Slip On Ferrite Beads

816294789 - Slip On Ferrite Beads
+3

Coax Common Mode Noise Filter - 5000 Watts, 1.8-60 MHz, up to -38dB Noise Suppression

CMNF-5000HF
$119.95
In stock
1
Product Details
MPN: CMNF-5000HF
Type: NEW
Country/Region of Manufacture: United States
Filter Power Rating (PEP watts): 5000
Choking Impedance (ohms): 400 - 5000
Common Mode Attenuation (db): 15 - 34 db
RFI Suppression Range (MHz): 1.8-60
Insertion Loss (db): .05
# Ferrite Filters: 3
Enclosure Size (inches): 4" x 4" x 4"
Typical Use:: Noise filter at radio end of coax between amplifier and antenna tuner

CMNF-5000HF for transmitter/receiver coax lines up to 5000 watts PEP - 1.8-60 MHz!

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 15-38 DB (2-5 "S" units) depending on frequency

- Simple plug & play installation: plug a short jumper from the CMNF-5000HF to your amplifier output and plug the feed line (or a jumper to your antenna tuner) into the other SO-239 CMNF-5000HF input. Either connector can be input or output. Rated at 5000 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-5000HF 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-3 prior to October 31, 2017


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 Ferrite beads are used for RF decoupling and parasitic suppression. When placed over a wire, cable or coaxial cable they suppresses common mode current flowing on the wire or wire bundle or the outside of the coax shield but does not affect the signal inside the coax cable or wire (differential current).

For RFI common mode suppression use, mix 31 is effective from 1-300 Mhz, mix 43 works from 25-300 Mhz, Mix 61 is for 200-2000 Mhz, and mix 77 favors .1-50 MHz.  These frequencies are those of the interfering signal to be eliminated, not the operating frequencies of the equipment to be protected.  See Mix Selection for other applications.

 NOW WITH QUANTITY PRICING FOR CLUB , VOLUME PURCHASERS!

Bead dimensions are shown in the picture below and in the table as A, B, C

Core Sizes - Slip On Ferrite Beads

Ferrite Bead Dimensions

 

Application Note:  Use impedances for each bead at your desired frequency to select number of beads needed for desired Z.   For example if you have a 50 ohm RG-8 coax cable and want a choking impedance of 500 ohms at 10 Mhz, you can check the FB102 column (since FB102 will pass RG-8 through its center ID) at 10Mhz and find that Mix 31 has a Z of  108 ohms/bead and Mix 43 has a Z of 91 ohms/bead.  For 500 ohms we would need 5 mix 31 beads or 6 mix 43 beads to have greater than 500 ohms.  Mix 31 has better response below 10 Mhz but above 10 Mhz mix 31 and mix 43 are very close.  If you need more Z, just use more beads in series on the cable or use more windings thru a larger ID bead (e.g. USE FB102-31 for 4 turns of RG-8X for 16X increase in Z per bead – see pictures below for examples).  Use Mix 61 for VHF and above for RFI/EMI suppression and below 30 Mhz for multi-ratio impedance transformers (baluns/ununs).  See Mix Selection for other applications.

For extra large cables use the FB400-31 which has an inside diameter of 3 inches (76mm).

Frequency Range Comparison Chart

(FB56-xx size)

FB56 xx bead mix comparison - Slip On Ferrite Beads

Multi-turn Common Mode Choking Impedance Increase Example (FB56-43)

FB56 43 Turns Impedance Graph - Slip On Ferrite Beads

Ferrite Bead relative size comparison

FB56 FB102 FB103 Relative Sizes - Slip On Ferrite Beads

Left to right sizes: FB56 (ID = .25″), FB102 (ID=.505″), FB103 (ID=.77″)

Application note for using Slip On or Snap On ferrite beads for RFI/EMI suppression: How many chokes do I need?

SLIP ON Sizes for Heliax and Coax Cable

Shown below in the table are the SLIP ON and SNAP ON products for various popular Heliax and Coax cables.  These are the correct size for making sleeve baluns.
SNAP per Coax - Slip On Ferrite Beads

Cascaded Common Mode Chokes/Line Isolators/1:1 Baluns

Here is a simple idea that is cost effective and simple to make using FB102-31 ferrite beads with RG-58 (1/4″) size cable.  Take a FB102-31 bead and insert 4 turns of RG58 spreading them out 360 degrees to minimize the capacity effects.  4 turns give 16X the choking impedance of a single bead.  So let say you are having a problem with 7 Mhz interference.  Typcial choking impedance at 7Mhz for the FB102-31 per the chart above is around 70 ohms for a single turn through the center of the bead.  With 4 turns we have 16 x 70 = 1120 ohms and with two chokes on the cable in series we would have 2240 ohms which is pretty good for $11 in beads.  See picture below for example of how these beads are used.  This winding technique is also applicable to FSB-1/2 Snap On Ferrite Split beads which will accommodate 3 turns of RG-58 coax which already has a connector attached.
Need even more choking impedance?  Use a larger diameter toroid like a FT240-43 (best above 10 Mhz) or 31 mix(best below 10 Mhz) and put 12-14 turns of RG58 on the toroid as shown below.  Our Super Choker is very similar to the toroid choke example shown below but uses multiple FT240 toroids and is useful for larger 1/2″ size cable like the RG-213, RG-8, etc.  You can order the FB102 beads and the FT-240-31 from info on this page and the FT-240-43 on the Ferrite Toroid Cores page.
RG-58 Multi-Turn Chokes/Line Isolators Examples

20131222 124620 300x180 - Slip On Ferrite Beads

RG58 4 turns on 2 FB102-31 for 2000 ohms choking impedance

20131222 125533 300x180 - Slip On Ferrite Beads

RG58 12 turns on FT240-43 for 4000-6000 ohms choking impedance
Got a question about using ferrites?  Drop us an email at Sales@Palomar-Engineers.com  and we will be glad to answer your question.

Handy Wire Size reference for ferrite bead sizes needed

 wire guage chart2 - Slip On Ferrite Beads

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Connector already on cable?  See Snap On Ferrite Beads for convenient installation on cables with connector already installed.