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Wall-mounted Mast
This mast was erected in January 2024 to support two home
made VHF antennas and a Yaesu antenna rotator on the end wall of my
garage/workshop. At that time, my VHF antennas were a J Pole
vertical antenna, and a 7 element horizontally-polarised Yagi,
both for the 2m band. In practice, the 144 MHz J Pole was found to
provide good service on 70cm also.
For an aerial view of the current installation, click here.
Work commenced by identifying the best location by considering the existing features and uses of the south-facing wall of the workshop. The workshop is a separate part of the garage which doubles as the radio room. The first job was to use a short length of aluminium scaffold pole to align the T and K brackets in the chosen spot, to the right of an existing outside tap and associated wash-stand. The upper 'K' bracket was mounted using stainless steel bolts that passed fully though the single-skin cement block wall and rendering. Curiously, perhaps, the cement block wall is double-skin up to ceiling height, and then single skin up to the roof. The lower 'T' bracket was fitted using substantial screws into equally substantial nylon wall plugs. The supporting pole rests on a base so that most of the mass of the structure is supported by base, hence reducing the forces on the brackets. By having a swivel at the base, the mast can be raised and lowered with the aid of a pulley anchored to the K bracket. The next photo shows the K and T brackets mounted in position, and the area being prepared for installing the base.
The photo below shows where the base needs to be centred. The base is made by digging a small hole in which to place the high density cement block shown in the photo.
Once the hole had been dug, the bottom of the hole was compacted by tamping the surface with the aid of the concrete block.
The bottom of the hole was then levelled with a little washed concreting sand.
The concrete block was then set down in the hole, and the the hole back-filled to create a level surface.
The next photo shows a small concrete paving slab that has been placed centrally on the concrete block, using the base of the pole to check that the paving slap was aligned correctly. Four pilot holes were drilled through the paving slab and into the concrete block with the aim of fixing the paving slab to the concrete block.
The paving slab was then removed, and the four holes enlarged in the concrete block to fit wall plugs. The pilot holes in the paving slab were then enlarged to a clearance size to allow screws to pass through the slab into the concrete block.
The paving slab was then fitted to the concrete block using stainless steel screws and washers.
Finally, mounting holes for the swivel were drilled down though the paving slab and into the concrete block below. Large plastic wall plugs were then used to mount the swivel to the base assembly. The component used as a swivel is not intended for this purpose, and it will not allow the pole to drop below about 14 degrees. So it is important that support for the mast is provided so that the swivel doesn't bottom out. If you don't like this arrangement, proper swivel bases are available, but at greater cost.
Raising and Lowering the Mast
To see a video of the mast being lowered in March 2025,
click here.
The following photographs show the general arrangement.
Cabling To provide a maintenance point, a waterproof wall-mounted enclosure was mounted on the outside of the wall to protect the connections for the rotator and for the feeder cables to the three antennas. The enclosure is a Hylec ABS 'Debox' measuring 350 x 250 x 150 mm, Part Number DED002, which I purchased from CPC.
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