PA4EME

Dutch Amateur Radio Station

Frank Veldhuijsen

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Versatower BP 60 SX

 

After a long fight with the local government, a BP60SX tower was erected. Hit the picture below and you can download the full strenght and stiffness calculations.

Scroll down to see more pictures made during the build of the BP60SX tower.

An antennatower needs a decent foundation. In this case the foundation is 2x2x2 meters. The wire ends are M24 and welded into a frame and extra iron nets were used to give the whole the needed strenght. The double H-bars the tower is mounted on are not standard. They are custum made to make it possible to tilt the tower over the garage and not into the garden.

The foundation is looking much bigger now. In real the concrete was deposited to the same level as the terrace. So it was easy to fix the terrace again in the way it was.

Our oldest son Sjoerd was very interested in the build. As you can see itís real a heavy duty tilt for the tower. A hand winch was used for the instalation and replaced by an electrical winch, 3-fase pulse controlled.

Grounding the tower. 15 meters of rod were drilled into the ground to reach the needed low earth resistance. A big breaking hammer with a special made adapter was used to do the job.

The first rods were easy and went into the ground easy. But the last two rods were taking a lot of time. On the left you can see that the tower basement is hided into the terrace.

On the internet there are a lot of discussions whether is a good decission to ground an antennatower. Grounding would attrack lightning. Well...in fact only in the very last moment of the lightning the point of discharge becomes in vision of the stroke. In that case it is better to guide the discharge safely to earth so my opinion is to ground a tower always. Be sure that the tower is seperated for the electrical circuits in your house and cables are disconnected.† Coax cables are shielded and this shield should be grounded where the cable leaves the tower. Shielding of seperated cables should be joined at several places to prevent damage. Disconnect the grounding wire in the shack from the main. The earth leakage switch would fail as the tower has a better ground than the small earthing rod that is used. But you are also not allowed to use that rod as lightning safety.