Exploring a 1 MILLION Watt FM Tower

today we're taking a gearling engineering road trip to the super Tower [Music] so the super Tower this uh I noticed that there's hundreds of cables I don't know if the hundreds at least dozens of cables coming into it you know a lot of times I see Towers like this and you just think like there's one antenna or something but obviously that's not the case there's not this case in this one so what like what's going on here why are there so many cables what we call this the super Tower back from shortly after it was built because uh back in the uh 50s 60s 70s mostly there'd be like one purpose for the tower an AM Tower FM towers and this one was built to do a lot and it was built to do multiple FMS into the same antenna so that became a thing when uh people started building houses around our antenna sites and we wanted to be in the center population so we made a single Tower put a bunch of stations on it it solves the problem instead of having 10 or 12 Towers in the landscape around us we have one Tower a super tower that does a lot so number one the FM antennas are at the very top and it's it's two antennas combined 10 radio stations now broadcast in that give great coverage to the market it's super coverage actually so again the super Tower and then the rest of the signals are either independent services that just happened to locate here 911 FBI whatever they would have here whatever the tower owner can sell and lease and the rest of it is supporting the broadcasters so there's data exchange internet connections satellite receives a lot of two-way operators can be here cellular is on there so I noticed on on the base here it's really really narrow for all the weight that this tower has I don't know how that's even physically possible yeah but I also saw some grounding straps or something here can you explain what those are for and I remember you at an AM station there was something different about the way that this works but like what's this for yeah so on the tower the grounding is number one some antennas the grounding system here is for safety uh lightning ground so you want the the lightning to hit the tower come as fast down as it can and get to the ground and not try to travel into the building or along any cables so every every cable that goes up the tower is grounded to the Tower and the tower is grounded with a system here with multiple rods around the base this piece is is is rounded underneath it's rounded and sits on a place and some of them have a list of little cup spot but that's the hole but it allows the tower to move if it has to and if you look up you've got the guy wire systems actually pull hard to create great pressure right here so there's no movement so the guy wire system is critical to have the right tension the right cable and all and the right points of contact so that the the system is pulling equally on every leg and this this point here is pulled straight down whether it's a rack of servers or not or it's a bunch of equipment on a tower everybody thinks about Cable Management so you can see here the cable management goes in some go down some go straight in and of course in the building you got the same thing so we can go inside and see what's on the other end of a lot of these cables come on in you can already see some wires are coming overhead here I'm guessing other ones go back if you go you come into this room here so you can see a lot of the cables that come in here and you can see the big Master FM antenna system the cables come through here to go up the tower those look serious are they like pressurized they are pressurized and they're carrying like in kilowatts the antenna radiates almost a megawatt right it's a good set an eight nine nine hundred and something thousand Watts but inside the RF going up is probably 300 or something like that we went inside the transmitter room for one in the eight a 90 000 watt FM station serving St Louis and I asked my dad to explain how the sound comes into the building and how it goes from the studio all the way through to that million watt antenna system out on the Tower or from underground fiber audio comes into this place and by now in a current day all the audio is processed before it gets here because it's digitized so you don't have to worry about any artifacts getting introduced in the path so you have digital audio coming across from the studio wherever it is on the planet and comes into this room uh transfers over and it'll it'll go uh one set of audio will go to the HD transmitter and one will go to the analog transmitter and the HD transmitter is often is a pre-done group of packets all IP that just goes into the transmitter you can see these are the two HD carriers that are being sent out of the transmitter there's no analog carrier which sits in the middle so the analog carrier at this site is sent from a different transmitter and they're mixed at the antenna up on the tower so this transmitter is a water cooled transmitter this particular one you can see the water system there but the copper pipe is the uh as a transmission out here it's about 30 thousand watts of RF to come out and it'll go through a switching system it goes through a switching system and a dummy load for testing goes downstairs into the basement both of these transmitters go down and obviously the HD carriers use a lot less total power that's why they can use a smaller cable but you got a 400 amp service comes in the building we got a generator switch over there to switch in either the building power or the generator power some sites like this will have a single site generator it'd be like a megawatt generator but when this site was built each station was on their own and they still are so you'll see multiple generators out here different sizes depending on what the needs of that station is or that company and a Transformer here I don't even see that one a Transformer that takes that 480 down to the levels we need it to be and then it feeds this group of panels big switches for uh that feed all the transmission transmitters racks so let's say the power