I actually don't understand how/why you can hear anything, at least anything that isn't an incomprehensible mess. Isn't the signal an AM signal, essentially at the 1.12 MHz carrier frequency? How does the signal get mechanically rectified/demodulated back into the audio range? Any radio engineers out there who can explain this?
@@DanTDMJace My point is the AM signal is too high in frequency to be audible. It needs to be demodulated first to bring it into the audio range. I'm wondering what makes that happen, and how.
I'm a radio amateur (KA3KAS), and for me this was the equivalent of a Cessna private pilot getting a tour of a 747. All the principles are the same, but the scale is several orders of magnitude larger. I'd be interested in how they calculated for optimal standing wave ratio (SWR) before building it. Hearing echoes of the broadcast through all that metal is spooky indeed! Your father is a very clear presenter.
Hi, G1ZQC here in the U.K. I have played with 160m AM and tuned 1/2 waves versus grounplaned 1/4 wave aerials. Getting the optimal modulation in the AM envelope is an art, requiring a good ear whilst monitoring. All good educational fun.
Back in the day when I was doing this, broadcast stations tuned the antenna equipment using an RF bridge. Now, one would use an antenna analyzer. For a non-directional station like this, you hook the RF bridge / antenna analyzer directly to the tower feed point and measure the impedance. You need to know the exact tower resistance to calculate how many amps of RF current must be fed to the tower to get the licensed power (P = I squared R). The base current ammeter in the video was showing ~27 amps. Given that the licensed power is 50,000 watts, they must have measured ~68 ohms radiation resistance with the RF bridge / antenna analyzer. (27 * 27 * 68 ~= 50,0000). I will say that sitting at the tower base with the RF bridge, plotting the Smith chart by hand, was a big project. Now I can push a button on my antenna analyzer and it will plot a Smith chart in a few seconds! Anyway, those big coils and capacitors in the "doghouse" (ATU) are part of a Pi orT matching network that converts the 50 ohm coax from the transmitter building to the impedance of the tower. When designing the ATU, one starts with the 50+j0 impedance of the feedline from the transmitter building, and calculates the component values necessary to match to the tower impedance. Usually the network is made using tapped coils and vacuum variable capacitors, so after setting the rough values to the calculated values, one connects the RF bridge / antenna analyzer to the input of the ATU, where the feedline would connect, and tweaks the values to get exactly 50+j0. The important thing is that broadcast stations put the ATU right at the tower base, not back at the transmitter, so the 50 ohm coax is well matched to the antenna and has negligible standing waves. For directional arrays, it's a lot more complicated, because the base impedance of the tower depends on the adjustment of the array. But again, there is an ATU at the tower base which matches that towers array impedance to the 50 ohm coax to minimize standing waves on the line. At the transmitter building (usually), there is a power dividing network, called a phasor, which has a 50 ohm input from the transmitter, and a separate 50 ohm output to drive the coax to each tower. The phasor divides the power according to the ratios and phases needed to generate the licensed directional pattern. Stations often have a daytime directional pattern and a nighttime pattern. At the base of each tower, they often have separate tuning networks for each pattern, and big RF contactors, just like the one which was used to ground the tower in this video, are used to switch between tuning networks. I worked at a station which was non-directional, using the center tower, in the daytime, and directional with a 3-tower array at night. At the base of the center tower, there were 2 Pi tuning networks, one for day and one for night. At 2 end towers, there was a single Pi tuning network which was always connected to the coax, but a big RF contactor switched the tower feed point from the output of the Pi network (night), or to a "detuning" network (day). The detuning network made the tower "invisible" at the station's frequency so the the end towers did not act as parasitic director elements, basically a beam, which would have generated an oblong pattern rather than the desired circular, non-directional pattern. They talked a little about this when he said they had to make the main tower "disappear" when operating on the backup tower. The last thing I'll mention is the Austin Ring transformer, which sends AC power to the tower lights without shorting out the RF. It is basically a toroidal transformer. The primary is wound directly on the core. This is the lower ring, the primary and the core. The secondary is the upper ring. It doesn't matter how much space there is between the secondary winding and the core, so long as the winding passes through the core. It is called an Austin transformer, because Austin is the name of the company who originally manufactured them. --de N3TS
Your father is a rare breed, someone who has a wealth of information in his head and is able to explain it in a way that people can understand it. Thanks for sharing these videos, subscribed & hope to see more.
Not really..its just his specialty , to him its all.easy cuz that's his life..Same as being a Dentist dentist understand everything bout teeth etc .N GENRAL Dr knows stuff bout health but got no specialty. I bet you if you were to have him diagnose electric problems in a car he be not that Good, he'd have knowledge but not like in his specialty...
same - very well done. I'm blessed because i love this subject matter so much, as well as old steam engines and water turbine (gridding them - getting them phased to match the frequency of the line they help drive is so amazing - i've put in equipment in coal/nuclear power plants and have seen them bring up a generator/turbine into phase lock - 1000 megawatt. i love this so much!)
@@itsmisterchrisThat is entirely besides the point. Someone can be smart and be a crap teacher. Someone can be a good teacher but only surface level still. I get asked a lot to explain and get told that I'm a better teacher than their middle school one was but at the same time I envy people who are this deep into the knowledge of their profession. Maybe I can get there some day
My dad lived next to a TV antenna. I said to him one day that he could probably watch TV without having it plugged in the wall socket. He said, " Son, you can colse your eyes and see the programs on the inside of your eyelids !" I loved my dad , he was the best .
I worked at an HF transmitter site when I was in the Army. We had multiple 1kW to 70kW transmitters, about 17 Rhombic antennas, backup power generation, technical control facilities, workshops, etc. Your video brought back a lot of good memories! Thanks for all the work to put this together and share it.
