Can’t See the Tower for the Trees

Backups are great – when they work!...Winter’s elements can force dependence on a generator. If the operation is not monitored, however, disaster can strike.
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Backups are great – when they work!

Winter’s elements can force dependence on a generator. If the operation is not monitored, however, disaster can strike.

By allowing a diesel engine to run out of fuel, for example, you can cause a costly fuel injector cleaning. A good way to guard against such a problem, in addition to monitoring fuel levels, is to install a two-stage fuel filter.

Thanks to Ed Bukont with Commstruction, a division of Total Engine Sales and Service Company in Baltimore, for this timely tip.

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(click thumbnail)Fig. 1: Protect elements from the elements!The elements can make any engineer’s life miserable. How do you guard against this?

In Figure 1, the satellite waveguide might better serve as a birdbath as its open end fills with water.

Take the time to place a small plastic lunch bag over the waveguide after the LNB is removed. Tape up the coax pigtail as well. The rusted bolts will only make replacement of the entire assembly more difficult.

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(click thumbnail)Fig. 2: Combo LockMaintenance around the transmitter site includes your security systems. For most of us, this includes key or combination locks.

Squirt a little liquid graphite or lock lubricant in the locks and working the mechanism. This can thwart the effects of icy weather.

If you’ve got combination locks, like the one in Fig. 2, set all the tumblers to 0-0-0-0. This tells you if anyone has turned the tumblers and frustrates would-be vandals, who might think your combination is just a few numbers away from a random combination setting.

By the way, this particular Master-brand combination lock is worth its additional cost. The combination can be reset easily, meaning staff changes or tower lease expirations don’t require wholesale lock replacement.

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At a recent SBE Ennes Workshop, we discussed safety items to keep on hand at a transmitter site.

One suggestion was a flashlight, mounted right inside the transmitter site door. Another engineer did one better: a wind-up flashlight.

These are great and they’re affordable. One store, Restoration Hardware (which, despite its name is really a neat household gadget store) sells them for $15 to $20.

You squeeze a ratchet-type handle, which works the generator to light the flashlight. No dead batteries!

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(click thumbnail)Fig. 3: Get out the weed whacker
So, how does that old adage go, "you can’t see the forest for the … tower?"

Fig. 3 is a good example of out-of-sight, out-of-mind. This "forest" didn’t just spring up overnight, although the owners of this station might like the FCC to believe that.

Yes, the trees are inside the tower fence. GMs, this is why your engineer must visit the transmitter site once in a while.

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Older engineers may remember the Heathkit-brand pain-can dummy load, called a Cantenna. These loads can be found at hamfests, and are useful for testing.

Take a look at the power rating the Cantenna provides, based on two types of cooling oil:

Power Xfmr oil Mineral oil

1000 W 9 min 1 min

750 W 13 min 7 min

500 W 23 min 18 min

250 W 45 min 45 min

The curves converge at approximately 350 W for 33 minutes.

Thanks to Jeff Zimmer with Family Stations KECR(FM) and KFRN(FM) for providing the reference information for this reasonably priced piece of test equipment.

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We’ve all wished for an extra hand now and then, but who would have thought the lowly clipboard would come to our rescue?

Chris Kelly, CE of the Clear Channel group in Salisbury, Md., makes sure there are clipboards in his shop, toolbox and transmitter sites.

The metal clip does a great job of securing both audio and RF connectors so they can be safely soldered, as seen in Figure 4. Squeezing the connector in the jaws of a vise, or worse yet, a desk drawer, will only result in solder spatters on your pants.

(click thumbnail)Fig. 4: It’s a clipboard. It’s a third hand.
Chris has chosen both a standard-sized clipboard, as well as a smaller version to keep in the toolbox.

By cutting a small groove along the perimeter of the clipboard, the connector shells won’t roll off. By keeping the shells on the clipboard as well, there’s less of a chance that you’ll solder the wires and forget to slip on the connector shell.

But, hey, who does that?

Submissions for this column are encouraged, and qualify for SBE recertification credit. Fax your submission to (703) 323-8044, or send e-mail to

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Cellphones in Them Thar Trees

From the "why didn't I think of that" department: Have you spotted the new cellular "trees" sprouting up across our country? I guess these are in response to environmentalists who feel that regular cellular towers are ugly.

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Trees That Grow Over Night

Fred Greaves, Jr., is director of engineering for Susquehanna Radio Corp., and got a chuckle over our comments about FCC inspections and the inspectors. Fred adds a tip for chiefs of AM directionals.