of the building is cut so this you can Castle kick in right away and then run both of the analog and the digital and everything else it won't run the analog transmitter because that alone is that would be too much to have one and remember this service is three rooms here so this is all the computerized and audio gear keep it running so the transmitter will be up when the generator kicks on 10 seconds later and everything will be back to normal this basically keeps the audio running but the transmitter will have to kick off and then kick back on when the generator kicks in yeah all the audio gear and the remote control gear which is all computerized now it's all IP based stuff so back in the back corner here I see the two types I'm guessing one is the main analog and one is the backup analog and then it looks like HD just kind of goes right past that weird little R2D2 bucket right right yes what does that do so this is a switch to allow us to switch either transmitter out to the load which it goes down out to the antenna which is down here the other transmitter comes out the other port and goes to our dummy load it's a 50 000 watt dummy load so we can be testing and preparing one transmitter while the other one's on the air and you said there was one dummy load that's actually outside this is a dummy load that used to dissipate a lot of RF it would get very hot and so the wise engineer of this company put this baby outside weatherproof box gets hot doesn't keep the room up or he has to air conditioning because I'm guessing if you pump 50 000 watts into this thing that probably gets fairly when you're testing all of a sudden both air conditioners are run at full power to keep it cool in here because you're dumping 30 kilowatts into that dummy load and it's just it's a bunch of resistors in there it just gets hot like a toaster so we have in this particular transmitter a rare siding of an FM transmitter that is water cooled TV guys have done this for decades but it's kind of new on the FM side you've got two pumps but you got an in and out there's a it circulates out and most of the heat gets dissipated out there through a fan system and then the water comes back in goes through the transmitter goes back out gets pumped through the units out there so we keep an eye on the intake and output pressure and you have two pumps either one can make the system work and just like on your furnace downstairs you've got a little bladder control thing to help you with the water we have two transmitters and two antenna systems one is the main antenna if they're ever working on that y98 here it has actually a second antenna on the tower and so we have it takes two switches to switch the two transmitters to either antenna and then one of them is always end up in the dummy load one of the antennas on the on this Tower one of many feeds these receivers through those filter cans we talked about which we have sort of spare stuff down here you can see these used to be the standard way we would do live broadcast we'd be out in our van whip up that mass shoot it to hit the antenna on the tower to come through here go through a circuit back to the studio and we would pot it up and be live so with these frequencies were the ones that were we used to do our live broadcast so I see that the like the little pipe coming out is teeny tiny it gets bigger and bigger and then all of a sudden there's this giant power monitor yeah how why is it all these weird pipes like usually when I see copper like this you think water yeah so the the cable uh this cable they all has loss right so when you leave a transmitter at 600 watts if your cable is too small and the loss is too great you got to run a couple hundred feet you might only have 80 or 100 200 Watts at the other end of it so you want to have some sort of calculated loss so in this case a bigger line was chosen for the long run down to the basement and across to the antenna you could follow the path from the transmitter to see this one so transmitter two is going to dummy load transmitter one is going out to here going out to here and up to the main antenna all right so we're in the basement of the building and you remember upstairs where the pipes went through the floor so we're going to pick that up here and you can see the thicker pipe the three inch is the analog transmitter and then the HD transmitter is a little stuff there and you can follow these and they will take you probably over here to this box so every station upstairs has a combiner module so they can mix together and form one RF path for all the stations up the tower so if you look down here where the the end station is the inputs go they add up as they go along so down here you got smaller cable jump ring in and out and then all of a sudden you need a bigger cable you can see at the very end it's the huge piece that all the energy of all the stations is going into that Port so this system is also an antenna switcher it just has more RF to deal with so you've got the uh this is actually a switch so if you get I don't know if you can get in there and see it but there is the four port switch just like we saw upstairs for the stations only this is like a nine inch version of the same thing so you can see it's got a controller here so that we can switch the analog and the digital antennas upper and lower and so we switch them through this thing depending on what trouble we're having up there or even if we're just having regular maintenance at the top of the tower but this is version three of the monitoring system and so all the stations here that go in uh this monitors their forward power coming into the system it monitors all their output power on another screen it's going out the antenna triggers alarms and alerts people individually or as a group to issues that are going on out here you said that there's a megawatt at the antenna but adding all these numbers up doesn't quite get there yeah so so the antenna system on this tower has a gain factor it's probably around four and so uh the number of Bays on an antenna go from you know you put a kilowatt in you get a