(click thumbnail)Fig. 1: A copper pigtail for studio grounding
(click thumbnail)Fig. 2: Access for connecting a new pigtail
(click thumbnail)Fig. 3: End the cable mess with AudioSkin.
(click thumbnail)Fig. 4: The slotted plastic sheath ‘zippers’ around the cables to form an organized bundle.Rick Brancadora owns an AM in New Jersey, to which the legend calls WIBG belong. Rick and his engineering consultant, Ted Schober, had been troubleshooting an intermittent VSWR trip that seemed to be coming from their LPB transmitter. The trip would show up on the remote control, but for no apparent consistent reason. One day it was wet, another dry, one day it was warm; you get the picture.
Nothing made sense, so Rick grabbed a broom handle and started rapping on things. When he got to the equipment rack, his rapping found its way to the relay panel for the Sine Systems Remote Control. Bingo; he had a VSWR alarm appear on the remote control.
Further investigation found that the pluggable screw terminal “Euro” or “Phoenix” connector was not fully inserted on the pins of the relay panel. Apparently this intermittent connection was causing the problem; there was nothing wrong with the transmitter.
He solved the problem by removing and re-inserting the plug. Rick says his plugs seem to come loose when mounted horizontally, but would fall off if positioned vertically. Perhaps some strain relief on the cables would hold the connectors in place.
Caig Labs’ Deoxit, a restorative liquid treatment for connectors and contacts, may be another solution. Oxidation building up on push-on connectors can cause all kinds of screwy problems. The Caig product coats the connector pin, cleaning it and minimizing oxidation. Visit www.caig.com.
DeoxIt comes in wipes, liquid pens and sprays. The chemical composition actually improves the electrical connection. This is one product no engineer should be without.
Thanks to Rick Brancadora for reminding us that major problems can be caused by the “little things” — and also that a good whack, now and then, may actually point you to the problem.
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Mike Zeimann is the station manager for WKDN(FM) in Camden, N.J. His tip is a quick formula for converting FM channel numbers to frequencies when you don’t have a cross-reference chart like the one in 73.201 of the FCC Rules and Regulations.
Mike has had this formula sitting in his desk drawer for years and refers to it regularly.
• Subtract 201 from the channel number
• Multiply the result by 0.2
• Add the result to 88.1
For example, let’s say the channel is 263:
263 – 201 = 62
62 x 0.2 = 12.4
12.4 + 88.1 = 100.5 MHz
Mike says while you could do the calculations in your head, he uses a calculator.
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Jeff Twilley, DOE for Delmarva Broadcasting, and his Milford CE Dan Mammone were wrapping up a new studio project recently. From the beginning of the project, they had run 4-inch copper ground strap around the perimeter of the new building that would house the studios. This strap was connected to 10-foot ground rods.
Each studio had a copper pigtail, connected to the perimeter copper strap, and shown in Fig. 1. The console equipment would be connected to this pigtail and centrally grounded.
With the building nearly finished with drywall and paint, imagine their surprise to arrive at the studios to find each pigtail cut off flush with the wall. A little investigating found that one of the contractor’s guys said he understood that he could have all the “scrap” copper when the rooms were finished! With the painting completed, and the rooms “finished,” he lopped off each copper pigtail and sold them for scrap.
Talk about misunderstandings. Also, the engineers never said that. I guess the allure of that precious salvage copper was just too great a temptation.
The contractor agreed to remove the molding and cut the drywall, seen in Fig. 2, so Jeff and Dan could silver solder new copper pigtails. Is copper becoming the new gold? It sure seems that way. Jeff is just glad they didn’t “remove” the perimeter copper strap.
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Fig. 3 is an all too common sight, not only in studios but around desks – even with our entertainment centers at home. AudioSkin to the rescue!
AudioSkin collects cables and zippers them into a wrapped bundle or snake. What makes the product unique is that the plastic bundling sheath has multiple slots through which individual cables can be routed. Just like a zipper pull, a plastic cable clip is used to open and re-close the bundle (to add or remove cables later).
AudioSkin is available in 5-foot lengths, which can interconnect to each other, forming a customized length for your application. In addition to cleaning up computer cabling under desks at the station, this product is ideal for pre-assembling cable runs for remote broadcasts.
An on-line video shows how simple the AudioSkin is to use. It will amaze you. Perhaps the best part is the price; each 5-foot section has a retail price of only $16.99. Head to http://www.audioskin.net.