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 4010 OCF is a very popular antenna and
consists of an off center fed dipole with sides of 55 feet and 11 feet and
it will work all bands from 40-6 meters.The BULLET-4006 uses the same
dimensions but the wire section is 55 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 12 foot distance from the matching unit and we
essentially have an OCF antenna with its great frequency range, but with
only a 55 foot wire length instead of the 66 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
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 55 foot included wire, can work the 40-6 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 (EFWH) antennas
because they work the WARC bands, do not have a dangerously 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 Numbers:
- BULLET-4006-100 for 100 watts PEP/100 watts digital
- BULLET-4006-500 for 500 watts PEP/350 watts digital
- BULLET-4006-1500 for 1500 watts PEP/1000 watts digital
- BULLET-4006-5000 for 5000 watts PEP/2000 watts digital (note: CU-4-5000 supplied - weight is 3 pounds for 5KW and box dimensions 4 x 4 x 2 inches
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. Zig-zag and 90 degree bends
horizontal are also ok.
BULLET Matching Unit
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 25 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 25 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 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!
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.
LMR-400/RG213/RG8 (1/2" coax users): Use 3 turns thru included choke which
should be enough choking for 40-6 meters. If you find you need more
choking, use a second SOFLC with an additional 3 turns in series with the
first choke as shown in the pictures.