Slip On Ferrite Beads

3854321636 - Slip On Ferrite Beads
+3

Bullet 50:200 (4:1) HF Unun, 1.8-61 MHz, 100/500/1500 Watts, End Fed OCF Antennas

Bullet-4U-100
$69.95
In stock
1
Product Details
Brand: Palomar Enginees
UPC: Does not apply
MPN: Bullet-4U-100/500/1500
Type: NEW
Country/Region of Manufacture: USA

The “Bullet” End Fed OCF Antenna Matcher - 100/500/1500 Watts PEP/Digital

The key to end fed OCF antenna success is the matching network interface between the wire antenna and the feed line choke on the coax. Palomar Engineers employs a dual port ferrite matching system that offers wide bandwidth (1.8-61 MHz), and a 100 watt PEP power rating.

The antenna can be used as a sloper, “L” with a vertical section and a longer horizontal section, or as a horizontal or sloper antenna between two trees or supports. Great antenna for portable operations like NPOTA, SOTA, Field Day, etc., or for permanent installations like installing in an attic, under the eaves of a house, along a fence, etc. This is a short, effective and easy-to-hide antenna which gives a good account of itself on -80-6 (95' wire), 40-6 (55' wire) or 20-6 (25' wire) meter bands.

We sell the Bullet-4U-100 separately so you can add you own wire type and length (see table of suggested lengths below) or you can purchase a complete antenna system including wire and end insulator. Remember you also need a feed line choke like the easy adjustable snap on SOFLC.

If you need a higher power 4:1 unun for your OCF end fed antenna, check out the Bullet-4U-500 or Bullet-4U-1500.

Use a good quality 50 ohm cable such as RG-8X or similar as that size allows multiple (5-6 recommended) turns thru the feed line choke. The Bullet-4U-100 matching unit is rated for 100 watts PEP for SSB and 100 watts for CW/FT8. If the matching unit becomes warm to the touch after transmitting at high power, reduce the power output or the internal matching unit may become damaged.


NOTE: We rate our Bullet baluns (and ununs) VERY conservatively with a 50% duty cycle as used with digital (FT8) modes. Some manufacturers selling low cost baluns may use a 5% duty cycle for their PEP rating to make it appear you get a higher rated balun for a lower price, but you may in fact be getting be getting less. Their 1500 watts PEP really means 75 watts continuous or 150 watts at a 50% duty cycle compared to our 250 watts at 50% duty cycle. Our baluns typically cover a larger frequency range under 2:1 SWR which make your transceiver happy and probably will last longer with less electrical stress.

Remember we over engineer our products, to out perform our competition - just compare the weight of our products to theirs and you will know we put much more into our products so you don't have to worry about power saturation failure at a critical moment.

Save this product for later
Display prices in: USD
 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

 ————————————————–/———————————————————

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