I have been doing volunteer work for the last couple of months or so, improving a church sound system. I'm going to omit a lot of details that don't relate to EMF, but one of my major tasks was to figure out how to connect eight wall-mounted "fill" speakers that had been disused for possibly many years. I connected a tone generator ("toner") to one of the speakers (actually, to the line side of the transformer; it's a 70 volt system) and traced the signal to a large closet in the far front of the building where, apparently, the original sound system had been located ages ago.
The new location for the mixer and amplifier was in the rear, in the balcony (originally, the choir loft). In terms of cable run, it was about 100 feet from where the fill speaker cable emerged from the wall in front, and I needed to find a way to bridge that very large gap. I used a wireless connection at first but it did not work well, for reasons that are perhaps more obvious now in retrospect.
Already, I was noticing something unusual with the toner -- the pickup was receiving a lot of hum in certain locations around the sanctuary (this is where EMF comes in). The same opening in the wall contained not only the speaker cable but also a heavy gauge 5-conductor unshielded cable and three shielded microphone cables. The shielded cables had been cut off at the other end, and were sliding down the conduit into the closet, so I pulled them out. The 5-conductor cable resembled another I had seen hanging out of the wall not far from where the mixer was located. I used the toner to confirm that these were, in fact, the two ends of a 100 foot run from the front to the back of the building, and I was able to use it to make my connection, though I had to do it the hard way by running small-gauge speaker wire from where the cable came out, along the ceiling, through a door, and up the wall to the balcony. That should have been the end of the story and except for all that hum, it would be.
The hum was exceptionally strong at the back of the building where the 5-conductor cable emerged from the wall. Without going into too much irrelevant detail, I was concerned that there was 120v in the same box with the speaker cable. It turns out there was not, but the EMF level in the wall box was very high. I had of course checked for any voltage at all on the cable I was working with before I connected the toner, and there was none. My concern came from the fact that there were individual heavy gauge solid copper insulated wires in the box, connected to what looked like a second identical 5-conductor cable using wire nuts. It turns out, however, that what I was seeing was just the other end of the same 5-conductor cable that I was connecting to -- I could have connected to the copper wires instead and pulled the other piece out of the wall. The situation was the same at the other end, with the copper wires being spliced to the 5-conductor cable. (More about this loop of 5-conductor cable later.)
I had another problem to solve in that the mixer was picking up radio stations. I checked out the microphone cables using the toner, verified that the connections were correct, and then out of curiosity tried to trace where they were in the walls (still looking for a better way to connect the wall speakers), but the heavy EMF prevented me from doing that. It was strongest along the south wall at the back, and near the ceiling in the narthex (at the rear, the entrance to the sanctuary). At that point I tried replacing the pulpit mic (a gooseneck condenser mic) with another one, the RFI problem went away, and I was done. The EMF, though, seemed spooky, and I wondered if they had grounding problems or something like that. Little did I know...
There was an unusual walled enclosure outside the south wall at the rear of the sanctuary, and it was obvious that much of the EMF was coming from there. (Do you see what's coming now?) I didn't pay a lot of attention to it at the time, but it looked a bit like a small electrical substation. What one of those would be doing at a church is a question I failed to ask. (Those are the questions that get you.)
This all took place around the beginning of August. About a week ago I noticed a sign on that enclosure warning that it contained a backup power generator. At the time, I thought how odd that a church would have that. I was REALLY not paying attention. Later that day, though, it dawned on me. As if the AT&T logo on several outside electrical boxes wasn't enough of a clue. For that matter, someone had told me a week after I finished the earlier work that there was a cell tower located somewhere on the church grounds. I just completely failed to make the connection. And until yesterday, I never noticed the bundle of large coax cables coming out of the top of the enclosure and entering a rectangular duct, that then entered the side of the church at first story ceiling height. From there it crosses inside the narthex ceiling (possibly through plenum space), passing the wall box where I noticed the heavy EMF, and continuing on to the steeple. The antenna array is concealed inside the steeple. It is maybe 20 feet north and 20 feet up from the mixer in the balcony. I also noticed the sign on the gate of the enclosure, identifying it as belonging to AT&T Mobility.
I guess the reason I took so long to notice is that it seems insane to me to locate a cell tower inside a building like that, and I am just not looking out for insane things like that. Two of the congregations that meet there have aging populations, and any number of members that are not well.
After originally noticing the EMF I warned a friend of mine with MS not to sit along the south wall, but now that I know what this is, that doesn't seem like enough. The hum I heard from the toner transducer was not a clean 60hz hum. It contained any number of other frequencies. I'm not sure what it sounded like now, because in my mind at the time it HAD to be from power lines and I wasn't considering anything else. Now it occurs to me that it could have been dirty power but, actually, what I was picking up included direct emissions from the equipment and antenna cables and it didn't have to be any particular frequency, so who knows?
I am concerned now about my speaker connection at the rear wall box. It has that loop of cable in it, perhaps a couple of feet long, that lies very close to the antenna cables. Obviously, the EMF from the antenna cables is not particularly well contained. Is the loop acting as an antenna, and sending something onto the speaker cable in both directions? Or is just passing near the antenna cables enough to cause pickup? For that matter, there is a run of speaker cable across the narthex that connects the left-hand wall speakers to the right-hand ones, and it parallels the antenna cables for perhaps 20 feet or more, and probably lies just a few feet away from them, against the ceiling, but in terms of cable run length, it is perhaps 200 feet downline from the wall box (altogether the speaker cable runs about 400 feet) even though it passes within a few feet of the box.
I am kind of freaked out about this. I spent some long days working in there myself, and almost nobody who comes to the church realizes that there is a cell tower there, let alone that there are significant EMF levels. The host congregation (the one that contracted with AT&T) is somewhat protected in that they have few members left and they tend to sit toward the front, away from the main sources of EMF and still within the shadow of the antenna array. There is small group, though, that likes to sit right through the wall from the equipment enclosure. I'm sure the income from the cell tower is part of what keeps the place going (they rent to six other churches altogether, although only two others meet in the sanctuary where the cell tower is located).
The other church service fills the entire space, including the balcony, and there must be considerable EMF exposure. A third service meets after that and is again a smaller group, and they close off the back rows. Their main health concern might be hearing damage from the loud music.
I have questions, but I am not sure where to begin. How about "Is this nuts or what?"
