Dielectric's Matt Leland sent in an entry for the worst transmitter site road.
Seen in Figure 1, it's a shot of the Cox Radio transmitter site in Hawaii. A beautiful location and view, but forget the road; access is via helicopter!
Matt Leland can be reached at firstname.lastname@example.org.
(click thumbnail)Fig. 1: Don't bother driving to this transmitter site.
Don't you hate to lose or misplace parts when you are disassembling equipment? Joe Stack has a cheap solution. Joe is a frequent contributor to this column, always ready with a great idea that will improve your efficiency as an engineer. His latest submission is no exception.
(click thumbnail)A pillbox sorts small parts for easy reassembly.
The seven-day pill organizers that you can pick up in the dollar store are handy during disassembly of a device for storing small parts and hardware in the proper order. Referring to the photo, replace the days of the week with stick-on numbers or letters. Flat washers, lock washers and nuts can be put in the separate compartments in the order they were removed from a pc board mount.
This way, the parts can be put back in the correct order. Perhaps this organizer can be used if someone takes apart a tuning or loading control coupling shaft or even a tube socket mount. A lid on each of the seven compartments keeps the contents from dumping out.
In the past, Joe has drawn a diagram of an assembly and, on the drawing, added the letter of the compartment that contains the proper hardware. Beats trying to figure it out later.Thanks, Joe. I've seen engineers use muffin tins to hold parts, but having the snap-on top to keep the parts contained is an added feature.
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Now that most of the nation is experiencing better weather for outdoor activities, AM directional RF proof measurements may be on your "to do" list.
Crawford DOE and RW contributor Cris Alexander offered a couple of great tips on your walk-in measurements. Like me, Cris has learned a few things from now-retired consulting engineer Charlie Gallagher.
A stickler for precision, one of Charlie's cardinal rules was to always pull the measurement rope in the same direction, so it runs along the ground like a snake from one measurement point to the next. This will expedite your close-in measurements. As you measure off each distance, don't try to pull the lagging end of the rope up to the next measurement point. This will form a big loop, snagging the rope and taking extra time to free the snags on bushes and brush.
Instead, have your helper mark the point at the leading edge of the rope, and then pull the leading end of the rope along like a snake, till the next measurement distance is reached. I've tried it both ways, and Charlie's suggestion works.
Cris recalls getting zapped during one set of walk-ins and offers this caution. The cotton rope was wet from the dew on the ground. The farmer who owned the adjoining land didn't appreciate the trespassers, and turned on the electric fence. As the rope draped over the fence, it made a pretty good conductor! Ouch! I'd heard of a similar shocking experienced with a wet rope getting too close to a high-power tower. At least the measuring device wasn't a chain or long wire.
Cris Alexander can be reached at email@example.com.
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The folks at Broadcast Signal Lab in Boston are one of a growing number of firms providing HD Radio planning and installation assistance.
On their Web site, one of the principals of the firm, Dave Maxson, has posted a Kenwood radio application note and a companion Broadcast Signal Lab note on using a special mode in the Kenwood HD Radios to time align analog and digital audio transmissions.
If your plans call for HD Radio, or if you've already converted, you'll want to visit this site. Here's the address: www.broadcastsignallab.com/digital.php3.
David provided a great HD tutorial at last year's Maine Broadcasters Convention. Reach him at firstname.lastname@example.org.
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Although he admits he's not up on all the details, Arthur Graf, CE with KTIS(AM/FM) in St. Paul, encountered a similar problem to one outlined previously in Workbench. His station generator's output frequency floated around enough that the UPS would not accept its power output. Arthur's electrician dealt with this by adding a "frequency governor" of some sort to the generator. That modification cleaned up the generator's output frequency enough so that the UPS would accept the generator's power.
Art admits he's no electrician by any means, but he found our mention of "distortion of the sine wave output of the generators" interesting in light of some recent reading on troubleshooting power quality and power harmonics. Arthur questions the possibility of generators, transformers, etc. needing to be "derated" because of all the non-linear loads involved.
A lot of great power-quality articles can be found on the Fluke Web site. Go to www.usfluke.com , go to Support and click on Application Notes, and choose Power Quality.
And there is a great article on troubleshooting power harmonics at http://support.fluke.com/find-sales/download/asset/1260362_k_w.pdf.
Thanks, Art, for offering such a great resource. Art Graf can be reached at email@example.com.
Submissions for this column are encouraged, and qualify for SBE recertification credit.