Cushcraft MA6B Six-Band MiniBeam
Parts Inventory: As you unpack, identify and check off each item against the Master
Parts List on the next page. This important step will familiarize you with the various parts
and confirm that you have everything needed to complete construction. If any element
tubes appear to be missing, check inside other larger tubes. Marking each tube as you
inventory—it will speed assembly later, as will sorting the hardware. Save the weight
label attached to the carton. If you claim a missing part, the label has information you'll
need to provide!
Planning: Plan assembly carefully – the work area must be large enough to handle the
10-foot boom and elements up to 18-feet long. Also, the antenna will need to be
supported off the ground when installing the capacitive-hat rods (sawhorses work well).
Trap vents will be exposed the weather during assembly, so cover them if it rains.
Finally, proceed methodically, allow plenty of time, and always have one or more helpers
available to assist with the final installation!
Important Warning: Never attempt to install the MA6B by yourself!
Antenna Location: To realize the best on-air performance, mount the MA6B as high
and in the clear as safety permits -- and remove all vegetation and tree branches from
the area. If you guy the support mast near the antenna, be sure to use Phillystran cord
or an equivalent non-conductor to prevent detuning. Finally, never install where the
antenna could fall and hit power lines, where people or animals could accidentally come
into physical contact with the elements, or where humans could be exposed to highintensity RF-fields. See the ARRL Handbook or FCC website for detailed RF exposure
information and guidelines.
Important Safety Warnings: Never assemble or install this antenna where it could
contact power lines or residential entrance cables -- you could be killed! Also,
when the MA6B is energized with RF, touching the elements could cause painful
injury from RF burns – even at low power levels. Finally, never install where
humans could become chronically exposed to high-intensity RF fields.
Mast: The MA6B mounting bracket accepts masts up to 2 inches in diameter. For safety
reasons, the minimum diameter should be at least 1-1/2 inches with 1/8-inch wall
thickness. If thick-wall tubing is unavailable, use two 1/16-inch-wall tubes telescoped
together. Note that the structure supporting your mast must be able to support the 33pound antenna plus the added weight of your mast and rotor.
Safely Ground: All towers and masts require a safety ground to help protect against
lightning strikes and static build up. Where possible, drive one or more ground rods
directly underneath the antenna and use solid 10-gauge wire secured with non-corrosive
hardware for all connections. Note that the MA6B driven elements are balanced and
have no direct dc path to ground, so installing a coaxial lightning arrestor is also a good
idea. Of course, the best protection of all is to disconnect all feedlines outside of the
building any time the station is not in use or at the first sign of threatening weather!
MA6B Parts List:
[X] Quan Part # Description .
[ ] 2 MT1 21/28 MHz driven element trap assembly
[ ] 4 MT2 24.9 MHz trap assembly
[ ] 2 MT3 21/28 MHz reflector element trap assembly
[ ] 1 80-MN6B-MB Feed network with coax cables
[ ] 2 MA5BEF Element Tube, 1-1/8" OD x 84", slotted both ends
[ ] 2 MA5BEE Element Tube, 7/8" OD x 12", slotted one end
[ ] 2 MA5BED Element Tube, 1-1/8" OD x 46", slotted one end, drilled other end
[ ] 4 MA5BEC Element Tube, 7/8" OD x 7" slotted one end, drilled other end
[ ] 2 MA5BEJ Element Tube, 7/8” OD x 13-1/2 slotted one end, drilled other end
[ ] 6 MA5BEB Element Tube, 1" OD > 7/8" OD (swaged) x 36", slotted one end
[ ] 2 MA5BEA Element Tube, 1-1/8" OD x 34", slotted one end, drilled other end
[ ] 2 MA5BEG Element Tube, 1" OD > 7/8" OD, (swaged) x 41-1/2", slotted one end
[ ] 2 20-MA6B-DD Element Tube, 7/16" OD x 48", drilled one end, slotted other end
[ ] 2 20-MA6B-DE Element Tube, 3/8" OD x 9"
[ ] 1 20-MA6B-EG Element Tube, 7/16” OD x 72", slotted both ends, drilled at center