More! More! More! I could watch these tours endlessly. They're beyond fascinating. Kudos to you and your Dad! And agreed about the Simpson 260. At Memphis in Navy Tradevman "A" School in the mid-60's, every bench position had a 260. They're still unbeatable.
Agreed an excellent tour and so informative. His dad was a bit confused on that Simpson he pulled off the bench. That's a model 303 VTVM. Easily identified by the two rotary switches on the front and the two circular connectors for the separate AC/Ohms and DC probes. Easy mistake as both the 260 and 303 series have identical case sizes. Enjoyed the tour so much - thanks :)
Some of my most prized possessions are the Simpsons I got from my BE mentor. Same as the Bird meters. Like a master machinist handing down his calipers.
I had no idea how complicated these transmitter towers are. What a great idea for a video. Your dad is a natural in front of the camera. He knows his stuff and explains it really well.
I'm a BS Electrical Engineer and PE, and this video validates my opinion that RF power electronics is black magic and the guys that maintain it are wizards. Seriously though, very very cool stuff!
I'm a Structural Engineer and PE, and I've engineered many a guyed tower, even 1 AM tower just like that in this video. I definitely leave all the RF stuff up to the RF folks. The spec sheets and diagrams and equipment they are constantly dealing with all flies right over my head; just tell me how big it is, how much it weights, and if it has some other special requirement, and I'll handle all the seismic, wind and ice loads for you.
Given that the numnut at my local Mickie D's is making $17/hr, asking me "do you want fries with that", Mr. Geerling and the like should be making 20x that! Seriously.
Almost 50 years ago, I worked for a 3 tower AM station. Periodically I had to go out to each tower to take base-current readings. I think I remember the hair on my arms standing straight up because of all the power in the dog house. We had to take the readings when there was no modulation, so we had a little transistor radio… but it didn’t have to be set to the station frequency. It was so powerful in there, you could set it to any frequency and you’d hear it. I was just a kid of 20 with almost no training. Lucky I didn’t touch anything that would have killed me.
An electrician at my work said when he was starting out he worked at an old coal preparation plant and said their electrician sent him into the control room where all the panels and electrical buses were located and he said as soon as he walked in the hairs stood up on end and the further he went in he started feeling like he was being stung by a bee. Those old transistors, inverters and relays were electrifying the air. Thankfully with todays solid state drives and better insulation I don’t have to deal that in my coal plant’s control room
As a retired design engineer who worked predominantly with digital circuits, I always looked on RF as a bit of a black-art. What this has shown me is that high-power RF is in a league of its own. I loved that modular high-efficiency AM transmitter cabinet - I had no idea it was done like that these days. All the shiny copper was nice too. The whole video was truly fascinating. Thank you. both, for taking the time and sharing this knowledge.
My first job out of college was fixing 300watt 1GHz-ish cell tower radios. Definitely higher power compared to consumer or even enthusiast grade, but absolutely nothing compared to this stuff. But the FPGAs everywhere? That was remarkably consistent. Got some extra board space? Slap an extra FPGA in there and let's get some more monitoring and control capability. The prototypes were even crazier, FPGAs the size of a credit card.
Honestly it's kinda fascinating that AM even still exists in 2024. You'd think that with the advent of FM and then digital, that AM would have been phased out decades ago.
Love these episodes with your dad nerding away like crazy.. 😂 Please keep on making them. Awesome to listen to the incredible knowledge and how he breathes RF!
Thanks for sharing. My dad (he’s just turned 99!) had an older friend who was a radio engineer. Always interesting, and always ready to share his love of science and technology with anyone who wanted to learn. Your dad reminds me of him.
Your dad seems like a cool guy, you're so lucky you can still have that experience with your pops. Don't take it for granted. Great video too, love the transmitter sites. I once worked at place that had satellite transmitters and some things are similar.
It's good to see things like this, which I was used to seeing when I accompanied my father, working for Portuguese Broadcasting. It was and continues to be a very special world. Thank you for making these images available and thank you also for the comments throughout the video, absolutely crucial for anyone interested in this technical area. Stay safe! Macedo Pinto, Portugal
I've been an AM radio DX'er for years. When I was younger, KMOX was the first DX I ever picked up back in the early 90's, on my little GPX stereo. I've been hooked ever since. Now I have radios galore and 25 years worth of good DX contacts. I live up in Wisconsin, just north of Chicago. Late at night, 1-2AM, I can pick up NYC, and Los Angeles, Dallas, Denver, Winnipeg, Toronto, Montreal, Nashville. Basically if the conditions are good, I can pick up almost the entire US. Getting anything from west of the rockies is difficult though
1130AM KWKH, a local 50K station, was able to be heard all over the country back in the day. They had the Louisiana Hayride where Elvis debuted as well as countless other stars. You know that saying "ELVIS HAS LEFT THE BUILDING!"? The first time it was said was here at the Hayride. All the fans were staying there, waiting on Elvis to come back out so they finally had to tell the fans Elvis was gone so they'd leave! 🤣
KMOX was my first-ever AM DX station as well. I was about 5 or 6 years old in suburban Montreal, Canada, listening under the covers on a really good transistor radio. My teachers in grade school were amazed how I knew what the weather was in St. Louis, that there were tornados overnight, and similar tidbits of knowledge from the eastern half of the US, as I listened to WWRL, WSB, KDKA, and the rest of the 50kW blowtorches.
