Wall Wart RFI Noise Filter

1725390966 - Wall Wart RFI Noise Filter
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Hybrid 4:1 Balun + 1:1 Current Balun in one enclosure, 1.8-61 MHz, 1.5/5KW PEP - Loop, OCF Antennas

CB-4-1-1500EB
$139.95
In stock
1
Product Details
MPN: CB-4-1-1500TS/EB , CB-4-1-5000TS/EB
Country/Region of Manufacture: USA
Input ohms/Output ohms: 50 in/200 out
Frequency Range < 2:1 SWR (MHz): 1.8-61 MHz for 1.5KW
PEP Power Rating (watts): 1.5KW/5KW
Input Connector: UHF SO-239
Output Connector(s): Side Eyeboplts (EB) or Top Studs (TS)
Enclosure Size: 4"x4"x 2"(1.5KW), 4"x 4" x 4"(5KW)
Weight (pounds): 2# (1.5KW), 4# (5KW)
Antenna Compatability: OCF, Loop, BBTD, T2FD, ZEPP


After many requests we have created a compact, special balun for Off Center Fed (OCF) , loop (Skyloop or Delta loop) , BBTD, T2FD, folded dipoles antennas. The CB-4-1-1500 is a CUBE(TM) enclosure containing a multi-core, broadband 4:1 impedance transformer 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 1000 watts CW (ICAS). 1.8Mhz – 61 MHz.

CB-4-1-1500 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.

5KW are in 4" x 4" x 4" enclosure. 1.5KW is 2 pounds, 5KW is 4 pounds.

For an 80 meter OCF antennas we recommend a (95 feet/79.5% and 40 feet/29.5% offset for best all band results. If you use 66%/34% offset, do not use on 15 meters as the impedance mismatch may damage the balun at high power levels. Loop antennas should be cut for 1005/F(MHz) in total length, where F (MHz) is the lowest frequency to be used. For 3.5MHz this equates to 288 feet.

We highly recommend a feed line choke (MC-1-3000) or coax noise filter (CMNF-1500) at the radio end of the coax feed line to reduce common mode noise picked up by the coax braid.

CB-4-1-5000EB/TS are custom made to order - please allow 7-10 days ARO before ship.

Customer testimonial:

Callsign: NE5U Your CB-4-1500 +1:1 Choke made my homebrew, hail mary, 3 times folded 75m resonant attic dipole into a functional antenna from 6m to 160m. Most bands I can operate with no RFI. I've installed ferrites at all of the usual locations but still have some problem bands. Considering that the antenna is, at best, an NVIS antenna, I have made a lot of DX contacts (SSB, FT8 and other digital modes, and CW). Happy customer here. 73

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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