[ ] 2 20-MA6B-EH Element Tube, 3/8" OD x 28"
[ ] 2 20-MA6B-BC Boom Tube, 1-1/2" OD x 48", slotted one end
[ ] 1 20-MA6B-BD Boom Tube, 1-1/2" OD x 21", slotted both ends
[ ] 1 20-MA6B-BE Boom Tube Insert, 1-3/8" OD x 48"
[ ] 2 735-1106 Element Mounting Bracket, 6M driven element
[ ] 2 205560-1 Insulating plate, 6M driven element
[ ] 2 193-853 90-degree mounting bracket for insulating plate
[ ] 1 738-1213 Reflector insulating plate, ¼” x 2-1/2” x 3-1/2”
[ ] 1 735-1109 “L”-mounting bracket for reflector insulating plate
[ ] 16 HXR41 41" X-hat rod
[ ] 8 HXR26 26" X-hat rod
[ ] 2 HXR24 24" X-hat rod
[ ] 1 240116 Silicone grease packet
[ ] 1 050115 UHF connector boot, black
[ ] 28 190028 X-hat Half-washer
[ ] 26 190026 X-hat Element bracket
[ ] 4 190033 U-Bolt Backing plate for elements
[ ] 4 190143 Element-to-Boom clamp
[ ] 4 190033 U-bolt backing plate
[ ] 1 758-9200 1/4”-20 x 2-3/4” U-bolt assembly
[ ] 4 010402 1/4"-20 x 1-1/2" ID x 3-3/4" U-bolt
[ ] 10 010085 1/4-20 Hex nut
[ ] 10 010084 1/4" Split lock washer
[ ] 1 190070 Boom-to-Mast clamping plate
[ ] 2 010403 5/16-18 x 1-5/8" x 3" U-bolt
[ ] 2 010404 5/16-18 x 2-1/8" x 3-1/4" U-bolt
[ ] 8 010119 5/16 split lock washer
[ ] 8 010118 5/16-18 Hex nut
[ ] 2 122096 Fiberglass driven-element insulator, 1" OD x 10"
[ ] 1 030413 Worm clamp, 1-1/2 to 1-3/4"
[ ] 4 030412 Worm clamp, 1-1/4" to 1-1/2"
[ ] 8 030411 Worm clamp, 1" to 1-1/4"
[ ] 16 030410 Worm clamp, 7/8" to 1"
[ ] 4 030407 Worm clamp, 3/8 to 1/2”
[ ] 2 050046 1-1/2" Plastic end cap, for boom
[ ] 8 050061 7/8" Plastic end cap for HF elements
[ ] 4 050251 3/8" Plastic end cap for 6M elements
[ ] 46 010941 #8 Lock washer
[ ] 46 010011 8-32 Nut
[ ] 6 010079 1/2" x 8-32 Screw
[ ] 4 010072 3/4” x 8-32 Screw
[ ] 2 010229 1" x 8-32 Screw
[ ] 2 010040 1-1/8” x 8-32 Screw
[ ] 16 010120 8-32 x 2" Screw
[ ] 14 010231 8-32 x 1-3/4" Screw
Step-1. Assemble the boom using the parts listed below:
[ ] 2 Boom Tube, 1-1/2" OD x 48", slotted one end (20-MA6B-BC)
[ ] 1 Boom Tube, 1-1/2" OD x 21", slotted both ends (20-MA6B-BD)
[ ] 1 Boom Tube Insert, 1-3/8" OD x 48" (20-MA6B-BE)
[ ] 4 Worm clamp, 1-1/4" to 1-1/2"
[ ] 1 Boom-to-Mast clamping plate
[ ] 2 5/16-18 x 1-5/8" x 3" U-bolt
[ ] 4 5/16" split lock washer
[ ] 4 5/16-18 Hex nut
[ ] 2 1-1/2" Plastic end cap, for boom
Boom Assembly Stages
Boom Assembly
1-3/8" x 48"
1-1/2" Worm Clamp (4)
Step-1
1-1/2" x 21"
Step-2
Step-3
Boom-to-Mast Clamp Assembly
End cap
13-1/2"
60"
Driven Element End
End cap
1-1/2"OD x 48" 1-1/2"OD x 48"1-1/2" x 21"
1-3/8" x 48"
13-1/2"
57"
Reflector End
Installation Notes: Assemble boom tubes as shown above. Install end caps and secure
all worm clamps tightly to prevent the boom sections from rotating out of alignment when
elements are attached. Before installing the mast-to-boom clamp, measure off and mark
the boom at 57" (see below):
Top View, Mast-to-Boom Plate Installation
5/16" x 18 Nut (4)
57" mark
5/16" Lockwasher (4)
Boom-to-Mast Plate (1)
Boom
3" U-Bolt (2)
Step-2. Assemble the 20/15/10-Meter Driven Element using parts listed below:
[ ] 2 Element Tube, 1-1/8" OD x 34", slot one end, drilled other end (MA5BEA)
[ ] 2 Element Tube, 1" swaged to 7/8" x 36", slotted one end (MA5BEB)
[ ] 2 Element Tube, 7/8" OD x 7" slotted one end, drilled other end (MA5BEC)
[ ] 2 Trap, 21/28 MHz driven element, MT1
[ ] 1 Driven-element insulator, fiberglass, 1" OD x 10"
[ ] 4 Worm clamp, 7/8" to 1"
[ ] 2 Worm clamp, 1" to 1-1/4"
[ ] 2 8-32 x 1-3/4" Screw
[ ] 2 #8 Lock washer
[ ] 2 8-32 Nut
[ ] 2 7/8" Plastic end cap
20/15/10 Driven Element Assembly
End Cap
7/8"-1" worm clamp
EC EC
<
MT1
1" to 1-1/4"
Worm Clamp
EB
(Insert 4") (Insert 4")
Insulator
EA
8-32 x 1-3/4" screw (2)
EA
1" to 1-1/4"
Worm Clamp
7/8"-1" worm clamp (2)
EB
>
MT1
End Cap
8-32 Hex Nut
#8 Lockwasher
Insulator
1-3/4" 8-32 Screw
Installation Notes: Insert the insulator attachment screws in same direction and tighten
securely (these screws will become the connection points for the feedline). Insert EB
tubes 4 inches into EA tubes. Install all traps with the arrow pointing away from the
boom. Install end caps on EC tubes.
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