End Fed Off Center Fed Antenna
Need a high performance, multi-band, stealthy antenna system that is easy to setup and use? Get the Bullet antenna matcher with the antenna wire, insulator and feed line choke all in one convenient package (great for HOA restricted areas, camping and portable operations, etc.)
Why is this end fed OCF antenna a better choice than and End Fed Half Wave (EFHW)? More bands, shorter length and no dangerous high voltage at antenna feed point from VOLTAGE FED 49:1 TRANSFORMERS!!!
Off Center Fed (OCF) antennas are very convenient as they will allow multiple bands of operation with a simple wire antenna which is fed off center. The Palomar Engineers 8010 OCF is a very popular antenna and consists of an off center fed dipole with sides of 95 feet and 40 feet and it will work all bands from 80-6 meters.
The BULLET-8006 uses the same dimensions but the wire section is 95 feet as in the OCF and the coax outer braid is used for the “other” part of the OCF dipole. We place a choke on the coax at the 40 foot distance from the matching unit and we essentially have an OCF antenna with its great frequency range, but with only a 95 foot wire length instead of the 135 feet required by the regular OCF or EFHW. You feed the antenna from one end which may be more convenient for some installations. This antenna will work on 80-40-30-20-17-15-12-11-10 and 6 meters. Most bands are under 3:1 SWR and easily tuned by your transceiver’s internal antenna tuner or external tuner used with an amplifier.
This antenna is a great stealthy primary or backup antenna and works exceptionally well for apartments, condominiums, homeowner, mobile home parks, RV applications and ARES, RACES, MARS, EMCOMM, NVIS, First Responders and Emergency Preparedness. Compact, Stealthy and Light weight for back packing and portable use.
The antenna is simple to deploy, folds up easily for transport, and with the 95 foot included wire, can work the 80-6 meter bands easily with the built in antenna tuner of most current day transceivers. Some bands may not even require a tuner if the antenna length and counterpoise choke position is adjusted correctly. (see SWR graph in gallery).
These antennas are MUCH BETTER PERFORMERS than End Fed Half Wave antennas using 49:1 transformers that are by their very design frequency limited at the high end. Our end feds work the WARC bands, DO NOT HAVE A DANGEROUS HIGH VOLTAGE at the antenna connection and are shorter to fit in smaller spaces yet provide more band coverage up to 6 meters!
Make the right choice - use and end fed OCF and enjoy the expanded band coverage, additional safety and smaller footprint!
Part #'s:
BULLET-8006-100 for 100 watts PEP/100 watts digital
BULLET-8006-500 for 500 watts PEP/250 watts digital
BULLET-8006-1500 for 1500 watts PEP/750 watts digital
BULLET-8006-5000 for 5000 watts PEP/2.5KW watts digital
The antenna can be used as a up or down sloper, “L” with a vertical section (at either end) and a horizontal section, or as a horizontal antenna between two trees or supports.
Our antenna 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.
For best results we recommend that the coax feed line be at least 50 feet. We also recommend a coax noise filter near radio end of the coax feed line to reduce RFI common mode current from interfering with the radio operation.
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.
Any length of 50 ohm feed line ok (over 50 feet minimum recommended) 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. Position a feed line choke (part# SOFLC) 12 feet from the matching unit.
Use a good quality 50 ohm cable adequate for the power level of your station.The Bullet matching unit is rated for 100, 500 or 1500 watts PEP (depending on model) for SSB and 50% for CW or digital modes. 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: The matching unit output is DC grounded to bleed off static electricity, however it is not RF grounded.
Need a shorter antenna for portable or stealth installation? Check out the BULLET-2006 at 25 feet length and still works 20-6 meters or the BULLET-4006 at 55 FT which works 40-6 meters!
TECH NOTE: If you use LMR-400 or 1/2" coax cable you will need to use a larger diameter ring choke (part# F400-31) so you can get 6-10 turns thru the center to provide enough choking on 40 and 80 meters. If you use RG-8X size cable (which will work up to 1500 watts), then the two included SOFLC with this kit are sufficient if you have 6 turns thru the center of each one in two separate loops as pictured.
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.
SWR TECH NOTE:The SWR graphs shown are specific to the conditions listed including antenna height, configuration (flat top, inverted V, inverted L, etc.) and direction, feed line length and type, geographic location and soil condition, calibration and accuracy of SWR instruments used. Your SWR measurements will probably be different and manufacturer takes no responsibility or liability for these differences beyond the purchase price of the antenna.
Often it is difficult to slip beads on a cable because of a plug or connector. Split beads solve this problem. They come in two halves that fit over the cable. A plastic snap cover holds the two halves together and holds the assembly on the cable.
For RFI use, mix 31 is effective from 1-300 Mhz, mix 43 works from 20-250 Mhz, Mix 61 is for 200-2000 Mhz, and mix 77 favors .1-20 MHz. These frequencies are those of the interfering signal to be eliminated, not the operating frequencies of the equipment to be protected.
Not sure of what sizes you need or solving a RFI problem with devices using multiple size cables? Try the Ferrite Snap On Combo Pack which has sizes from 1/4″ to 3/4″ with either Mix 31 (1-300 MHz) or Mix 61 (200-2000 MHz) or Mix 75 (150 KHz – 10 MHz).
NOW WITH QUANTITY PRICING FOR CLUB , VOLUME PURCHASERS!
Bead dimensions are shown in the picture below and in the table as A, B, C
Ferrite Split Bead Dimensions
Application Notes
Application Note for using these Snap On split beads: How Many Chokes do I need?
You can very effectively increase the choking impedance of smaller cable by using a large hole ferrite bead and wrapping the cable through several times. For particularly difficult common mode current/RFI problems you may need a choking impedance as high as 5-10K ohms. Using multiple beads and multiple turns through each bead will give higher impedances up to a point. At higher frequencies, when the number of turns approaches an electrical wavelength, the choke becomes resonant due to stray capacitance and the inductance of the cable and limits the high end impedance values to less than the above table points.
Some example of ways to wrap cable are shown below.
 FSB-1/4 – 1 turn |
 FSB-1/2 1 turn |
 FSB-1/2 Open Shell |
 FSB-1/2 2 turns |
 FSB-1/2 3 turns |
 FSB-1/2 4 turns |
—–//—–
More examples of split bead use
Ethernet Cable on FSB-1/4
Ethernet Cable on FSB-1/2 – 3 turns for 9X Impedance good filter for 15-30 mhz between 2K-3K ohms choking Z
Three Effective Radio Interference Filters
 FSB-1/4 or FSB-1/2 4 turns for 14-50 Mhz 2K-3K Z |
 FSB-1/2-5 turns for 10-30 Mhz 2K-4.5K choking Z |
 FT240-43 – 14 turns for 3-14 Mhz or use two FT240-43 for 1.8-10 Mhz |
These snap-on chokes are useful for reducing RFI in public address system amplifiers, speaker wires, mic cables, mixer panels, coax cable, telephone wires, computer sound card speakers, dsl/cable connections, remote control heads for ham transceivers (Especially FT-100, FT900, IC-706, IC-7000), AC power cables, DC power cables, home theater cables, video cables, HI Fi cables, guitar amps, linear amp cables, etc.
They are also helpful in suppressing common mode noise/RFI in radio and TV receivers, audio and RF amplifiers. They can also help suppress noise generated by treadmills, exercise equipment, fish tank heaters, oil heater pumps, fluorescent lights, motors, cable modems, DSL modems, computers, and many other electrical devices. Common mode current reduction in computer cables often helps speed up computers.