Custom mounting adapter for 40 MM Square Boom

The 40 MM square boom adapter is suitable for OptiBeam antennas such as the OB 9-5.  The adapter consists of a 2.5 inch aluminum tube that fits over the boom.

Status - 17-Oct-2009  Bill / KM1C will be beta testing the 40MM adapter kit along the 80MM adapter and two of the stackable TiltPlates.   His project pictures will be posted here when complete later this year.

Note: although the head of the bolt is at the top, it will actually be on the side of the boom facing down toward the ground.  See pictures below.

Short Boom sample shown drilled for one of the holes.   Slide the adapter over the boom with the larger hole facing down.  The larger hole goes on the side of the boom facing down (toward the ground).  Mark the boom and drill the 4 holes in the boom with a 7/16 drill. 

Tape the thick SS washer to the boom before sliding the adapter over the boom.  The washer goes on the bottom side (facing the ground).

Insert the bolt through the larger 5/8 inch hole.  Tighten the nylon insert lock nut snugly

Adapter in place.  Note: the larger hole and screw head is down to allow maximum clearance to the other parts of the antenna. 

Bill / KM1C ordered the 40MM adapter for his "stackable" TiltPlate with the optional KARLock.  The KARLock latch mounts to the visible tube.  The mast attaches to the backside of the fixed plate.

Another angle

End view showing the square boom in the 2.5 inch tube and one of the adapter bolts is visible.