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Spread That Paperwork Around

Multi-rack documentation simplifies troubleshooting

Fig. 1: Documentation drawings are placed above each rack. Shaun Sandoval is market chief for the new Cumulus San Francisco cluster. He was responsible — along with associates like Senior Vice President of Engineering and IT Gary Kline, Vice President Engineering Martin Stabbert and Project Leader Michael Gay — for new radio studios built in downtown San Fran.

Touring the facility, one can’t help but notice the documentation, prepared by Michael Gay. In addition to providing Visio-brand drawings of all the rack equipment, he collated drawings by rack and placed them on the top of each rack with a magnetic clip, seen in Fig 1. The rear of each rack has a duplicate set of drawings and relevant IP addresses, as shown in Fig. 2.

Documentation of equipment and wiring is important, but especially when you have multiple studios. The engineers placed an overall documentation package in the rack room, but by splitting the docs up and assigning bite-size drawings to each rack, they’ve made service and assessment easier.

Fig. 2: Duplicate docs are mounted at the rear.

Frank and Dave Hertel, engineers with Newman-Kees RF Measurements, recently built a low-power FM station for a friend who has owned several full-power stations and sold them. The friend couldn’t get radio out of his blood, hence the LPFM buildout.

To make the LPFM official, he decided he needed a flashing light atop the 30-foot tower at his house. Frank used an LM-555 timer to drive four super bright LEDs. The total current draw is about 90 mA, so a wall-wart AC to DC transformer will power the circuit. There’s nothing fancy about the schematic, see Fig. 3. It can be easily mounted inside an old tower side lamp fixture, to add realism, seen in Fig. 4.

Fig. 3: The flasher circuit schematic is built around the LM555 timer.

Fig. 5 shows the chrome LED-mounting pipe, a scrap piece of sink drainpipe. The LEDs are glued into holes drilled in the pipe. To mount the pipe, Frank cut two slots about a half-inch apart. Bend the flanges, formed by these slots, 90 degrees. That forms mounting flanges that can be affixed to the side-light socket.

Fig. 4: Mount the flasher in an old tower side-lamp fixture. Fig. 5: The LEDs are mounted to a piece of chrome sink drainpipe.

The tower side-light fixture is small enough that it can be mounted on a block of wood and used as an “engineer out of office” desk flasher. The circuit can also be pressed into service to signal an EAS alert, hotline ringing or after-hours doorbell in the studio.

Keep in mind that this is a novelty circuit and should not be used as an Federal Aviation Administration-approved tower light flasher.

Fig. 6: Use a floor mic stand to hold a soldering iron inside a rack. Mark Voris, technical director for Spirit Catholic Radio, always comes up with a great tip or two. Fig. 6 is no exception.

Some engineering tasks require a third hand; soldering certainly falls into that category. It can be a chore to juggle solder, the iron and the wires or connector. If you’ve seen my NAB Show or SBE Workbench presentations, you know a spring clipboard can come in handy. The spring clip holds the connector to be soldered and frees your hands to manipulate the solder and iron. But what if you have to solder wires or resistors to a terminal strip in a rack? Fig. 6 provides the answer.

I wonder if soldering iron manufacturer Weller knew the diameter of its soldering irons was the ideal dimension to fit into a standard mic stand?

Desk stands will work too, but the beauty of the floor stand is that the iron can be positioned in the upper portions of an equipment rack.

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Author John Bisset has spent 45 years in the broadcasting industry and is still learning. He handles West Coast sales for the Telos Alliance. He is SBE Certified and is a past recipient of the SBE’s Educator of the Year Award.