Wall Wart RFI Noise Filter

Ferrite Ring Combo Pack, FT240 - 1.4" ID, 10 Rings - Mix 31(4), 61(3), 75(3), RFI Range .15-2000 MHz

FRCP-240-10
$119.95
In stock
1
Product Details
Brand: Palomar Engineers
UPC: Does not apply
MPN: FRCP-240-10
Type: NEW
Country/Region of Manufacture: United States

The Ferrite Ring Combo Pack is a convenient solution for troubleshooting RFI/EMI from unknown frequencies or multiple frequencies that require multiple suppression mixes. Included in this combo pack are ten 2.4″ OD/1.4″ ID ring toroids as follows:

Mix 75 effective from .15-10 MHz including AM Broadcast band – quantity: 3

Mix 31 effective from 1-300 MHz for general purpose – quantity: 4

Mix 61 effective from 200-2000 MHz for cell phone, WIFI, HDTV, Cable TV interference – quantity: 3

Individually wrapped and labeled with effective RFI frequency range for easy identification

The ring toroids are useful for AC/DC common mode choking with multiple turns as shown below

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AC Cable on F-240 Toroid – 7 turns

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DC Cable on F240 – 4 turns

The ring toroids can also be used on coax or signal lines as shown below:

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RG58 12 turns on FT240

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Ethernet Cable on F-240 Toroid – 7 turns

For RFI/EMI wrap as many turns as possible (usually 6-12) for higher choking (under 30 MHz). For over 25-100 MHz, 1-3 turns om Mix 61 is usually sufficient. Chokes can also be cascaded in series to offer a broader frequency range.

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Wall Wart switching DC power supplies that plug into the AC power line plug and provide DC power to laptops, routers, battery chargers, cell phone chargers, etc are a known source of broadband RFI (a.k.a dirty electricity) that effects many electrical devices including computers, radio receivers, HDTV systems, etc.  In many cases this extra RFI noise effects computer I/O speeds since they have to error correct the information packets many more times due to the noise interference causing packet errors.  A ferrite ring can often increase data throughput by reducing the error correction to normal rates.

A simple ferrite ring filter on the DC power line can help suppress the RFI noise affecting the victim device or keep the DC power cord from acting as an antenna and radiating RFI into other victim devices. This kit is also useful on laptop computer supplies, routers, cable modems, wireless phone charges, etc.

RFI WW Installation 300x288 - Wall Wart RFI Noise Filter

Installation is quick and easy: Just wrap the DC power cord through the center of the ring filter as many times as you can and reinstall.  For best results with long DC power lines, use one at the ring filter at the wall wart end (to prevent the wall wart power supply from using the DC line as an antenna) and another at the DC plug end (to prevent the electronics in the powered device from using the DC power cord as an antenna).  Typical installation is shown below:

The filter suppresses RFI in from .1-100 MHz.   Inside diameter is 3/4 inch/19 mm.

Since most households and office environments have multiple wall warts we offer the Wall Wart RFI Filter kit in bulk quantity packages.

Known RFI Generators include Roku/Sling-TV power adapter - Interference heard in the AM broadcast band
 and harmonics.
Also many ethernet Cable/DSL modems, cell phone chargers, computer power adapters have the same issue:
using the AC or DC side of the power supply as a radiating antenna.

RFI solution is to use a linear power supply, change adapters or wall wart ferrite filters