This brought back memories, my Grandfather was a radio engineer and ran the tower at KOKH 25 UHF when I was a kid. He used to let me push the button that signed the station on and off. Excellent video. Got me into working to get my amateur radio license, just like he had. ( W5JYT) Very informative and comprehensive video. Please do more!
My dad worked for two-way radio, zipcall, metromedia paging in the Boston area. When I was younger in the 60s I would go with him on many of his service calls. This video brings back many good memories during that time period. One of his contracts was with WBZ TV, but he also serviced the US Navy, the Coast Guard (Nantucket Light), Woods Hole, etc. He had a fascinating life, and always had great stories. I remember him telling me that he had to service a transmitter on Mt. Wachusett. He didn't know at the time the transmitter tower itself was live. He grabbed the tower and was thrown back. One of the guys he worked with laughed and told him he had to jump onto the tower in order to climb it. At another time the Navy sent him out to service the radio equipment on a tugboat. When he got to the boat location, he called and told the Navy that he couldn't service the boat. When asked why, he said the boat had sunk at the dock. They had to raise the boat before he could service the equipment. He was literally in love with his job. Miss you dad. RIP. ❤
Nice tour! Re the Xilinx chips: I designed hardware at Nautel for a while, and we used FPGAs in all sorts of places on both the AM and FM product lines. We didn't use them because of a lack of volume to justify rolling an ASIC, we used them because they kick ass. FPGAs are absolute monsters at doing real-time DSP calculations, which is what you need for modern radio broadcast transmitter technology, especially since HD Radio came on the scene. Modern FPGA chips have hundreds, even thousands of DSP slices with tightly coupled memory which can run at hundreds of MHz. Comparing a classic DSP chip to a FPGA is like comparing a CPU to a GPU - the latter is a lot harder to program for and not suitable for a lot of tasks, but for certain tasks can absolutely mop the floor with the former. In the exciter board in our FM transmitters, the main DSP chip sends a digital baseband over to the FPGA at a couple megasamples/sec - the FPGA then upsamples this to a much higher processing rate, applies a bunch of voodoo to linearize and improve the energy efficiency of the transmitter, frequency shifts the baseband with a DDS to set the transmit frequency, and outputs the resulting high speed data stream to a high speed RF DAC that generates the main RF signal for the transmitter. Simultaneously, the same FPGA captures samples from a high speed ADC which is sniffing the RF output of the transmitter, this gets used for the adaptive linearization voodoo and a few other things. In terms of raw calculations, the FPGA ends up doing easily 1000x the amount of DSP calculations that the actual DSP chip on the board does.
Hi, can you share which programming languages did you use to run FM multiplex to RF pipeline inside the exciter? I understand there had to be either Verilog or VHDL for FPGA I wonder what was used for microcontrollers running the whole thing. Which language the predistortion engine is written?
This video was recommended. I originally thought I would watch a few minutes and move on, BUT I really really enjoyed the video. Yall kept it interesting and humorous. Thank you for the inside view of KMOX and your history. Why does every business have a space where chairs go to die but never quite make it to the dumpster. Subbed and thumbed.
I wonder if every current KMOX employee got one chair each. Would there still be pile of chairs? LOL Have a great day. Do not touch the tower..@@GeerlingEngineering
I've listened to KMOX since the early 70's. Strongest distant station (about 35-40 miles) I can get. We have a local station, but its only about 10 miles away.
I am a contract broadcast engineer and know all this but somehow watch the whole video because it's really cool to see how other guys do the same things.
I love this. I've had a Simpson 260 for some 60+ years and I don't think I could live without it. Even with modern stuff that costs a bundle, the 260 is really the most valuable piece of test equipment I've ever had. A little plus is the mirrored scale, which for us old old old timers helps us with our eyesight.
I always found interesting how as you increase frequency, the electricity goes from travelling in wires to travelling in pipes, and then as you increase even more into UHF and microwave it starts looking like HVAC ducts.
The algorithm was trying to get me to watch this all week. I finally relented and I'm now hitting myself for not doing it earlier. Your dad is incredible at explaining this stuff, and his enthusiasm is contagious. I'm a software guy who can read schematics and do some soldering and this RF stuff is half black magic and half "I bet it works if you don't think about it too hard". I didn't know AM modulation wasn't just effectively talking into a 50,000 watt amplifier and connecting an antenna instead of a speaker any more (talking specifically about those modulators at 28:16). It amazes me after seeing all of this that they were able to stand up stations 100+ years ago, let alone monuments to brute force like WLW-AM at 500 kW in the 1930s.
I always remember listening to the Blues and Cards driving home at night as a storm was approaching. You could always tell when it was getting near by how loud and frequent the crackles in the signal were!
Thanks for the tour. Just imagine putting that lot at 50kw and more, on board a Ship. As was done in the 60s and 70s on the Radio Ships that served AM to the U.K. and the continent of Europe. Radio Caroline, Radio North sea International, Radio City, Radio London. The true pioneers of UK local radio. Radio Caroline still exist today, but licenced on land 4KW on 648kHz at Orford Ness in the South East of England. They run the transmitter on Solar power during the daylight. Look them up, well worth a visit, and they still have the last Radio Ship, fully kitted out, but connected to the TX site via the internet. Yes they still broadcast from the Ship once a month.
These tours with your dad are great! Very cool to see these sites and the changes that have occurred over the years. Many of us hams get excited about our 100W transceivers and maybe a 1500W amp but these stations are the real deal. Keep up the good work!
I get nervous with my little 5W transceiver haha My Dad's used to high power... I just remember how much a little 120v shock hurt, and my Dad described RF burns and made me want to give anything in a transmission line a wide berth.
