Inspect Trouble Spots With a Scope

Also, shine some light on your rack room
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Here’s a multipurpose troubleshooting tip from Los Alamos Neutron Science Center RF Systems Engineer John T. M. Lyles. It’s a fiber-optic bore scope inspection tool with video.

John has used it to inspect the inside of large cavity amplifiers and to look down the annulus of 6- and 9-inch coax, searching for burned contacts and arc marks. Now you don’t need to tear down a system just to inspect it. You can also look down dry drainpipes for obstructions or dropped tools.

Have you ever lost a screw around an engine and wondered where it landed? Then the bore scope is for you.

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Fig. 1: A florescent light fixture illuminates equipment racks. John writes that many sources sell these, such as Harbor Freight (www.harborfreight.com). Cheap ones don’t have the best resolution or features; don’t expect bottom-end models to provide superior performance. John picked up a brand by Starrett for $200 and reports that it is fine for quick and simple uses.

He writes that the shorter bore scope is better than the longer ones; the latter become difficult to maneuver.

Look for a scope that has variable brightness LED illumination, a right-angle lens and the ability to articulate the far end of the fiber with a joystick.

John also was fortunate to convince his management to get an expensive Olympus brand, which has a large LCD remote screen and the ability to save snapshots to a USB stick. The Olympus has a fully articulated end that can see in every direction. It extends to 6 feet; the diameter of the camera end is 0.35 inches. The Olympus has removable wide-angle and long lenses, including a right-angle illuminated lens.

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Adequate rack lighting is a recurring problem. Fig. 1 shows a creative way to shine some light on the subject.

Spirit Catholic Radio’s Mark Voris sent in this suggestion. Depending on the size of the lighting fixture, several racks can be illuminated with one fixture. The protective metal and plastic shroud protects the florescent bulb compared to open fixtures.

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Fig. 2: With spring approaching, check all conduit openings and seal holes with expanding foam.

Spring is right around the corner, and where cold is receding it won’t be long until nesting insects and rodents look for new homes.

Fig. 2 shows another of Mark’s solutions, a satellite conduit plug. Check all conduits leading into buildings. Use an end cap or expandable foam, as shown, to discourage these varmints.

When you run conduit into the building, don’t forget a pull string for future wiring pulls. Look closely and you’ll see Mark’s got one.

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It’s not always possible to mount short tower sections on the roof. The next best thing is close to the side of a building. In Nebraska, WJAG(AM) Chief Engineer Jerry Jaroska was tasked to install a tower against his studio building but the only available side of the building was next to a driveway.

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Fig. 3: Concrete pylons protect a small tower from vehicle traffic. Fig. 3 shows protective concrete pillars that were installed on either side of the tower, shielding it from errant car bumpers.

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Our photo of the mid-’60s radio studio in the Feb. 1 Workbench has generated a lot of comments, although none as thorough as one from Marlin Taylor. Based on the cart machines and especially the poster, sleuth Marlin reaches the following conclusions:

First, this station likely played country music and maybe some gospel, given that the poster is about a southern gospel music concert.

Next, the station is probably in New Albany, Tupelo or Boonville, Miss., based on the town listed on the poster; these places had stations licensed within that range.

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The year is likely 1967, with the prime clue being “Saturday October 7th” on the poster. The next earlier year would have been 1961, but this is not as likely; cart machines were still quite new then. Plus, the Dixie Echoes were listed second on the list of artists appearing, and they were just organized in later 1960.

Of course, it could have been 1972, the next year when Oct. 7 was on a Saturday, but Marlin doesn’t think the picture is any later. A good number of small-market stations were still using carts and records in the ’70s, so who knows?

Contribute to Workbench. You’ll help your fellow engineers, and qualify for SBE recertification credit. Send Workbench tips to johnpbisset@gmail.com. Fax to (603) 472-4944.

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.

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