Digital Journal—The Coming End of the Analog Era

Last November of 2007, IPTV began a project that will, over the next two years, result in the replacement of 6 of its original UHF transmitters. All six of the transmitters are vintage integral cavity klystron units from either Harris or RCA and are 30 years old or older. I won’t delve too deeply into the apparent insanity of replacing analog transmitters less than 16 months before the end of analog television broadcasting. Regular readers of my column know that the replacement transmitters were purchased with all of the hardware necessary to flash cut the new analog transmitters to digital where they will continue to function as the primary transmitters for the IPTV network. Rather I would like to celebrate the end of an era that I wonder and even doubt that we will ever see again.

Take a look around your facility and identify a mission-critical piece of hardware that is not the building you’re in and has been in continuous service for 30 years. Having a little trouble with that? How about something that has been on line for 25 years... 20… 15? In the modern era of consumable products, there are not too many pieces that aren’t outdated in 18 months, obsolete in three years and no longer supported after five to seven years. Therefore, equipment that is expected to last for decades is no longer the norm but the exception, making it quite easy to fall into the trap of ignoring it until there is a problem. Now, take this piece of equipment and move it to a remote location that may only see an occasional visitor, add wildlife, extreme weather, mechanical and liquid cooling and apply high voltage and you can see that there will be problems.


(click thumbnail)Workers disassemble the IPTV analog transmitterThe KRIN transmitter is our first to be replaced. It is the oldest and, out of all of our UHF facilities, serves the largest population pool. As I was looking at the photographs of the demolition of the RCA TTU-110 transmitter I marveled at the changes that have occurred since this unit first went on the air Dec. 15, 1974 and wondered how was it able to survive this long. Quite simply, it was well maintained.

In the beginning, KRIN, like all of IPTV’s sites, was manned so that skilled engineers were constantly monitoring the systems and performing regular preventative maintenance. A lot of the preventative maintenance was the simple stuff like keeping things clean and lubricated. I am also sure that many serious problems were prevented because the engineers that were intimately familiar with the systems were able to see or hear the subtle changes that precede many catastrophic failures and took corrective action. Although times have changed, even now the KRIN site is one of the locations that functions as home base for our engineer that covers the northeast quadrant of the state. So the transmitter gets frequent personal attention.

The RCA has now been replaced with a new Axcera Visionary IOT-based transmitter and I believe that if we maintain it, in 2027 or so, whoever is the director of engineering at IPTV will be marveling at the longevity of the system.


But given smaller staff size, how can we or anyone work to ensure this type of life expectancy? At IPTV, even though our staff size has shrunk, we are still able to maintain enough people to handle the load. There are times when it is challenging and stressful but for the most part we have the people to do the job.

What is more difficult is infusing in the people—primarily the new people—the recognition of the importance of doing the simple stuff I described above. I only had to deal with one dust-related arc in a tube cavity early in my career to understand the importance of wiping down the tuning surfaces.

I used to find myself amused as I bent over running the shop-vac through the bottom of the transmitter cabinet, searching meticulously for dust and debris and realizing that if my wife ever saw how good a job I could do with a vacuum, I would be doing this at home for the rest of my life.

At every transmitter site I was ever responsible for, on my first schedule maintenance I would do a thorough physical inspection of the entire facility, not just the transmitter, but the HVAC, primary electrical, plumbing and everything necessary for the site to function and make notes of items that concerned me. I would then do repeat inspections on a regular basis, paying close attention to the items I had previously noted to see if there was any change. I always created a metering list and read every meter regularly, even the ones that never seemed to change. On a few occasions I actually did see changes where I never saw them before and was able to correct a problem before it resulted in an outage.

This may seem like busy work to many but for me, it actually served a number of valuable functions that I still put into practice.

Aside from the obvious benefit of preventing problems or catching them when they are small, it also made me curious to understand what was happening, even during normal operations. I would dig into the manuals and research elements which helped me become a better engineer. Probably the most important benefit was that it helped me develop a disciplined approach to maintenance and problem solving which I continue to use to this day.

I also found that scheduling regular trips to the transmitter was very therapeutic and at times almost Zen like. It allowed me to perform useful work while still clearing my mind so that I could better handle the more complex and difficult problems that became a larger part of my career as my responsibilities grew. To this day, I repair tube guitar amplifiers because it allows me think in parallels while simultaneously relaxing and feeling that I have accomplished something satisfying. Peace is where you find it and in the digital era, it is often hidden amidst the ones and zeros.

Bill Hayes

Bill Hayes, director of engineering and technology for Iowa PBS, has been at the forefront of broadcast TV technology for 40 years, 23 of them at Iowa PBS. He’s served as president of IEEE’s Broadcast Technology Society, is a Partnership Board Member of the International Broadcasting Convention (IBC) and has contributed extensively to SMPTE and ATSC.  He is a recipient of Future's 2021 Tech Leadership Award.