Wall Wart RFI Noise Filter

CUBE Feed Line Choke/Line Isolator Unun, 1.5KW, 1.8-65 MHz, -38dB Suppression

CU-1-1500SO
$109.95
In stock
1
Product Details
Brand: Palomar Engineers
Effective Frequency Range (MHz): 1.8-65 MHz
PEP Power Rating (watts): 1500
Estimated Insertion Loss (db): .10
Input Connector Type: SO-239 female
Output Connector Connector Type: SO-239 female
Ground Connector (Y/N): none
Enclosure Size (LxWxH inches): 4 x 4 x 2

1500 Watt Rated 1:1 CUBE™ Unun

Th CU-1-1500 unun is useful as common mode feed line chokes or coax to antenna interfaces. SO-239 output models can also be used with balanced antennas if a short coax cable “pigtail” is used on the output and connected to the antenna. Rated 1500 Watts PEP from 1.8-61 MHz. Use as line isolator, antenna interface, or as a common mode choke to keep RF on the antenna and off the outside of the coax braid. Much more effective then our sleeve feed line chokes due to our exclusive Multimix(TM) multi-core topology using high permeability ferrite cores which provides a high choking impedance over a broad frequency range. Typical common mode suppression is 20-38 dB (up to 6 "S" units) from 1.8-61 MHz reduces common mode current! For most effective results, use 1 choke at the antenna and another at the radio. Helps reduce noise floor too by choking off common mode neighborhood noise picked up on outside of coax braid.


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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