Last Updated February 25, 2016 I presented a paper at SBE Chapter 22 Expo explaining why Passive RF System Maintenance is more important than ever with the pending FCC repack. Here is a link to a pdf file of the slides. A couple of slides I were added. These slides were deleted from the live presentation to conserve time. I plan a more thorough discussion of vector network analysis of passive RF systems when my schedule permits.
Repacking - The FCC hired Widelity, Inc. to analyze the challenges facing broadcasters in the upcoming transition. You can download the Widelity report here. An important note - do NOT use the table of prohibited channels as an absolute reference.Read more here.
RF System Maintenance - Three different discussions about preventive maintenance for transmission line: The first was with a friend, and well-respected RF engineer with years of manufacturing and field service experience, now working in a differnet capacity, who recommends periodic sweeps to check for watchband deterioration. The opposite opinion, from yet another friend and respected field service engineer appears to let you procrastinators off the hook until post transition, but not so fast! Read the full story here. (Executive summary - You still should conduct tranmission line sweeps to reduce the potential for catastrophic failure. Do you really want to incur a $100,000 repair on a line that may not have a future for your station?) Yet another friend and director of engineering for a station group thinks the preventive sweeps are well worth the expense, and takes it a step further in anticipation of the repack. Have your existing transmission line mapped to determine summing frequencies. If you know in advance where the summing occurs, you can better determine applicability of your line moving forward.
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After years of being the preferred cleanser for IOT transmitter cooling systems, Cascade® is no longer recommended. E2V has a new recommendation. TSP is also still OK. Cleaning should be left to experienced personnel, as IOT damage can result from poor techniques. more»
Often ignored because of its high reliability, failures in the passive portion of the transmission plant can put a station off the air for weeks. More»