When growing up in Florissant, my Grandfather would have his little portable radio playing KMOX with him either in the house, out working in his workshop, or just siting out on the front porch. On a clear night I can get KMOX 800 miles away in Charlotte, NC.
This takes me back to my teenage years. One of my scout leaders growing up was a broadcast engineer (Pete at MidAmerica. Your father will know him, I'm sure.) I worked for him a little after high school and we went to a bunch of xmitter sites. He sounds very similar to your dad. I watched him wind coils, service xmitters, all sorts of stuff. Later, I worked with him on my master's thesis of automating the measurement of AM tower patterns. good times.
Fantastic video. As a ham radio guy who's also been listening to KMOX since I was very young, this was a very interesting video! It's really neat to see all the infrastructure required to provide the wide coverage area and quality audio of KMOX.
I am an Amateur Radio Op as well (W4KDN) and was privileged to experience a VIP tour of the Trans World Radio site on the island of Bonaire (about 50 miles off the coast of Venezuela). TWR runs 440 KW into a 4 tower directional and steerable array. I authored an article and submitted it to QST which was published. This video brought back some not too distant memories of that tour.
I had a hole blasted in my thumb through a glove from a 1kw transmitter, the owner shut the tower down (so he thought, got sidetracked by our conversation). When I got outside to the tower I thought I could still "feel" the energy, and instead of walking 200 ft back to the headend or walking the same distance to the truck for the voltage indicator, just to make sure (With my gear on in 100deg heat after all I saw him open the panel on the transmitter where the breaker is) I decided to skim the ring with my thumb.. not smart.
As a radio/Ham enthusiast I enjoy seeing the big boy setups like this. Pretty cool that ATU is the size of a small building. It was interesting to see that transformer ring for the light power. Very cool stuff. Thanks for including the radials this time. Awesome video.
Extremely interesting. Always wanted to see the interior of the huts and buildings at radio transmitter stations. Good program. Well recorded and produced.
My father was a ham operator for all of his life, so watching this video was super nostalgic for me. Absolutely love the amount of information in this video!
Well done! Thanks for the in-depth tour. 10/10 and very interesting. Seeing this made me feel a twinge of pride, as KMOX is the AM powerhouse in my region. Soak up all the knowledge you can from your Dad, and men like him, he's a real jewel.
Man I love this video 10/10. It was so informative. I learned so much about am radio towers. All I knew before was they were energized and the wavelengths were impractically huge. I chuckled at 950mhz studio link antenna called microwave rather than UHF. Its right but its just so strange as someone who worked with 900mhz to 60ghz. We just called everything sub 1ghz UHF.
@@GeerlingEngineering So true. For other viewers here's some comparisons in the wavelength size. 49965.4096666667km wavelength @ 6hz (Teslas wireless power system) 555 meters wavelength @ 0.540mhz (start of AM broadcast band) 176 meters @ 1.7mhz (end of AM broadcast band) 11 meters @ 27mhz (CB radio) 5.99 meters @ 50mhz (6 meter ham band) 2.8 meters @ 107mhz (end of FM band) 2 meters @ 147mhz (2 meter ham band) 68cm @ 440mhz (UHF ham band) 54cm @ 550mhz (best UHF television band) 42cm @ 700mhz (cellular 700mhz band) 32cm @915mhz (ism 900mhz uhf band) 12cm @2412mhz ( wifi) 8cm @ 3.655ghz (Wireless Broadband Services WBS band for licensed fixed wireless) 5cm @ 5830mhz (end of 5ghz uni3 wifi) 1.2cm @ 24ghz (unlicensed 24ghz band) 4mm @ 60ghz (unlicensed 60ghz band) 3mm @ 90ghz (upper band mmwave 5g) 0.9mm @ 300ghz (right before it becomes infrared) Its truly an amazing thing that people were ever able to figure out that radio waves, heat and light were the same thing before microwave spectrum and radar was a thing.
Do you mean AM (amplitude modulation), or Medium Wave (0.5 to 1.5 mhz)? We use the terms interchangeably for broadcast radio, but they each speak to different things. For example, the entire mast being the antenna is because it's medium wave, and would apply regardless of the modulation. Meanwhile hearing echoes of the transmission are because it's AM, and would happen regardless of the frequency. I guess my point is that I wish the video made these differences a little more explicit.
Wow! I lived in St. Louis in the ‘90s for 5 years and listened to KMOX. I moved to Peoria, IL, and went to work for ROHN designing antenna towers. One of the differences is I spotted is that we would design provide a 3’ high base pedistal which is higher than KMOX’s. The reason was to keep the weeds from touching the base insulator and reduce the varmits from getting on the tower and causing an outage. I recognized a lot of the tower and, guy hardware and lights we would sell. In another life I was in the electrical world and delt with varmit control in electrical substations. I had to stop squirrels from climbing on the circuit breakers and cutting power to the Texas Medical Center. I designed a squirrel proof fence. Today they have electric barriers in their substations to keep the varmits off the high voltage equipment. I totally enjoyed the video because I have never had the cooks tour of an AM radio station, much less than one I used to listen to.
I saw one of those Buss Fuses displays at, coincidentally, the bus workshop my dad worked at. So when I was a little kid I thought that meant the fuses were designed for busses. And since cars are smaller than buses, using a buss fuse on a car would give it extra reliability.
Your dad’s expression in the thumbnail is fantastic! 😂 Love the content with your dad, I’ve always been curious how broadcast stations work - I’m a ham and had a college radio show for a while.
My dad works in radio, and i used to walk up to the AM towers. Beautiful sight. Never touched them, glad I didn't. Fantastic video, highly informative! down to earth.
