Wall Wart RFI Noise Filter

1112255371 - Wall Wart RFI Noise Filter
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MINI-CHOKER Coax Line Isolator, 500 Watts PEP, up to -38Db Common Mode Rejection, 1-61 MHz, 1:1 Unun

MC-1-500-50
$69.95
In stock
1
Product Details
Brand: Palomar Engineers
MPN: MC-1-500-50
Country/Region of Manufacture: United States
Effective Frequency Range (MHz): 1-60
PEP Power Rating (watts): 500 SSB (25% duty cycle), 250 Watts CW/FT8 (50% duty cycle)
Choking Impedance Range (ohms): 500-5000 (1-60 Mhz)
Common Mode Attenuation (db): 20-35db
Estimated Insertion Loss (db): .25 db
Input Connector Type: SO-239 female
Output Connector Connector Type: SO-239 female
Enclosure Size (LxWxH inches): 3" long, 2 in wide, 1.25" high

MINI-CHOKER(TM) Features:

- Uses proprietary Multi-Turn ferrite technology for maximum choking (up to -38 dB common mode noise rejection) and maximum bandwidth

- 500 Watts PEP, 50 ohm SO-239 connectors In/Out, 1-61 MHz (usable to 100 MHz) - AKA 1:1 UNUN

- Works for all coax fed antennas from 1.8-61 MHz (160-6 meters) - excellent for multi-band beams, verticals, dipoles, magnetic loops and highly unbalanced off center fed antennas.

- 2-5 times more common mode noise rejection, wider bandwidth and higher power then competing isolators

MINI-CHOKER feed line chokes are used to suppress common mode current carried on the outside of the coax braid which is often responsible for receiver noise and RFI in the receiver/transmitter. These chokes are very useful for suppressing RFI common mode current at the antenna feed point, at 1/2 wavelength intervals along the coax feed line and also at the entrance to the radio station.

This choke is available with a SO-239 input/output and ground/static bleeder stud (optional) for attachment to a ground rod. Use an isolator every 1/2 wavelength for the antenna operating frequency (include velocity factor in calculation). Use the ground lug option for long coax antenna feed lines (over 1/2 wavelength at the operating frequency of any antenna system in the near field of the coax).

For Higher Power needs use our MAXI-CHOKER 3KW version part# MC-1-3000 or 5KW version MC-1-5000.






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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