Rack Shelf Adds a Second Pair of Hands

Police respond faster to a crime in progress.
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Keith Jentoft is president of RSI Video Technologies in White Bear Lake, Minn. He has been following the comments about copper theft at transmitter sites and writes that his company has developed an affordable solution that is being used by Duke Energy, AT&T and many homeowners.

The solution is a wireless portable video security system that runs on batteries.

When an intruder trips the motion sensor, the integrated camera takes a 10 second video and sends it over the cell network to a monitoring station. Police respond faster to a crime in progress.

You can see actual apprehensions on www.coppertheft.info if you click on “Catching a Copper Thief in the Act.” You can also see a rooftop AC unit being saved in “Videos of Actual Incidents.”

The site has 14 video clips of various types of theft or vandalism. My favorite is the “storage container” showing someone hammering away at the lock. You’ll find the video clips fascinating.


(click thumbnail)Fig. 1: A tricky job — removing a heavy exciter by yourself.It’s obvious the system works and has a proven track record. This is certainly not the only solution to transmitter site vandalism and theft, but it is one with many applications.

* * *

Have you ever found yourself having to replace a heavy piece of equipment, like a processor or as shown in Fig. 1, a heavy CCA exciter by yourself?

Sometimes, just getting the old part out is as hard as putting the new one in. Some time ago Winston Hawkins discovered a way to make this a much easier job.

Winston carries a standard rack shelf with him in his truck. Whenever he needs to change out a piece of equipment, he installs the rack shelf, upside down, in the rack just under the old piece of gear, as seen in Fig. 2.

(click thumbnail)Fig. 2: Screwing the shelf below the heavy equipment provides support.
Using the shelf as a brace, the heavy equipment is unscrewed. With the shelf bearing the weight, the old equipment can be taken out of the rack easily, as shown in Fig. 3. The new equipment can just as easily be installed.

No more balancing equipment with one hand, and trying to unscrew rack bolts with the other. Best of all, no more cross-threaded bolts, since both hands can be used to remove or insert rack bolts. Simple, and it works.

Winston Hawkins is the technical director for Personal Achievement Radio.

* * *

Contract Engineer John Ragsdale had an experience where diagnosing the problem with his client’s STL meant looking beyond the STL.


(click thumbnail)Fig. 3: Rack shelf in place after the exciter is removed.Collocated on the tower with KQSS(FM) in Globe, Ariz., is a pager company, with an antenna about 75 feet away from the STL antenna. The pager transmitter had quit, so John met their tech to let him into the site.

The final PA module failed on the pager transmitter and was replaced. On the way back to the studio, John noticed the station modulation going up and down in level. John couldn’t really diagnose the problem from his digital STL meters, but then it dawned on him that the problem occurred after the pager tech left the site.

On a hunch, John pulled the AC plug to the pager transmitter; the problem went away. Plugged back in, the audio level began fluttering again. John switched to his backup analog STL, which wasn’t affected, and called the pager company. The backup analog STL worked fine, which kept the station on the air until the errant PA module was replaced.

After discussing the issue with Moseley, the station invested in a bandpass filter, to further protect the digital STL input. In talking with Moseley’s Bill Gould, he recommends the bandpass filter on their digital STLs, especially as more tenants occupy space on towers.

* * *

Buc Fitch writes that the best ideas usually are the simplest.


(click thumbnail)Fig. 4: Use clear silicon caulk to safeguard bare AC terminals.Take Fig. 4. Buc used 25 cents’ worth of GE clear silicon caulk to cover some bare AC connections on a terminal strip to guard against electric shock.

The silicon guards against a hot wire popping out of a crimp lug, or someone with a screwdriver accidentally shorting the terminal to ground. Fortunately, most new equipment uses an AC power cord to feed the AC, but you may still encounter the bare terminal block on older gear.

Note the little overrun of caulk on the left — if you ever have to get access to the screws, this little “grab” section on the caulk helps to lift off the useful mess in one motion. This little blob of clear silicon caulk can really save you from a close encounter of the AC kind, in the back of a dark rack at 3 in the morning.

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