A late friend of mine was station engineer of AM station WEMP & what he told me of operation of a am radio station is exactly how you describe it. Thanks for posting this very informative video.
Have you ever visited the Voice of America Museum in West Chester, Ohio? They still have a 250,000 watt transmitter (un powered), and a lot of high power radio stuff. And down the street is an original Blaw Knox antenna (WLW-AM).
I love these tours. Currently a technician working on various FAA equipment kind of near St. Louis. It’s always so cool to see the kind of radio equipment that I work on, but on steroids! Please keep the coming!
@@duck_rifle5879 they only post them once or twice a year. A lot of times to their based on FAA needs when it comes to location. They like to have people with backgrounds in electronics, radios, etc which a lot of people get from the military. 2101 ATSS is the job title if you want to look it up
I always love everything radio and broadcast related, it is super interesting to see, keep the videos coming! It is such an interesting industry, I am really glad to work at a broadcast equipment manufacturer.
Felt guilty because I listened to KSHE when living in St Louis during the 70's but I sure remember KMOX powerhouse. Wow. Thanks. What a treat for an ole broadcast Engineer and a High Schooler from UCity. Thanks again for all your efforts. Scott
I was a radio operator in the military '85-'95. Radio/Radioteletype SSB AM. We used a 15' whip antenna (xmitting about 10k volts RF) on the vehicle for mobile use, but when we set up we raised a 50 ohm doublet (cut to whatever freq we were assigned). While deployed during the first Gulf war, we had to set up during a sandstorm. Once the antenna was raised, I picked up the end of the coax nearest the truck to connect it. Big mistake. The static that had built up from the blowing sand was enough to knock the ever-lovin fool outta me. My whole body jolted and it felt like someone smacked the bottom of my heels with a sledgehammer. The connector literally arced to the grounded equipment when we went to connect it.
Man, ive been a fan of you for a little over a year or two Jeff, but i have loved radio and radio technology for years. This stuff is teaching me so much (im trying to get my amateur license for the first time) and its very interesting. Thanks for all of the hard work you put into your content. Also, hope youre doing well with your Chrons. I know that can be debilitating as all hell.
I was the AM transmitter RFTech for WJJZ 1460 Kc. It was my job to monitor the Dog House on an island in the Delaware River. I worked alone 3 Fay’s a week Friday to Sunday 12 hour days. Ours was a 5 kilowatt station. I arouse at four AM and drove to the Marina, then took an outboard motor boat around the cove to our landing. It was a lonely boring job requiring an FCC 1st Class Radiotelephone license. The hourly pay was good, but no benefits or vacation. I left that job for a much better gig with RCA building in the space program. They asked me to change the lights on top of the antenna in the dark. I refused, I was fired! It was always my goal to work in broadcasting , radio and or TV. This job cured me fast!
Absolutely love this video. I've been doing this kind of broadcast work for 37 years. With most forms of entertainment moving to The Internet, Guys like us are a dying breed. Treat your Broadcast Engineer well. 😁
Those porcelain insulators are marvels. the little single "petticoats" used for suspending the lowest of the high voltage distribution outside most homes are rated something like 10-30klb tension or compression. That large one is probably rated 100klb.
@@zoopercoolguy I was a field communications tech. Started out climbing towers but ones less than about 300'. Even those... well there's a LOT of weight there, then the guys and the tension, it's crazy that's all sitting on a hollow ceramic tube. It's crazy enough that they usually kind of come to a point on the bottom to pivot, but that's steel. This is nuts to me and I've been around the "smaller" versions of this stuff.
Did a TV transmitter site a few years back from the demo of 3 old analog transmitters and associated matching wave guides and coax to the power to the new dishes out in the field. From the ground up it was allot of work. The grounding of the transmitter was all that and then some! Transmitters and dummy load were all water cooled as well so there was multiple pumps and CAN bus for control and monitor. ERP on the UHF band was about double this site in the video. Fun job being there on the first day of operation and switching over from the previous transmitter site.
7:22 austin ring transformer Aren t there many magnetic losses in that open air transformer wouldn t you lose half of the power before energizing the antenna? a radio amateur asking
I am looking into a startup online radio station and it will be all vinyl LP. mastered, with true Full Length Stereo(FLS). the seperation heard will be way better than any station up and running as of today! Mono, will be heard on one speaker as Mono is a one channel mix, not two!
Back in 1986, my landlord in Germany arranged a tour of Radio Luxembourg's 1,200,000 watt daytime, and 600,000 watt nighttime AM transmitters, located in Marnach, and broadcasting on 1400(1439) kHz. There were three towers phased to allow a north/south radiation pattern which blasted the British Isles. Can you imagine a transmitter with 24 times KMOX's 50,000 watt power!
Thank you for the Contant and remind me of the days when I used to play around in college with RF I really loved it. It was my passion, but I did not follow through with it but I am into telecommunications engineering now, but it would’ve been fun to work at a RF tower.
Geerling Engineering is like the Engineering Explained of RF and radio infrastructure, and I love it! Edit: I laughed a bit at the batteries being on wooden boards at 16:33, reminds me of the superstitions my grandfather tolk me about concrete discharging lead acids lol.
Nice, detailed look at the doghouse. Well done. I've been a ham operator, an FCC broadcast licensee and a communications tech for over 55 years. Went inside a Navy VLF site once and it's all the same whether VLF or UHF just larger or smaller components. Microwave component construction gets a bit different, but the principles are all still the same.
really glad i found this channel. relatively new (4 years in) to IT tech, and this stuff is super interesting to watch, especially the second half of the video. this guy is really an all around master at his craft, he knows the entire site inside and out. pretty cool
A splice like what your dad showed is usually the strongest way to terminate cables/ropes, it takes a lot of time to do properly but it can even be stronger than the cable would be by itself. Most ski lifts/gondolas use some variation of that.
