|
WOLFRADIO.COM
CB Antenna
Wolf Bay 11m
The
Wolf Bay 11m is a half wave center mounted dipole for the 11-meter (CB)
band. It is center feed with a gamma match and is tunable from 25 to 30
MHz. (also available for other bands) It can be mounted for vertical or
horizontal polarization on a tower or pole or any other suitable structure.
Its all aluminum DC grounded design makes it ideal for the high lightning
and static areas of the south. This antenna will not attract lightning
like the common fiberglass antenna and can withstand a substantial discharge
with minimal or no damage. (Wolf Antennas come with Lightning Warrantee)
It has become popular with tower crane operators because of its ease of
mounting, lightning resistance and greater range. When replacing a Antron
with a Wolf Bay 11m on a tower crane a minimum of 3 to 5 dB gain is realized
in almost every direction. (See
polar plots 2,3) The length is close to 18 ft. over all and the mounting
boom is 3 ft. long 1-1/2 inch diameter thick wall pipe. Stock power handling
is 1kw and high power version is 5 kw. This antenna is considered to be
omnidirectional but its pattern is offset a little in the direction away
from the support structure. (See polar plots 1,4) The theoretical gain
of a half wave dipole is only 2.1 dBi but the improvement seen by switching
from a fiberglass antenna to this type is dramatic.
polar
plot 1 polar plot
2

In this test the antennas are 260 feet high on a tower
crane and no ground radials are used. The arrow points in the direction
of the crane boom. In the first plot my antenna is mounted in a lower position
on the railing behind the control cab and closer to interfering metal. But
even in this position there are no dead zones in the pattern, its only offset
by 3 to 4 dB. In the second plot the Antron is mounted in the advantage
position higher than the Wolf bay on the top railing of the counter bridge.
The Antron's pattern (dark shading) is distorted and has a greater than
-20 dB dead spot in it. The red shaded area shows the Wolf Bays improvement
in coverage. It not only filled the dead spot but also has better gain in
275 degrees of the circle. Moving it to the higher spot provided superior
coverage in all 360 degrees (Plot 3). Plot 4 shows the coverage of a single
Wolf Bay when mounted on a Rohn tower the pattern is offset by 3 to 4 dB
in the direction away from the tower.
polar
plot 3 polar
plot 4

Two or more Wolf Bay 11m's can be phased together
to give higher gain and pattern shaping. If 2 bays are mounted side by
side 9 feet apart or more and fed in phase a bi-directional figure eight
pattern results. Two bays stacked one over the other and spaced at least
3/4 wave produces a high gain omni. This is the configuration I am currently
using with great success.
The
theoretical gain improvement is only 3 dB but vertical spacing (3/4 wave
or more) dramatically increases the effective aperture. This, because
it prevents individual aperture overlap results in signal increases way
better than 3 dB. In fact on the back side I see only 3 dB, but on the
coverage side 5 to 6 dB is typical.
Mounting bracket

Gamma, slider and coax connector bracket
Price $90.00
Wolf Bay_11m mounted on tower crane

SPECS:
Wolf Bay_11m
CONSTRUCTION ----------- ALL ALLUMINUM
STYLE ------------------------------ tower leg mount
POLARITY -------------- (single) VERT. or HOR.
LENGTH -------------------- 18 FEET (1/2 WAVE)
GAIN ------------------------------------- 2.1 DBI MIN.
POWER RATING ---------- 1000 WATTS ICAS
FREQUENCY ---------------(tunable) 25 - 30 Mhz
S.W.R. ---------------------------------------- 1.1 to 1.0
FEED ----------- D.C. Grounded, Gamma Matched
For
questions, comments, antenna orders,
etc. send email: EddieC@wolfradio.com
|