 turns through the toroid – obviously more turns has higher choking impedance.  Mix 77 toroid products are HERE and Mix 77 small beads (for small wires) are HERE

F240 77 Turns Comparison 1024x648 - AM Broadcast RFI Kits

F240-77 Turns Comparison from .1 – 8.1 Mhz

Shown below is a graph of frequency response verses choking magnitude for a F240-77 in the AM Broadcast band for a 12 turn coil around the toroid. (Same info as above but different frequency range).

AM Band Choking Graph F240 77 1024x648 - AM Broadcast RFI Kits

F240-77 Choking Impedance in AM Broadcast Band

 

 

Typical Installations for Donut/Ring Toroids

20131210 114716 150x150 - AM Broadcast RFI Kits

AC Cable on F-240 Toroid – 6 turns

20131210 115137 150x150 - AM Broadcast RFI Kits

Ethernet Cable on F-240 Toroid – 7 turns

20131222 125533 150x150 - AM Broadcast RFI Kits

Audio or Mic cable on F240- 12 turns

 

 Extra Mix 75 Snap On Beads  HERE – VERY effective for AM Broadcast RFI