I have wanted for a little while a heavy duty drive on mast base that could take the stresses of a large mast plus a large vertical antenna (or antennas) bolted to the top.

I ordered up a section of 50mm box section and 40mm angle iron, both 1m long and 3mm thick, all over engineered.  I cut the angle iron into two 500mm lengths, and the box into two 250mm lengths and a single 500mm length.

Taking the two 500mm angle iron lengths and the two 250mm lengths, I arranged them into a square, and tacked them into place with the MIG welder.  The internal measurements of the “square” needs to have between 225mm and 240mm between the angle iron sides for the wheel to be able to drive on and the weight of vehicle hold the base in position.  My car (and van) needed 235mm.  This fits very nicely with the 250mm box section sides.  In double checking they were square and of the correct gap, I then welded them properly on both the top and bottom.

This left a single length of 500mm box section left over.  This is to form the vertical receiver that the mast will slot into.  This was then tack welded into position and checked that it was indeed 90 degree perpendicular to the “base square”.  Then the joints were welded properly.

Lastly a small hole was drilled by my bench pillar drill in order to allow any rain water that may run down the mast to escape.

The whole fabrication took a couple of hours, and spray painted in black Smoothrite paint.

To allow for unlevel ground, and to allow the mast to remain vertical, a test was set up on slightly sloping ground, and a simple solution of a screwdriver wedge allows some adjustment.

Interestingly, the base actually is sufficient to act as a wheel chock to my estate car.  In testing, the car handbrake was released and the base held the car in position on this slight slope.

Here I have repurposed a child’s swing’s green legs to make a 40mm “sectional pipe” mast of 2mm walls.  This extends about 3.75m above the car in 1m sectional lengths (the top section being shorter).  Now to decide what antenna to fit to the top.  I am thinking of one of those 80m to 6m multi band verticals that can be assembled in sections to go with this sectional portable mast.