What to Do When You Inherit a Dump
by John Bisset
Some good news to report. The station that allowed tower tenants
to share their transmitter building, and installed a "haywire"
rat’s nest of wiring in connecting their equipment, was "shamed"
into cleaning up the mess, after seeing the picture in Radio World!
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| Fig. 1: Take photos of your wiring nightmares so the
boss knows why they’re worth your time to fix. |
Sometimes it’s not that easy. Imagine walking into a site
and being faced with the wire management nightmare shown in Figure
1.
As with many older sites, add-on wiring just happens. We’re
in a hurry, there’s no time to plan, the new equipment must
be installed quickly. Before too long, there’s no rhyme or
reason, and the problem grows.
The biggest difficulty in situations like this is trying to troubleshoot
a problem. If you’re the new guy at the station, the situation
can be daunting.
We’ve all seen sites where 120VAC is run on Belden 8451,
and perhaps encountered the voltage while dyking wires in an attempt
to clean up a rack. (That’s a surprise you won’t soon
forget!) If I’ve described your site, grab your camera and
document it. The pictures will come in handy.
More than one station manager has used an unkempt transmitter
site as grounds to railroad the engineer. Even though the problems
were caused by his predecessors, he had no proof that this wasn’t
his mess. In this day and age of covering your behind, and of management
that won’t take responsibility for poor sites but simply blame
the staff, the investment of ten bucks’ worth of film and processing
is cheap insurance.
Besides, a picture is worth a thousand words, and can be used
to show a GM why you need to spend time at the transmitter site,
or why it took so long to get a problem corrected.
Be proactive. Even if a GM doesn’t understand the first thing
about engineering, no GM would want to hunt through the wiring mess
of Fig. 1 trying to solve a problem. Keep a GM informed of
potential problems to eliminate surprises no one likes to encounter.
Reworking a site like this can be challenging. You’re off
to a good start if there is a spare empty rack that can be used
to hold equipment as it is rewired.
However, if you choose this method, make sure critical cables
are long enough to reach to the next rack. This is particularly
an issue if your site uses sampling line cables, satellite dish
cables or transmitter remote control multipairs.
A nice new rack is useless if the wires won’t reach. This
is a good argument for service loop when wiring – either coiled
in the floor, or above the rack.
. . .
Next, remove any equipment that is no longer needed. The old frequency
monitors may look cool, but if you’re short on rack space,
get ’em out. Remember to leave at least one rack space between
equipment for adequate cooling.
Remember, before removing wires, identify everything. Use cart
labels or numbered wire markers. Do your identification work while
the station is on the air. If you remove a wire that knocks the
station off the air, you’ll know it, and it will be easier
to identify.
It’s been my experience to call the jock and tell them what
you are doing, asking them to call you if they hear anything unusual.
This way, the hum caused by a grounding problem will be picked up
by the talent as you bump against the wire. After all, it’s
doubtful you’d hear the hum with the transmitter blower, exhaust
fan or air conditioner running.
As you work, keep in mind that the code word to this kind of work
is simplicity. As you identify the wires in a rack, draw a schematic
of the equipment and how wires are hooked up. Don’t depend
on your memory.
. . .
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| Fig. 2: This simple shelf is made of pressboard and
L brackets. |
If you’ve inherited a poorly designed transmitter site and
are not sure where to start, one of the first improvements will
be to get things off the floor.
Obtain a file cabinet from the office for your manuals. If there’s
room for one of those small salesman’s desks, grab that too.
Inexpensive steel shelves can help you organize spare parts. If
your dehydrator is on the floor, get it up on a shelf.
Figure 2 shows a simple shelf using pressboard and a couple
of L brackets. Note that the dehydrator is secured to the shelf
with a long nylon wire tie. This prevents the motor vibration from
"walking" the dehydrator to the edge of the shelf.
This photo also demonstrates a nitrogen manifold with valves for
each line, and pressure gauges for each line. Rather than using
a common valve and gauge, this system permits sealing of any line,
should a leak occur, using its own valve. The individual gauges
can pinpoint which line is leaking, reducing diagnostic time.
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| Fig. 3: Leaking line? Start your check at the
gas inlet fitting. |
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If you have encountered leaking line, remember to check everything
on the ground first. Start at the gas inlet fitting on the transmission
line, as seen in Figure 3. Spray a bubble solution at the
junction, while you have pressure on the line. Even the tiniest
of leaks will generate tiny bubbles. Tighten or replace the fitting.
Remember to use Teflon brand or similar plumber’s tape around
the threads of any brass-to-brass pipe screw-on connections. Roll
on the piece of plumber’s tape in the direction you will be
screwing on the fitting (usually clockwise). This will prevent the
tape from unraveling as you screw the fitting or valve in place.
Keep things off the floor and you’ll have a cleaner transmitter
site – and prevent any water leaking from seams in the wall
or floor from damaging your equipment.
John Bisset has worked as a chief engineer and contract engineer
for more than 30 years. He is a district sales manager for Harris
Corp. Reach him at (703) 323-8011.
Submissions for this column are encouraged, and qualify for
SBE recertification credit. Fax your submission to (703) 323-8044,
or send e-mail to jbisset@harris.com
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