It's Tuesday and week 4 in my series about the building of one of the new radio sites for the County of Riverside's public safety radio system. As you can see one week can change a whole lot of things. Concrete was poured over reinforcing bar (rebar) in the 12ft deep holes for the tower foundations. A couple of days later the 100ft tower was constructed by tower climbers who bolted the 20ft sections together with the help of a crane. Then later that same day the prefabricated building was brought in by truck from Arizona. A crane lifted the building onto it's foundation pad, which it was then bolted to. Out of view in this photograph the propane gas tank, which is used for emergency back up generators has been set and bolted onto it's concrete pad.
Now one of the most important parts of a radio site gets installed and the trench you see here is part of that. That work is GROUNDING (or earthing to the Brit's reading this). Because radio towers sit high up in the air above everything else and are made from steel they have a habit of being struck by lightening. I never had any idea about the amount of time, effort and engineering that goes into the grounding system to deal with lightening strikes. Without an effective grounding system one lightening strike could destroy every piece of equipment inside the radio site. A lightening strike is so powerful it can take many different routes into the equipment building and the grounding system has to deal with every one of those possible routes to dissipate the electrical charge effectively. Click on the photograph for a larger version.