In his time in radio and television, Dan Slentz more than once has had to explain the effects of atmospheric ducting. It seems the more stations that are squeezed in, the higher the likelihood of a stray signal on or near your frequency being “ducted” down on you from far away.
William Hepburn runs the DX Info Centre Tropospheric Ducting Forecast site. It provides a six-day forecast of potential VHF, UHF and microwave radio and TV anomalous propagation. Colored interference zones are displayed on a map of the United States.
The forecast predicts areas where the necessary atmospheric conditions are present where tropospheric bending of TV and radio waves could occur, extending the range of radio and television signals far beyond their normal limits.
As I write, the map shows marginal/fair interference conditions over Florida, but severe interference conditions from Richmond, Va., north to Delaware. Use the maps from this site to explain to your manager or PD why interference is affecting your signal, and it’s not your fault. Check it out here.
Reboot help
Dan also shared a tip for those of us who maintain translators.
You’ve probably experienced the frustration of having to drive for miles just to reboot equipment because the internet has proven to be less than reliable. Dan recommends installing a device that monitors net traffic and reboots power on the connected AC receptacle. This will restart the cable modem or 5G device if it loses the network.
Proxicast sells the ezOutlet5 here. The single-outlet version at $79.95 is a reasonable solution when one considers the cost of the engineer’s time, not to mention the price of gasoline for a round trip to the transmitter site. There’s also a dual-outlet version; and the company’s MSNSwitch2 has the capabilities of the ezOutlet but adds enterprise-grade features for advanced applications and finer control over various events.
Good ideas? Check.
In October, I told you about the new self-inspection guides for FM, AM and TV that the SBE provides free to members.
On a related note, Larry Wilkins and the Alabama Broadcasters Association offer a free Transmitter Site Checklist, which will be especially helpful for an IT person-turned-RF engineer. It is a comprehensive list to help you get the most out of your next transmitter site visit.
As a former contract engineer, I think the guide would be useful in explaining to a manager what a trip to the transmitter site entails and to document that you are following good engineering practice.
Drop an email to Larry at lwilkins@al-ba.com. And if you haven’t signed up for his Monday Morning Coffee and Technical Notes email, ask him to add you to the list.
[Related: “Self-Inspection Guides Are a Powerful New Tool“]
A Tonne of good ideas
The website of Tonne Software offers “an uncommon catalog of original and useful electrical engineering programs” for Windows operating systems from Windows XP up to Win 11.
You’ll find about 20 programs from Jim Tonne such as Elsie, an electrical filter design and analysis program. Another allows you to design and print professional-quality meter scales on your printer. A Windows filter design and analysis program expedites the design of low- and high-pass filters using standard value components. Amateur radio operators will find much of interest. Consultant Frank Hertel with Newman-Kees Measurements and Engineering shared the site, which is at www.tonnesoftware.com.
Need light? Use your head
Hall Communications Lakeland Market Engineer Steve Tuzeneu writes that when you’re working in the dark and need both hands, a headlamp like the Braun model pictured here is invaluable. Its bright LED lamp can be adjusted to illuminate your work. This would be a great holiday gift for any broadcast engineer. The rechargeable one shown here costs around $35. Find a variety of styles at your favorite online shopping site like Harbor Freight or Walmart.
Don’t break my Windows, Microsoft!
Longtime readers know that they can find many past Workbench columns here. You can, too. These can come in handy even years later.
Broadcast engineer Matt Jones was researching quarter-wave transmission line stubs used in the FM world to protect against lightning damage; he pulled up a column from November 2021 in which we discussed Xenirad’s quarter-wave shorted stub.
In that same article he noticed a warning about using certain versions of Microsoft in automation playout systems because of periodic Windows updates that interrupt 24/7 operation. If you’re faced with this problem, Matt suggests you use a form of Windows called Long-Term Servicing Channel or LTSC. This version of Windows software is meant for automation and use cases where servicing updates will break critical functionality. Matt uses it in commercial and government implementations for system control and automated messaging. Learn more here.
Workbench submissions are encouraged and qualify for SBE re certification credit. Email johnpbisset@gmail.com.
