(click thumbnail)Fig. 1: Using Austin Ring Transformers? Braided wire straps should be connected to a solid ground point.Sometimes you’re the windshield, sometimes you’re the bug. Good planning can make the difference.
Engineers who have experience with Austin Ring Lighting Transformers are scarce. However, the picture in the July 4 Workbench caught the eye of one, P.E. Ralph Winquist of Lake Worth, Fla.
He writes that the installation of the transformer in the first photo of that column is incorrect. When the transformer is placed with the secondary winding directly above the primary winding, the recipe can be disaster.
In a good rainstorm, water will run off the secondary and onto the primary. This will short out the base insulator, and the station will go off the air.
Instructions from Austin recommend that the secondary winding come off the tower at a 45-degree angle, and encircle in the center, the primary winding coming up at a 45-degree angle. The two windings would then project outward at a 45-degree angle.
When placed in this manner, water from a heavy rain would drop free to the ground, and not short out the base insulator. Proper placement can be achieved using 1-inch pipe nipples and two 45-degree elbows. A kit is available from Austin.
If your towers use Austin Ring Transformers, also inspect the grounding braids, shown here in Figure 1. These are braided wire straps that should be connected to a solid ground point.
. . .
(click thumbnail)Fig. 2: Bring along a strong trouble light to inspect components inside dark equipment cabinets.
It’s dark inside the back of many transmitters – a good reason to use a strong trouble light to inspect components. Figure 2 shows two capacitors. The rear-most capacitor is leaking oil.
Note the black stain around the right terminal. In this case, it’s PCB oil. The spillage is symptomatic of a pending failure, and should be replaced. The PCB oil issue should raise a red flag. Do not become contaminated with it.
Similar problems such as cuts in high-voltage wire or burned connections need to be sought out during a scheduled maintenance period. Make a list of suspicious parts or components, order the spares and get them replaced.
Where a transmitter has a history of burning HV wire, order a coil of this wire from the transmitter manufacturer. Ignition wire from an auto supply store can get you over the hump in some cases, but nothing beats having the factory replacement on the shelf.
. . .
With a season of remotes under your belt and fall sporting events right around the corner, you’re probably tired of lugging all that remote gear. Take a look at the offerings from Remin’s Kart-A-Bag at www.kart-a-bag.com.
This company sells a variety of fold-up luggage carts – you know, the kind you see everyone use at the airport. The problem with the airport models is they are not designed for weight in mind. Kart-A-Bag’s line handles weights of 100 to 300 pounds, and includes a tri-wheel model to handle really heavy loads.
If you really go all-out for remotes, take a look at the HD-500. This model will carry 600 pounds in either an upright hand truck or flat-bed mode. There’s also a shelf option, so the truck can be used to provide shelf workspace, once the gear has been delivered.
A brochure describing the line can be obtained by contacting Kart-A-Bag, which is a division of Remin, Joliet, Ill. Telephone (800) 423-9328. Thanks to Ed Bukont of Comm-Struction, a division of TESSCO, for passing on this handy information.
. . .
A few issues back, Radio World ran a review about the Neutrik Minirator and Minilyzer. A tip to keep these portable test instruments in your toolbox followed in the Workbench column.
Everyone I’ve talked to loves these instruments. This includes WRQX/WJZW(FM) Chief Engineer Dave Sproul in Washington, who writes that he loves his Minirator, and has a Minilyzer budgeted.
However, Dave also sends a word of caution. Because the parameters of the Minirator are set in software, a static “crack” or RF can sometimes change the settings at an inconvenient time. Dave was feeding mic-level tones to the sound system of a church recently, when something clicked the output level of the Minirator from -50 to +4.
He’s only grateful that the speakers didn’t explode from their mounts! The problem isn’t an every day occurrence, but is can happen. Beware.
. . .
(click thumbnail)Fig. 3: Plan now for that visiting TV crew or live band in your air studio.
When you’re planning to build a new studio, keep in mind that extra microphones or a feed for the TV news camera might come in handy.
If you’re morning show hosts live bands, you may need a number of ins-and-outs, but no place to put them. Fig. 3 shows the chassis of an audio snake, with holes for the XLR connectors already drilled.
You can either buy a pre-wired snake, or cannibalize one as shown here. Include both mic- and line-level feeds for the TV news crew, headphone feeds, mic- and line-level inputs (for the band gear), and plenty of AC outlets.
If you can, add a couple of AC outlets up near the ceiling behind the console. Lighting can be plugged in by a film crew without running line cords all over the floor.
Your talent and PD will appreciate the planning. You’ll appreciate it, too, when you’re not running around at 4 a.m. trying to gather things together for a 6am party.
Got suggestions of your own? E-mail them to me for SBE recertification credit.
Submissions for this column are encouraged, and qualify for SBE recertification credit. Fax your submission to (703) 323-8044, or send e-mail to email@example.com