Wall Wart RFI Noise Filter

Coax Static Bleeder

SB-1
$21.95
In stock
1
Product Details
Brand: Palomar Engineers
UPC: Does not apply
MPN: SB-1
Type: NEW
Country/Region of Manufacture: United States

Model SB-1 is a static bleeder meant for 50 or 75 ohm coax line. It is rated from 1-150 Mhz at 1.5KW with a maximum SWR of 5:1 on the line. The bleeder is used on a coax “T” in line with the coax transmission line as shown in the picture below.

20141004 125359 300x168 - Wall Wart RFI Noise Filter

SB-1 Coax Static Bleeder installed on coax “T” connector

To use procure a coax “T” and a male to male connector. Connect the SB-1 to the male to male connector and thence to the coax “T”. Static voltages are bled off from the center conductor to the outside conductor (braid of the coax). At the entrance to your radio station ensure that the outside conductor of the coax transmission line is grounded so as to provide a sink for the static electricity on the antenna center conductor.

The SB-1 static bleeder is usually installed near the radio shack entrance on the antenna side of any 1:1 baluns/line isolators (between isolator and radio) if used.

the connector is a male PL-259 and will fit into a SO-239 (female) or "T" with female counterpart to the PL-259. Small, convenient, effective and easy to install! "T" connector shown in picture NOT included.

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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