kilowatt out of coverage but if you have two or three or four Bays you can you can increase the amount of coverage you get putting on the same amount of power in you get a rare look at the end of a u used a piece of this coax so just like your coax you use for your car antenna or radio or whatever you've got at home that uses coax outer conductor interconductor and then these are Teflon spacers to keep it in the center and then air flows through as they're usually pressurized to keep them dry so there's no arcing so you mentioned that there's air inside of that tube inside of the coax giant coax tube even a dry air but you need it drier so that's what this is for that's what the nitrogen so these are all nitrogen tanks and because there's so much line and it's so big we have multiple tanks backing each other up you can see everything is monitored they're monitoring the upper two uh the analog 2 and the digital two cables that go up the tower monitor the pressure making sure it stays within the realm where it's supposed to and they end up going out the out the plastic at the top and they go all the way across to the lines over there Connect into the lines that go up the building and outside so here's where they're injected you can see the injection points yeah of the line and each one has a little pressure monitor yeah a secondary monitor if your electronics goes dead computer goes dead safety is a major concern with a tower that pumps out a million watts of RF and just like with electrical systems they have special RF lockouts to make sure tower climbers don't get killed when they do their work so these are for the upper and lower half of the antenna So the antenna system has two four bay antennas and when everything's right they're both on they're both working but if something happened to one or the other a leak in the line up on the Tower or a bay that arced out then they would shut down that half and all the stations would still transmit but only through half the antenna or the upper or the lower half the purpose of this guy is safety for tower crew mainly it's a lockout when you pull this you actually run a short across the inside of the conductor so you would have a lot of small Oak and fire if that if everything was on so the idea is everything's off and it's going to stay off so once they pull this lock them out when it's locked out no one can turn their transmitter on without seeing a short and so the transmitters these days shut off real quick and it's all good so they got a connection Point outside comes underground comes into this building and it distributes this power bus inside of here and then over the years they've had to add a couple more meters then they got main building distribution points here to get power to the cooling and other systems in the building so you know there were a lot of big stations and big coax and Big Stuff there's also as you can see coming in here a lot of smaller stuff comes in and these are for different kind of communication devices everything from two-way radios antennas digital two-way radios small FM transmitters from 1985. this is the communications area that comes comes in from companies like at T and so forth and goes out to all the rooms upstairs and downstairs and so you could see the Aging you know we had the T1 era uh with a copper era it was started with you could see that disappearing uh and then T1 and now we got fiber everywhere no no no no no no no no no no nobody plugs into the UPS's that are for a specific purpose right so no you don't just plug into a UPS because that controls the fiber for the whole building yes that would be the fiber probably for the whole building probably on that UPS yeah five or seven or so another major safety feature is the tower lights at night time it's impossible to see a tower if the lights aren't working so my dad showed me one of the burnt out bulbs and talked about how they make sure the lights are always working these tower sites have lights for safety they get monitored and nowadays there's centers around the country so you sign up you register you put your lights in to be monitored or you have someone locally the local Engineers monitored the super Tower technically called the FM Master tower has a lot of history and my dad was one of the engineers there at the beginning I asked him a little bit about how things changed over the years so when this Tower was built that was around the time I was born were you involved in setting up the initial stuff that went on to it yeah yeah I got involved in it I remember standing over there when they dug the hole out the first the building was empty except for four rooms so you had everything we just walked through the basement had about a third of what sent down there now and there were like four rooms that had activity the rest of them were just blank rooms and it's amazing to me to see so all these cables and all the antennas all these satellite dishes when we went through here there was like a TV station that came and went there were radio stations that have come and gone yeah some of them have switched from using satellite for sources to using IP over the Internet yeah some are using 4G there's little you call them mushrooms little antennas Up on the Roof you can barely see a couple of them for GPS and things yeah so all these different things come and go but I think it's amazing how one Tower the super Tower can have tens dozens I don't know over the years hundreds of different antennas and Transmissions go through it yeah a lot of dreams that started big and then failed but a lot of dreams that came true and and served their purpose and they're done so uh but they do that's a constant thing every Tower owner which is now that they're usually bigger companies but every Tower owner has had to do that when a guy leaves your Tower do you take his cable down do you leave it up for another tenant maybe rent it so this site's been very good about keeping track keeping an eye on it rebuilding redoing maintenance all that stuff so it's been a it's what we call it the super site super Tower St Louis's super Tower