I can here KMOX in the evenings and overnight from Winnipeg, Manitoba , Canada.1000 miles north. I first got into AM dx in the 80's and I remember tuning in KMOX with my clock radio!
As someone who ran a highly available data center I love how much crossover there is with this radio site! I wonder if they have as many problems with wear on the ATS contacts as we did, had to have the contacts replaced twice in 8 years.
They did seem to have issues on certain switches-from my conversation with my Dad (some was cut for time, on this long video), they had to maintain the transfer switches more than any other part of the power delivery chain.
Impressive how Dad explained things so well without much technical language. I’m sure he knows the technical aspects - in depth - and for him there’s no magic at all.
KMOX, was one of the first stations I DX'ed back in 1960, when I starting listening to MW from the NY city area. It was an RCA portable with mini tubes and an old type battery. Some years ago, my wife and I had friends in Dorsey, IL. not too far from KMOX site. 😊
Your dad looks 100% modern American institutional engineer. I love it! I grew up with these guys at Northrop Grumman, Rockwell, and Boeing and they all wear the same collared shirts and khakis! Lolol. God bless this man for agreeing to do this tour… he has a great personality and ability to make the complex seem more simple! Great editing too.
I really like how when I just listen to the audio you two sounds so alike it almost sounds like it's the same person sometimes. Or like there's an older and younger version of the same guy having a conversation
Thanks for the tour of the station, I work around that kind of stuff myself and was laughing at some of the same things I see stored at almost all broadcast facilities. Very well done.
The fact that you can hear the radio station inside the building just based on how much energy is radiating off conductors is absolutely terrifying.
I actually don't understand how/why you can hear anything, at least anything that isn't an incomprehensible mess. Isn't the signal an AM signal, essentially at the 1.12 MHz carrier frequency? How does the signal get mechanically rectified/demodulated back into the audio range? Any radio engineers out there who can explain this?
@@PukkehFrom what I understand, that building is what makes the AM signal. I'm probably wrong.
@@DanTDMJace My point is the AM signal is too high in frequency to be audible. It needs to be demodulated first to bring it into the audio range. I'm wondering what makes that happen, and how.
@@Pukkehair is a kinda shitty medium so maybe something with that, or maybe it’s magnetic fields causing resonance
Yea this is fascinating and I need to know how this works!
I'm a radio amateur (KA3KAS), and for me this was the equivalent of a Cessna private pilot getting a tour of a 747. All the principles are the same, but the scale is several orders of magnitude larger. I'd be interested in how they calculated for optimal standing wave ratio (SWR) before building it. Hearing echoes of the broadcast through all that metal is spooky indeed! Your father is a very clear presenter.
I agree!!!
Hi, G1ZQC here in the U.K. I have played with 160m AM and tuned 1/2 waves versus grounplaned 1/4 wave aerials. Getting the optimal modulation in the AM envelope is an art, requiring a good ear whilst monitoring. All good educational fun.
73rd like 😎
So that's the weird background robotic-ish sounds we hear, that you call Broadcast Echos?
Back in the day when I was doing this, broadcast stations tuned the antenna equipment using an RF bridge. Now, one would use an antenna analyzer. For a non-directional station like this, you hook the RF bridge / antenna analyzer directly to the tower feed point and measure the impedance. You need to know the exact tower resistance to calculate how many amps of RF current must be fed to the tower to get the licensed power (P = I squared R). The base current ammeter in the video was showing ~27 amps. Given that the licensed power is 50,000 watts, they must have measured ~68 ohms radiation resistance with the RF bridge / antenna analyzer. (27 * 27 * 68 ~= 50,0000). I will say that sitting at the tower base with the RF bridge, plotting the Smith chart by hand, was a big project. Now I can push a button on my antenna analyzer and it will plot a Smith chart in a few seconds!
Anyway, those big coils and capacitors in the "doghouse" (ATU) are part of a Pi orT matching network that converts the 50 ohm coax from the transmitter building to the impedance of the tower. When designing the ATU, one starts with the 50+j0 impedance of the feedline from the transmitter building, and calculates the component values necessary to match to the tower impedance. Usually the network is made using tapped coils and vacuum variable capacitors, so after setting the rough values to the calculated values, one connects the RF bridge / antenna analyzer to the input of the ATU, where the feedline would connect, and tweaks the values to get exactly 50+j0.
The important thing is that broadcast stations put the ATU right at the tower base, not back at the transmitter, so the 50 ohm coax is well matched to the antenna and has negligible standing waves.
For directional arrays, it's a lot more complicated, because the base impedance of the tower depends on the adjustment of the array. But again, there is an ATU at the tower base which matches that towers array impedance to the 50 ohm coax to minimize standing waves on the line. At the transmitter building (usually), there is a power dividing network, called a phasor, which has a 50 ohm input from the transmitter, and a separate 50 ohm output to drive the coax to each tower. The phasor divides the power according to the ratios and phases needed to generate the licensed directional pattern.
Stations often have a daytime directional pattern and a nighttime pattern. At the base of each tower, they often have separate tuning networks for each pattern, and big RF contactors, just like the one which was used to ground the tower in this video, are used to switch between tuning networks. I worked at a station which was non-directional, using the center tower, in the daytime, and directional with a 3-tower array at night. At the base of the center tower, there were 2 Pi tuning networks, one for day and one for night. At 2 end towers, there was a single Pi tuning network which was always connected to the coax, but a big RF contactor switched the tower feed point from the output of the Pi network (night), or to a "detuning" network (day). The detuning network made the tower "invisible" at the station's frequency so the the end towers did not act as parasitic director elements, basically a beam, which would have generated an oblong pattern rather than the desired circular, non-directional pattern. They talked a little about this when he said they had to make the main tower "disappear" when operating on the backup tower.
