Wall Wart RFI Noise Filter

816294781 - Wall Wart RFI Noise Filter
+3

Coax Common Mode Noise Filter - 1500 Watts, 1.8-60 MHz, -38 dB Common Mode Noise Suppression

CMNF-1500HF
$89.95
In stock
1
Product Details
MPN: CMNF-1500HF
Type: NEW
Country/Region of Manufacture: United States
Filter Power Rating (PEP watts): 1500
Choking Impedance (ohms): 1000-6500
Common Mode Attenuation (db): 21-36 db
RFI Suppression Range (MHz): 1.8-60
Insertion Loss (db): .05
# Ferrite Filters: 5
Enclosure Size (inches): 4" x 4" x 2"
Typical Use:: Noise filter at radio end of coax between amplifier and antenna tuner

CMNF-1500HF for transmitter/receiver coax lines up to 1500 watts PEP - 1.8-60 MHz, -38 dB Common Mode Suppression

For coax feed lines with receive and transmit signals, you will love the small size, wide frequency range and excellent attenuation of common mode noise interference

- Reduces broadband common mode receiver noise* picked up on the outside of the antenna coax feed line.

- Wide frequency range works on all brands of radios and coax fed antennas from 1.8-60 MHz

- Common mode noise rejection up to 20-38 DB (3-6 "S" units) depending on frequency

- Simple plug & play installation: plug a short jumper from the CMNF-1500HF to your amplifier output and plug the feed line (or a jumper to your antenna tuner) into the other SO-239 CMNF-1500HF input. Either connector can be input or output. Rated at 1500 watts PEP.

- will work with Bias-T antenna switches and will pass DC voltage from input to output with no attenuation

* not effective for noise from AC power lines or noise received directly by antenna

Installation Note: For best results, and to reduce co-interference between choked and unchoked coax feed lines with multiple antennas, ALL antenna feed lines entering the radio room need to have a separate feed line choke particularly if they are at a different frequency then HF, like VHF or UHF.

If you use a antenna switch for multiple antennas in the 1.8-61 MHz range, place the CMNF-1500HF in the "common" line of the antenna coax switch and the antenna tuner/amplifier.

For additional common mode noise reduction, consider the CMNF-500HF (500 watts PEP) placed between the receiver and the amplifier.

Got Common Mode Noise? Not Sure - Find out now by clicking link below:

Palomar Engineers Common Mode Noise on Coax User Diagnosis Test


This product was formally named CMNF-2 prior to October 31, 2017


Save this product for later
Display prices in: USD
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