Wall Wart RFI Noise Filter

Solar RFI/Noise Filter - 1.5" ID


Solar RFI/Noise Filter - 1.5" ID SNF-1.5

Ferric snap on bead filter effective over frequency ranges specific to solar installations including PV solar arrays, inverters, optimizers, combiners and network related control devices.

Effectively suppresses Radio Frequency Interference under 300 MHz. Use for solar installations of AC, DC, data and Ethernet cables for reducing common mode currents creating interference in electronic devices.

Two separate halves, bind together with cable ties or heat shrink.

Typical use for large bundles of positive/negative wire where diameter of all cables is < 1.5"

$49.5 In stock
Initial Permeability (@ 10KHz):1500
Max cable size - in/mm:1.394/35.4
OD (A) - in/mm:2.445/62.1
ID (B) - in/mm:1.465/37.2
Length (C) - in/mm:2.5/63.5
Z (ohms per bead - single turn 1 MHz):60
Z (ohms per bead - single turn 5 MHz):90
Z (ohms per bead - single turn 10 MHz):150
Z (ohms per bead - single turn 25 MHz):190
Z (ohms per bead - single turn 100 MHz):490
Z ohms (per bead - single turn 250 MHz):530
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

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