The last thing I'll mention is the Austin Ring transformer, which sends AC power to the tower lights without shorting out the RF. It is basically a toroidal transformer. The primary is wound directly on the core. This is the lower ring, the primary and the core. The secondary is the upper ring. It doesn't matter how much space there is between the secondary winding and the core, so long as the winding passes through the core. It is called an Austin transformer, because Austin is the name of the company who originally manufactured them.
--de N3TS
Your father is a rare breed, someone who has a wealth of information in his head and is able to explain it in a way that people can understand it. Thanks for sharing these videos, subscribed & hope to see more.
Not really..its just his specialty , to him its all.easy cuz that's his life..Same as being a Dentist dentist understand everything bout teeth etc .N GENRAL Dr knows stuff bout health but got no specialty. I bet you if you were to have him diagnose electric problems in a car he be not that Good, he'd have knowledge but not like in his specialty...
“If you can’t explain it to a six-year-old, then you don’t understand it yourself” - Albert Einstein
same - very well done. I'm blessed because i love this subject matter so much, as well as old steam engines and water turbine (gridding them - getting them phased to match the frequency of the line they help drive is so amazing - i've put in equipment in coal/nuclear power plants and have seen them bring up a generator/turbine into phase lock - 1000 megawatt. i love this so much!)
@@itsmisterchrisThat is entirely besides the point. Someone can be smart and be a crap teacher. Someone can be a good teacher but only surface level still. I get asked a lot to explain and get told that I'm a better teacher than their middle school one was but at the same time I envy people who are this deep into the knowledge of their profession. Maybe I can get there some day
Very very intelligent man
My dad lived next to a TV antenna. I said to him one day that he could probably watch TV without having it plugged in the wall socket. He said, " Son, you can colse your eyes and see the programs on the inside of your eyelids !"
I loved my dad , he was the best .
I bet he had excellent reception!
@@chrisvaughn5960
Cristal clear 👌
ya the sicko devil minions demonology
I worked at an HF transmitter site when I was in the Army. We had multiple 1kW to 70kW transmitters, about 17 Rhombic antennas, backup power generation, technical control facilities, workshops, etc. Your video brought back a lot of good memories! Thanks for all the work to put this together and share it.
More! More! More! I could watch these tours endlessly. They're beyond fascinating. Kudos to you and your Dad! And agreed about the Simpson 260. At Memphis in Navy Tradevman "A" School in the mid-60's, every bench position had a 260. They're still unbeatable.
They have been around a long time!!!
Although mine lost the battle raising 4 kids! But a few drops were my fault…
Agreed an excellent tour and so informative. His dad was a bit confused on that Simpson he pulled off the bench. That's a model 303 VTVM. Easily identified by the two rotary switches on the front and the two circular connectors for the separate AC/Ohms and DC probes. Easy mistake as both the 260 and 303 series have identical case sizes. Enjoyed the tour so much - thanks :)
Bet he's also got a Weller 8200!!!!
Some of my most prized possessions are the Simpsons I got from my BE mentor. Same as the Bird meters. Like a master machinist handing down his calipers.
I had no idea how complicated these transmitter towers are. What a great idea for a video. Your dad is a natural in front of the camera. He knows his stuff and explains it really well.
I'm a BS Electrical Engineer and PE, and this video validates my opinion that RF power electronics is black magic and the guys that maintain it are wizards.
Seriously though, very very cool stuff!
Agreed 🧙♂️
.... Yeah, what he said.... RF is Voodoo and the people good at it are wizards.
I'm a Structural Engineer and PE, and I've engineered many a guyed tower, even 1 AM tower just like that in this video. I definitely leave all the RF stuff up to the RF folks. The spec sheets and diagrams and equipment they are constantly dealing with all flies right over my head; just tell me how big it is, how much it weights, and if it has some other special requirement, and I'll handle all the seismic, wind and ice loads for you.
Given that the numnut at my local Mickie D's is making $17/hr, asking me "do you want fries with that", Mr. Geerling and the like should be making 20x that! Seriously.
@@markb978idiot
Almost 50 years ago, I worked for a 3 tower AM station. Periodically I had to go out to each tower to take base-current readings. I think I remember the hair on my arms standing straight up because of all the power in the dog house. We had to take the readings when there was no modulation, so we had a little transistor radio… but it didn’t have to be set to the station frequency. It was so powerful in there, you could set it to any frequency and you’d hear it. I was just a kid of 20 with almost no training. Lucky I didn’t touch anything that would have killed me.
An electrician at my work said when he was starting out he worked at an old coal preparation plant and said their electrician sent him into the control room where all the panels and electrical buses were located and he said as soon as he walked in the hairs stood up on end and the further he went in he started feeling like he was being stung by a bee. Those old transistors, inverters and relays were electrifying the air. Thankfully with todays solid state drives and better insulation I don’t have to deal that in my coal plant’s control room
As a retired design engineer who worked predominantly with digital circuits, I always looked on RF as a bit of a black-art. What this has shown me is that high-power RF is in a league of its own. I loved that modular high-efficiency AM transmitter cabinet - I had no idea it was done like that these days. All the shiny copper was nice too. The whole video was truly fascinating. Thank you. both, for taking the time and sharing this knowledge.
Wow
My first job out of college was fixing 300watt 1GHz-ish cell tower radios. Definitely higher power compared to consumer or even enthusiast grade, but absolutely nothing compared to this stuff.
