Slip On Ferrite Beads

3938088187 - Slip On Ferrite Beads
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Bullet 50:450 (9:1) HF Unun, 1.8-61 MHz, 100 Watts, End Fed Antennas

Bullet-9U-100
$69.95
In stock
1
Product Details
Brand: Palomar Enginees
MPN: Bullet-9U-100
Type: NEW
Country/Region of Manufacture: USA

The “Bullet” End Fed Long Wire Antenna Matcher - 100 Watts PEP/Digital

The key to end fed antenna success is the matching network interface between the long wire antenna and the coax feed line and feed line choke at the transceiver. Palomar Engineers employs a dual core matching system that offers wide bandwidth (1.8-61 MHz), 100 watt PEP rating, and a connection for a counterpoise or ground if desired.

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 40-6 meter bands.


We sell the Bullet 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 feedline choke like the easy adjustable snap on SOFLC.

For best results we recommend that the coax feed line be at least 1/4 wavelength on the lowest operating frequency since the coax braid is used as a counterpoise if you don’t use the external counterpoise terminal on the matching unit. We also recommend a feed line choke at the end of the coax feed line near the radio to prevent RFI common mode current from interfering with the radio.

Suggested wire lengths (measured from Bullet feed point):

Bands Covered (meters)

Wire Length (feet)

Minimum Coax Length (feet)

40-6

41

25





80-6 with tuner

71

50

80-8 (wider on 80)

111

100

160-6

155

100

For those operators who like to experiment, the following lengths of wire can also be used: 49, 55, 77, 92, 102, 141-148, 171, 203, 218, 268 (feet).

If you need a higher power 9:1 unun for your end fed antenna, check out the Bullet-9U-500,SBullet-9U-1500SBullet-9U-1500 or the CU-9-5000 (5KW PEP)

Installation

For best results raise the Bullet matching unit as high as possible (use a tree or vertical support) and then extend the antenna wire horizontally or as an “L” (horizontal with vertical end drop). The antenna may also be deployed as a sloper with the Bullet matching unit at the top (best) with the wire sloping toward the ground (with the end high enough to avoid contact by humans or animals), or at the bottom of the sloper with the antenna wire rising to a higher point (see typical configurations below).

Antenna Length Modifications: For best results, chose a length from the table above as these lengths will form a non-resonant antenna for the amateur bands indicated.The antenna length should NOT be ¼, ½ wavelength on any frequency that you transmit as the impedance will be very high (or low) and will not transfer through the matching unit at a favorable impedance to your antenna tuner.The theory of the antenna length is to make the antenna non-resonant on any amateur band so that the impedance at the antenna side of the matching unit is in the range of 200-600 ohms and when divided by 9 will be in the range of your transceiver antenna tuner.

Any length of 50/75 ohm feed line ok (over 35 feet minimum) but longer feed lines over 50 feet may show reduced SWR on some bands due to soil conductivity, nearby objects, etc. Due to local ground conditions, antenna height and feed line length, SWR may vary and an antenna tuner may be required or some bands to bring SWR at end of feed line to acceptable levels.Use of one or more ¼ wavelength counterpoise(s) connected to the ground post of the matching unit may also improve antenna efficiency and reduce SWR on certain bands.The first counterpoise should be installed under the horizontal portion of the antenna for best results

Use a good quality 50/72 ohm cable adequate for the power level of your station.The Bullet-9U-100 matching unit is rated for 100 watts PEP for SSB and 100 watts for 100 watts 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.

Testimonial

Hello, Bob:

I am e-mailing to tell you how impressed I am with the Bullet-9U I received on 3/11/19. I immediately threw a 44 foot wire across my tile roof (in Florida) and began to tune up on 20 meters CW. I was running only about 15 watts to tune the wire and immediately, a station in Ontario came back with "579".) I got down to a 1.5:1 match and increased power to 100 watts. I heard a ham in Croatia calling CQ and got a "599" from him. Switched to 40 meters and before I could tune up, with about a 5:1 SWR, I was called by a ham in Cuba with a 579! And this with the bands in "poor" condition. I never expected such fantastic results. Thank you for a great product.

Dennis Lazar
W4DNN

Note: See Dennis's QST article in February 2020 QST Magazine for more details.

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 baluns to theirs and you will know we put much more into our products so you don't have to worry about failure at a critical moment.

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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.

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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.