Did you ever climb an AM tower? I’ll bet if you answer no, you think that it’s no big deal, right? Well check out this video and maybe you will feel differently. Pretty hot, right, I meant the tower, it’s a hot tower, meaning that if they didn’t put the shorting jumper on it then you would get a serious shock and burn. You can hear the AM when he pulls it off and puts it back on. By the way, RSI has an overview of AM here.
This isn’t about the climbing of the actual AM tower though. Let’s talk about the AM tower’s neighbors. The nearby towers that can be affected by the AM power radiating and causing problems. In what way? It causes the towers to charge and can bring the noise level up. AM radio stations create serious noise for other operators. Oh, and the FCC has clear rules about what you need to do to “detune” your tower if it sits near an AM tower. In fact, LBA lays out the 13 new rules clearly here. Not only to protect yourself, but to protect the AM stations transmission pattern. It matters to the FCC and it may not matter to you unless you are bombarded with noise issues or you get shocked on your tower or maybe, the FCC will send you a citation asking to comply.
There is an entire rule set around AM protection, which LBA also has a course on here.
So if you own or maintain a cell tower and want to remain compliant with the FCC, how do you know if it’s detuned? Well, according to a post by Lawrence Behr found here, you install a detuning system to remain compliant. It matters for so many reasons which I am outlining here, to be FCC compliant and for safety and to minimize noise. It all matters.
If you climb the tower and want to avoid the shocks and burns, then you will make sure you understand the risks when you see a detuning system on the tower. So ask yourself, “Is this cell tower hot?”. That is what Lawrence wrote about here. If you want to see a detuning system, then go to the YouTube Video here and listen to what he is talking about. I also have the video down below.
AM is Amplitude Modulation and in this case we mean AM broadcast. Lots of power in the 540KHz to 1700KHz. band. This may not mean much to you. I worked near AM tower for years and the main thing I remember is trying to filter out Rush Limbaugh from all of my leased lines. Yes, I had many leased lines back in the day and AM would bleed into everything. However, I digress, let’s get back to the issue of hot towers.
Well, AM towers have been around for a very long time so this is something that you may want to learn about. If you climbers ever climbed a hot tower then you know that there is a process to climb it. They will either turn down the power down or you make the leap onto the tower. If it is live, then you feel the hot spots on the tower. The LBA post has so many good tips in it.
Detuning is probably something that most of you never think about. An important aspect here is that Compliance with the FCC. If you climbed a tower that has large ground wires run down the sides, then you probably saw the tuning systems. They generally stick out form the tower a few feet. It is very obvious. I am not talking about the ground wires that you tie tight to the tower. The large wires on the detuning system makes the tower look “invisible” to the AM pattern so it does not interfere (too much) with the radiation pattern. However, if you touch them you may get a shock! For more on AM detuning, go to https://www.lbagroup.com/ and let them know that Wade sent you there!
By the way, LBA just appointed Gary Doyle as the new VP and General Manager of LBA’s safety training unit, LBA University, Inc. (LBAU). Congratulations to Gary.
So when on a hot tower or a detuned tower, what do you need to be aware of? Do you know if the detuning system is working and tested? Call the tower owner and ask. Do you need isolation hardware to mount your hardware? You may need help. Make sure you understand the site design. Make sure the installation crew knows all about the tower before they step foot on site. This is why LBA consults for something like this, to avoid the problems before they happen.
If you are mounting RRHs, make sure you know if they need special grounding or isolation. You may need isocouplers, which should isolate the equipment properly. Find out up front. They have an article on their Tunipole if you’re interested.
This is another hazard you need to be aware of if you are climbing. If you are working at the tower then be aware of what could zap you. If you are commissioning, be aware of the noise you are dealing with. If you are aware of not only your tower, but the nearby towers and the problems they may be causing you, then you are one step ahead of the competition!
Be smart, be safe, and pay attention!
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