Remote Control Technology Has Come a Long Way

The author of this commentary is engineer/project manager for American Amplifier Technologies. This is excerpted from the free ebook “Trends in Remote Control & Facility Management.”
Today I was thinking about the remote control at my first radio job.
We used a 950 MHz STL to send audio and control information to the transmitter site and a 450 MHz TSL to return meter readings. We were reasonably happy to have forward and reflected power readings, the all-important ability to turn the transmitter on and off, raise and lower power, and, of course, a fail-safe wired to turn off the transmitter if the STL were to die.
Beyond that, however, we had to guess.
If the station went off, a lack of response from the remote control probably meant the utility power was off and the generator hadn’t started. But it also could mean the STL transmitter had failed, so we had to stop and look at the STL transmitter before driving to the transmitter site.
And because we knew so little, every time we were off air, we had to pack the truck with parts and tools to fix most anything that might be wrong.
Now we can look remotely at just about everything at the site, well beyond basic transmitter parameters … site temperature (inside and out), generator status, exact voltage from both utility and generator, not to mention live camera views of the transmitter, room and front door.
Depending on what I learn remotely, instead of driving to the site, I might be able to simply shut off and restart power to one rack component to get back on the air. The beauty of current technology is that emergency trips to the transmitter site are rare. Which, honestly, is the core purpose for a remote control system.
The problem with the now antiquated system at my first station is that I could know only a tiny fraction of the available information about the equipment. Fortunately, it’s no longer necessary to view my equipment through a pinhole.

In a time when staff and contractors are working harder and spreading their talents across multiple signals, having a basic remote control is now more expensive than upgrading. Making up for lack of information requires time, and unfortunately, it often means off-air time.
By necessity, most engineers can’t get to the transmitter site as often as they would like, feeling lucky to schedule a quarterly site check and cleaning. Therefore, having more detailed access to information about these critical systems becomes even more important, and allows the engineer to make good decisions about when visiting the site has become a critical priority — reducing the chance that the call to visit the site is an off-air alarm.
Through SNMP, equipment at most stations now provides a wealth of knowledge beyond voltages or GPIO, but not all remote control systems can take full advantage of it.
It’s important to look for systems that can fully leverage the information and control SNMP provides, such as AAT’s EmPower system. Far beyond being able to look at exciter readings, SNMP can provide information about specific devices within the transmitter, show audio input levels, and so on.
Remote control is only useful if the information and control are available where you are. For many years that meant walking (or running) to the remote control to find out what was going on. Now, products like EmPower put everything you need, literally, in your pocket.
Anywhere you have connectivity, you can receive alarms, evaluate readings and adjust parameters. It’s no longer necessary to drop everything to deal with a transmitter site problem — often a few seconds in the app will show what’s going on and allow on-the-fly adjustments.
Security is also an essential component of your remote-control system, as the last thing anyone needs is to give an unauthorized party control over the transmitter.
Security may involve careful implementation of firewalls or other protection options. EmPower uses a secure cloud service, making it easy to control who has what access. Now it’s possible to ask the board op or consultant to check readings or reset components, as desired, while keeping the bad guys out.
Reflected power readings used to be the only way to monitor the health of the antenna system.
For example, water entering the antenna system used to be invisible. It would silently creep in over weeks or months, and unless someone happened to notice a very tiny change in reflected power, no one had any idea. Then suddenly, the station is off the air with catastrophic damage to the inside of the coax, something that’s very hard to fix quickly.
Though AAT is happy to provide coax on short notice, it would be better to know about the problem before it was a disaster — knowledge that reflected power isn’t likely to provide.

To help solve this blind spot, AAT can add vector network analysis to EmPower with its VNA option. The Empower VNA module can evaluate the health of the system in real time — while you’re on the air — and allow you to set alarms that will trigger whenever the antenna system changes from baseline measurements.
Thankfully, guessing what’s happening at the transmitter site is no longer a necessity because remote control technology has indeed come a long way.
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