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TTT Site Maintenance Q&A

Hey folks – welcome to 2021. It’s currently a touch frosty here in the frozen north, but the days are getting longer and it’s time to start planning spring maintenance runs. With that in mind, on February 9th we started the 2021 series of TTT (Transmission Talk Tuesday) roundtable discussions with a Site Maintenance session. It was a great start to the season, with over 150 folks in attendance to talk about their favourite tricks for making maintenance runs less eventful and more productive!

On the topic of the TTT sessions, when you register, there’s now a spot on the form where you can indicate any questions you’d like to see addressed during the session… this proved to be much more popular than we could have hoped and I apologize for not getting to all of the questions asked in the Site Maintenance session – I tried, but I know I missed some. With that in mind, I’ve culled the list and anything I didn’t get to in the session follows…


First, somebody asked how to get into their NV40 transmitter when the door latch is broken and spins freely. If I had to guess, I’d say the screw that holds the handle to the latch assembly came loose and the handle popped free of the latch. If that’s the case, about the only option is to lift the door free of the hinge pins by levering it straight up, and gently pulling it free that way – there are cables going from the chassis to the door on the left side, so be careful, but that should get it far enough open to allow somebody with long arms to reach in and work the latch free from the inside. I’d use a strip of wood on the bottom of the door to keep it from getting mangled, then use a flat pry bar to lift it slowly and carefully toward the hinge side, something like this:

photo courtesy of homedepot.com

It is a challenging situation and not something we encounter on a regular basis, but the hinges are a drop-on type, so lifting the door enough to clear them of their pins should enable you to get in and get it unlatched, at which point you’ll be able to take a good look at the latch assembly and sort out what needs to be done to prevent it from happening again!


One other question was along the lines of what to do if you lose the host connection to the transmitter. I’m assuming this means you can ping the AUI, but it’s locked up or whatever and you simply can’t log into it. There are a couple of things that come to mind as possibilities here. First, if you’ve got a conventional remote control, we do have the ability to force a host reboot from the remote inputs – you do need to program this function to one of the remote control inputs, but then you can use a conventional remote control to reboot the AUI. Most of the time, unless there’s an actual physical problem, this will get things going again – do the reboot, wait 2-3 minutes, then try to log into the AUI again.

If you don’t have a conventional remote control, another option is an IP controlled power strip, and use a power supply plugged into it to fire a relay wired to the remote input that’s programmed for Host Reboot. Then, if you can’t get into the transmitter, log into the power strip, cycle power to the outlet with the relay connected to it and you’ll send a reboot command that way. The IP controlled power strip is also useful for any other devices that occasionally need a restart to run smoothly – some of them will allow you to control individual outlets or the strip as a whole.

Above is an unit made by CyberPower that would do the job nicely, there are many others available, ranging from a hundred dollars to a lot more, depending on the brand and what you wish to accomplish.

AM vs FM

Next up was a question asking if I could compare maintenance at an AM site vs an FM site. Really, the only critical differences are in the antenna system. On the FM, you’ll want to look at ground kits and cable brackets going up the tower, as well as getting the binoculars out to take a good look at radomes, if used. On an AM, you’ll be inspecting the ATU(s – and phasor for a directional), as well as making sure the ground radials survived the winter and didn’t get stolen – more info on tracing ground radials can be found in this previous Tips article. Beyond that, tips for generators, air handling systems, critter control, are pretty much the same for any site, whether AM, FM, TV or your ham shack.


Another question that came in, and one that comes up a lot, is how often should the gear be opened and vacuumed out. My answer to that is virtually always the same, “It depends”. How often air filters need to be replaced and gear cleaned will be determined by site conditions and could vary from every few weeks to every few years. The best answer is to set a schedule that works best for your particular site – and it may be different from one site to the next within the same group, again depending on air handling, whether it’s air conditioned or not, whether it’s an office building or a shack in a hayfield, etc. I’ve done several Tips articles on cooling and air handling including the one linked above (see full archive here). Definitely finding what works best for your particular scenario will go a long way toward determining a realistic cleaning and maintenance schedule.


As any regular reader knows, we focus a lot on safety – as the saying goes, nobody ever died from a lack of rock’n’roll – taking the time to pay attention to doing our jobs safely is critical. On that topic, Engineer Benjamin Labaddan, retired from FEBC Philippines, was kind enough to share a booklet he wrote on safety during his tenure as a staff engineer. I’ve taken some excerpts from that document and added my thoughts:

On psychology:

“Our overconfidence in doing a certain thing repeatedly could make us prone to carelessness.”

This is quite true – it’s the things we’ve done a hundred times that bite us in the rear, as things get so automatic that, when something does turn up out of the ordinary, we just keep on rolling. It’s definitely crucial to take the extra time to slow down and be certain that our memories of how things should be aren’t deceiving us.

On site safety:
“Do not put obstructions on the way towards the safety switches and circuit breakers” and “Never leave the live safety switches or wires uncovered.”

I’ve lost count of the number of sites I’ve seen with circuit breaker panels open and uncovered – it’s a lot. The times I’ve pointed it out, the response is typically, “but I’m the only one here”. My answer is that is the exact reason why it is so critical that the panel be covered! 120V may not be an issue for some, but once you get up into 240V or higher, there aren’t always second chances.

Also, “Always remove the temporary door interlock bypassing clip leads before operating it. If that is not practical at the moment, a warning sign must be put on the door.”

There was a conversation recently on a Facebook engineering group about this exact situation – a safety interlock that had been bypassed with gaffer tape and left that way… any time you walk onto a new site for the first time, assume every interlock has been bypassed until you prove otherwise!

There were more notes and good points about PPE – safety shoes, goggles and gloves, all of which made for a great resource – thank you Engineer Labaddan!

If anybody else has any tips, notes, photos or other things they think worthy of sharing, please feel free to pass them along – if I can’t fit them into a weekly webinar, I’m always looking for additional material for these articles.

On that note, folks, let’s all take care out there and I’ll see you next time – until then, be safe and happy engineering!


Jeff Welton, has worked with Nautel for 30+ years. He is currently the Nautel Sales Manager for U.S. Central Region but previously he spent 16.5 years as a Nautel Customer Service Technician. A regular speaker and contributor on broadcast engineering, Jeff has been recognized with the following awards: 2020 NAB Radio Engineering Achievement Award; 2019 APRE Engineering Achievement Award; and 2018 SBE Educator of the Year Award.

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