Wall Wart RFI Noise Filter

1725513179 - Wall Wart RFI Noise Filter
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Hybrid 9:1 Current Balun + 1:1 Current Balun in one enclosure, 1.8-61 MHz, 1.5KW PEP - BBTD, T2FD Antenna

CB-9-1-1500
$139.95
In stock
1
Product Details
MPN: CB-9-1-1500EB or TS option
Country/Region of Manufacture: USA
Input ohms/Output ohms: 50 in/450 out
Frequency Range < 2:1 SWR (MHz): 1.8-61 MHz for 1.5KW
PEP Power Rating (watts): 1.5KW
Enclosure Size: 4"x4"x 2"(1.5KW), 6"x 6" x 4"(3KW/5KW)
Weight (pounds): 3

After many requests we have created a compact, special hybrid balun for Terminated Folded Dipoles (TTFD) and Broad band Terminated Dipole/loop (BBTD) antennas. The CB-9-1-1500 is a CUBE(TM) enclosure containing a multi-core, broadband 9:1 impedance transformer (50 ohm coax input to balanced 450 ohm output) in series with a 1:1 current balun for extra common mode current choking to keep RF current off the outside of the coax braid and on the antenna where it belongs. The extra choking action also means that the coax feed line will not act as a radiator causing unnecessary RF interference (RFI). Rated for full 1500 watts PEP and 450 watts CW (ICAS). 1.8Mhz – 61 MHz.

CB-9-1-1500EB is housed in a 4” x 4” x 2” waterproof housing with SO-239 input and stainless steel eye bolts on the side for ease of connection to your wire antenna. Top eye bolt acts as an antenna hoist. Also available with top studs for post or wall mounting (Model # CB-9-1-1500TS)

Termination resistor for the antenna is a Model # TR-500-600

Many designs for BBTD antennas using 9:1 baluns at HFLINK.COM


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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