AM Ground Systems Company

WIBC

Indianapolis, IN

WIBC is an Emmis Communications owned 50kw heritage station.  WIBC's ground system employs a rather odd design that where an elevated CopperWeld counterpoise extends from the tower base out to where the counterpoise radials were Cadwelded to the top rail of the chain link fence.  The radials were then cadwelded to the bottom rail of the fence structure and continued underground.  The fence structure was originally all welded but has deteriorated over the years such that several of the bottom rails had broken free from the rest of the fence structure.  When the radials derailed(?), a substantial portion of the ground system was left loosely connected via a RF drain wire bonded to the rails, posts and fence fabric.

 

 











The counterpoise radials are bonded to a heavy copper/brass ring mounted on a steel framework. The ring and framework are spaced away from the tower by several inches. The radials were stretched and bonded to the top fence rail visible at the top of this picture.












Although most of the engineering documentation for the original construction is still on-site, there is no mention of the thoughts behind this unusual arrangement.






The normal ground radials were CadWelded to the bottom rail and continued on below ground as normal.






There was only a single 2in strap running from the tower base and ring out to the bottom rail. On several of the towers, the rail welding was broken and the only connection was thru a #8 RF drain wire running around the fence fabric. A new perimeter strap was installed around the existing fence and eight new sections of strap were installed from the building out to the fence perimeter.












We carefully excavated around the fence perimeter and installed a 4in strap under the radials.












A single block was removed from the back wall of the ATU building and 3ea 4in straps connected from the new infrastructure to the ATU ground.
























Anton (left) and Carl (right) doing the serious work. These guys worked hard and allowed Steve and I to concentrate on the grounding work.






Anton






Carl






The copper ring.


















WIBC Transmitter building and STL tower.






Big Bird.












This hawk guards the site grounds. The site has a full perimeter fence and alarm system. Having an attack hawk is a nice touch.









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