Barrett 912 Series User manual

BARRETT 912 Multiwire broadbands can be mounted either in a horizontal or inverted 'V'
configuration. The minimum distance between the masts is 32 metres for the 27 metres mast and
60 metres for the 54 metres mast. The recommended mast height is 15 metres. The balun hangs
below the antenna.
In the horizontal configuration the major radiation direction is broadside to the antenna.
BCM91203/4
BARRETT
912 Multiwire broadband dipole antenna - 1Kw (54M/27M)
P/N BC91203/BC91207

In the inverted 'V' configuration, the recommended mast height is 15 metres and at this height
the 2 metre stub masts are each installed at a minimum of 9 metres from the mast base. In this
configuration the mast must have an offset or out-rigger bracket, at least 0.8 metres long, to
hold the antenna away from the mast. Install the antenna as illustrated in the diagrams, in the
inverted 'V' configuration the eye on the top of the balun is used to attach the support halyard.
In the inverted 'V' configuration the antenna becomes more suitable for NVIS, with radiation
being directed at high angles, but omnidirectional around the antenna horizontally
BARRETT
912 Multiwire broadband dipole antenna - 1Kw (54M/27M)
P/N BC91203/BC91207
BCM91203/4

Support towers may be either lattice masts as illustrated, tubular telomasts or other support
structures that may be available locally. It is recommended that the halyards used to support
the antenna be either UV stabilised dacron chord or wire rope and that pulleys should be of
stainless steel construction
As with all antenna installations ensure the antenna is as far from sources of electrical
interference as possible and in a position that makes it impossible for the antenna to come in
contact with high voltage overhead mains wiring.
912 Multi Wire ANTENNA
UNPACKING INSTRUCTIONS
Note: Do not unroll antenna wires until the antenna is onsite in a large area
1. Remove the antenna from the box so that the load resistor hangs downwards below the
antenna.
2. Spread the antenna on the ground as shown below
3. Remove all masking tape.
4. Starting at the ends, gently with wire cutters or scissors, remove the cable ties from the first
set of three coils of wire. Extend this antenna section as far as possible. Move onto the inner
rolls and repeat.
When all cable ties have been removed, the wires must be extended to full length to
prevent them becoming tangled.
If twisting or crossing of the wire occurs during unpacking don't panic and reach for the wire
cutters. Instead try to trace the crossed or twisted wire and correct the problem.
BARRETT
912 Multiwire broadband dipole antenna - 1Kw (54M/27M)
P/N BC91203/BC91207
BCM91203/4

HORIZONTAL CONFIGURATION
Installation Instruction
1. Unpack the antenna (see unpacking instructions) and lay it out on the ground between two
mounting poles with the load element and balun wires below the antenna wires. (as shown
in picture below)
2. Attach rope to each insulator (one at each end) and slowly hoist between the two mounting
points (tower/poles even a tree or to the roof) ensuring the wires do not tangle. Raise to
about eye level.
3. Balun (black box) connection: Once the antenna has been raised to a convenient height,
attach the balun and coax cable as shown below. All stainless steel nuts and washers
required are provided with the balun. RG 213 coax cable strain relief is provided, where
appropriate, by a pigtail strain reliever (PTS) attached to the rear of the balun.
4. Raise the antenna to the desired height and secure ropes. A slight curve in the antenna is
normal.
Load Group
Load Terminal
Load Group
BARRETT
912 Multiwire broadband dipole antenna - 1Kw (54M/27M)
P/N BC91203/BC91207
BCM91203/4

Suspension Point
Load Group
Load Terminal
INVERTED “V” CONFIGURATION
Installation instructions
1. Unpack the antenna and lay on the ground making sure the wires do not tangle, with the
balun wires above the antenna wires. i.e. upside down. (as shown in the picture.)
2. Remove the load elements by removing the stainless steel hanger brackets from the
fibreglass spreader rods.
3. Re-fit the loads in the same way, but now under the antenna wires.
4. Re-tighten setscrews.
5. Fit the balun fitted with the yoke as shown in the picture
6. Attach hoisting cord to the suspension yoke. Slowly raise ensuring that the wires do not
tangle
7. When at a convenient working height, connect the coax to the plug at the base of the balun
(black box). Fit the coax to the pigtail strain relief. Raise the antenna to full height.
8. The ends of the antenna now need to be secured. Attach cord to the insulator at each end of
the antenna. Tie these cords to convenient points to secure the antenna in position. These
should ideally be tied at a height, or in a safe area, to avert possible contact and risks of
minor shocks or burns.
BARRETT
912 Multiwire broadband dipole antenna - 1Kw (54M/27M)
P/N BC91203/BC91207
BCM91203/4