Channel: Geerling Engineering

Views: 414,200

Keywords: radio, saint louis, stl, y98, kezk, tower, transmitter, nautel, be, broadcast, engineering, electronics, fm, am, frequency, receive, transmit, send, data, audio, audacy, stlouis, safety, climber, mast, marti, remote, podcast, behind the scenes, tour, walkthrough, guided, dad, son, teaching, learning, kshe, bull, joy, modulation, fcc, klou, now, arch, z107

Id: 6_u8x8V4YYs

Length: 18min 30sec (1110 seconds)

Published: Fri Nov 11 2022

Reddit Comments

[u/GingerMan512]

In Austin, we're lucky to have several on a TV antenna.

Buckman Mountain – KLRU/KVUE/KEYE Tower

The Austin Repeater Organization gained access to the original KVUE-TV tower and KLRU-TV building in the early 1982 due to the relationship Sanford Musgrove (W5FIT- SK) had with the two stations at the time. The 146.94 Repeater and the 224.80 repeaters were housed inside the KLRU-TV transmitter building. In 2011 the KVUE analog tower was removed from the site. KVUE and KEYE agreed to allow the AARC to move antennas onto the jointly owned tower that is located on this site plus the addition of a UHF repeater system antenna. 660 feet of 1 ¼ inch hardline and antennas were acquired by the AARC to support the move activity. Rack space was provided by KVUE in their building for AARC hardware.

All three AARC repeaters share the single feedline to the 500 foot level of the tower. The AARC owns duplexers, controllers and couplers at this site to provide exceptional coverage of Travis County and parts of surrounding counties.

444.2 Repeater – A UHF MASTR II repeater was donated by KVUE and added to the two repeaters that existed at the site. The Austin Repeater Organization had a coordination of 444.2 that was transferred over to AARC for this site from a location in South Austin.

In 2016 KVUE provided the connection to a UHF antenna the station has at the 950 foot level of the tower for use by the AARC 444.2 repeater. A MASTR II remote receiver was acquired by donation from Paul, KE5ZW and placed in the building at the top of the tower. This shared use of a KVUE antenna providing commercial communications for the TV station is the result of strategy and planning that took over 6 years to materialize.

[u/myself248]

Wow, the combiner network in the basement is insane!

Former cellular tech here, so I've visited my share of towers with other services on 'em (we were one of those other services), but none so massive as this. Thank you for this incredible behind-the-scenes peek!

[u/3x35r22m4u]

I find really interesting that in US there seems to have tradition or preference on using guyed towers for TV and FM stations. Not sure, though, if it's because large areas of the States are plains with few hills or real-state is affordable.

Here in Brazil, guyed towers are used mostly by AM stations or small companies (like ISP with radio back hauls or small-mid FM stations). It's much more common to sight self-supported towers.

[u/TheClam-UK]

Thanks for sharing this, that was a really interesting tour.

I know in theory coax keeps all the energy inside but it still seems bizarre to me that it's safe to stand in a room with hundreds of kilowatts of RF trunked all around you in copper pipes.

[u/piquat]

I used to work as a field communications tech. Our sites were usually co-located with others on larger towers but none over about 400'. 50KW dummy load?!?! We used to run battery tests on backup battery systems that would burn through a few thousand and we'd have to open the door. Couldn't imagine 50KW. lol And I've seen impressive wave guide but that copper piping coax is insane! Wonder what that costs a foot?

Thanks.

[u/HamMcGrogu]

Monster system. Very cool to see how it all works together.

[u/KL5L]

can I get one of these in a 40m version?

[u/bilgetea]

Thanks for posting, that was fascinating!

[u/goots]

Coming from the perspective of a former combat engineer and homeland security guy, that's one heck of a vulnerable target. I didn't realize how thin those things are at the base.