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 Bullet-9LF employs a dual core matching system that offers wide bandwidth down to 20 KHz (.02-31 MHz), 500 watt PEP rating, and a connection for a counterpoise or ground if desired. longer horizontal section, or as a random horizontal antenna between two trees or supports. Our network matching network is called the “Bullet” because of it shape and its effectiveness at taking down or contacting distant (DX) stations all over the world under the right conditions. The Bullet uses all stainless steel connectors and a dual core ferrite 9:1 unun for higher power rating then many competitive products. 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. 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. The BA-58 (slip on) or Kit 105 (snap on) sleeve chokes or simply a EFFLC choke with 10 turns of the coax line on RG-8X (1/4″ cable) typically used for low power operations. Bands Covered (meters) Wire Length (feet) Minimum Coax Length (feet) 40-30-20-15 35-43, 49-63, 70-85 35 40-30-20-17 35-45, 54-64, 67-77 35 40-30-20-17-15-12-10 38-44, 55, 60, 68-73 50 80-40-30-20-17-15-12-10 68-73, 85, 92, 102, 120-125 65 160-80-40-30-20-17-15-12-10 135, 141, 173, 203 130 If you run more than 500 watts PEP and need a high power 9:1 unun for your end fed antenna, check out the 1-7.5KW PEP ununs on the 9:1 impedance transformer page in our website at http://Palomar-Engineers.com . 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). Additional Typical Antenna Configurations: 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-80 matching unit is rated for 500 watts PEP for SSB and 150 watts continuous carrier for AM, FM, digital modes, or 375 watts CW.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: due to the nature of antenna systems and the modifications many users perform and the transmitter power levels that may be applied higher then the specifications, the antenna systems are NOT RETURNABLE unless they are unused, in the original packing with the original invoice and a return request is made withing 30 days of original purchase.
The “Bullet” End Fed Antenna Matcher - Low Frequency Model Bullet-9LF, Ham and Short Wave Listener
Suggested wire lengths for 1-31 Mhz operation (measured from Bullet wire point):
$129.95
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
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)
Multi-turn Common Mode Choking Impedance Increase Example (FB56-43)
Ferrite Bead relative size comparison
Left to right sizes: FB56 (ID = .25″), FB102 (ID=.505″), FB103 (ID=.77″)
SLIP ON Sizes for Heliax and Coax Cable
Cascaded Common Mode Chokes/Line Isolators/1:1 Baluns
 RG58 4 turns on 2 FB102-31 for 2000 ohms choking impedance |
 RG58 12 turns on FT240-43 for 4000-6000 ohms choking impedance |
Handy Wire Size reference for ferrite bead sizes needed
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Connector already on cable? See Snap On Ferrite Beads for convenient installation on cables with connector already installed.