But the FPGAs everywhere? That was remarkably consistent. Got some extra board space? Slap an extra FPGA in there and let's get some more monitoring and control capability. The prototypes were even crazier, FPGAs the size of a credit card.
Honestly it's kinda fascinating that AM even still exists in 2024. You'd think that with the advent of FM and then digital, that AM would have been phased out decades ago.
Please don't touch the tower. I actually like your content.
Darwin’s theory of natural selection.
Touch my monkey
It would only hurt for a little while but the smell would be horrific.
imagine touching the tower and getting never gunna give you up played by your skin as it burns
I'd lick it
Love these episodes with your dad nerding away like crazy.. 😂 Please keep on making them. Awesome to listen to the incredible knowledge and how he breathes RF!
literal porn.
I’m seconding this. I love these episodes.
Thanks for sharing. My dad (he’s just turned 99!) had an older friend who was a radio engineer. Always interesting, and always ready to share his love of science and technology with anyone who wanted to learn. Your dad reminds me of him.
Your dad seems like a cool guy, you're so lucky you can still have that experience with your pops. Don't take it for granted. Great video too, love the transmitter sites. I once worked at place that had satellite transmitters and some things are similar.
My brother knew a guy who died exactly that way! Pointing up as a joke while taking an electrical engineering student tour. Done!
i feel bad for him but at the same time, those people are why we cant do anything cool anymore
It's good to see things like this, which I was used to seeing when I accompanied my father, working for Portuguese Broadcasting. It was and continues to be a very special world. Thank you for making these images available and thank you also for the comments throughout the video, absolutely crucial for anyone interested in this technical area.
Stay safe!
Macedo Pinto, Portugal
I've been an AM radio DX'er for years. When I was younger, KMOX was the first DX I ever picked up back in the early 90's, on my little GPX stereo. I've been hooked ever since. Now I have radios galore and 25 years worth of good DX contacts. I live up in Wisconsin, just north of Chicago. Late at night, 1-2AM, I can pick up NYC, and Los Angeles, Dallas, Denver, Winnipeg, Toronto, Montreal, Nashville. Basically if the conditions are good, I can pick up almost the entire US. Getting anything from west of the rockies is difficult though
Pesky mountains!
Here in Michigan KMOX sounds like a local after sunset most of the time. Love those clear channel 50K stations!!!!
1130AM KWKH, a local 50K station, was able to be heard all over the country back in the day. They had the Louisiana Hayride where Elvis debuted as well as countless other stars. You know that saying "ELVIS HAS LEFT THE BUILDING!"? The first time it was said was here at the Hayride. All the fans were staying there, waiting on Elvis to come back out so they finally had to tell the fans Elvis was gone so they'd leave! 🤣
Hey neighbor LOL... Mike M Wausau / Merrill Area....
KMOX was my first-ever AM DX station as well. I was about 5 or 6 years old in suburban Montreal, Canada, listening under the covers on a really good transistor radio. My teachers in grade school were amazed how I knew what the weather was in St. Louis, that there were tornados overnight, and similar tidbits of knowledge from the eastern half of the US, as I listened to WWRL, WSB, KDKA, and the rest of the 50kW blowtorches.
Your dad’s knowledge is amazing! As an amateur radio operator being able to see this is incredibly fascinating! Thank you so much for sharing!
This brought back memories, my Grandfather was a radio engineer and ran the tower at KOKH 25 UHF when I was a kid. He used to let me push the button that signed the station on and off. Excellent video. Got me into working to get my amateur radio license, just like he had. ( W5JYT) Very informative and comprehensive video. Please do more!
My dad worked for two-way radio, zipcall, metromedia paging in the Boston area. When I was younger in the 60s I would go with him on many of his service calls. This video brings back many good memories during that time period. One of his contracts was with WBZ TV, but he also serviced the US Navy, the Coast Guard (Nantucket Light), Woods Hole, etc. He had a fascinating life, and always had great stories.
I remember him telling me that he had to service a transmitter on Mt. Wachusett. He didn't know at the time the transmitter tower itself was live. He grabbed the tower and was thrown back. One of the guys he worked with laughed and told him he had to jump onto the tower in order to climb it.
At another time the Navy sent him out to service the radio equipment on a tugboat. When he got to the boat location, he called and told the Navy that he couldn't service the boat. When asked why, he said the boat had sunk at the dock. They had to raise the boat before he could service the equipment.
He was literally in love with his job. Miss you dad. RIP. ❤
A big thank you to your dad and you for recording this, it was super interesting!
Nice tour!
Re the Xilinx chips: I designed hardware at Nautel for a while, and we used FPGAs in all sorts of places on both the AM and FM product lines. We didn't use them because of a lack of volume to justify rolling an ASIC, we used them because they kick ass.
FPGAs are absolute monsters at doing real-time DSP calculations, which is what you need for modern radio broadcast transmitter technology, especially since HD Radio came on the scene. Modern FPGA chips have hundreds, even thousands of DSP slices with tightly coupled memory which can run at hundreds of MHz. Comparing a classic DSP chip to a FPGA is like comparing a CPU to a GPU - the latter is a lot harder to program for and not suitable for a lot of tasks, but for certain tasks can absolutely mop the floor with the former.
In the exciter board in our FM transmitters, the main DSP chip sends a digital baseband over to the FPGA at a couple megasamples/sec - the FPGA then upsamples this to a much higher processing rate, applies a bunch of voodoo to linearize and improve the energy efficiency of the transmitter, frequency shifts the baseband with a DDS to set the transmit frequency, and outputs the resulting high speed data stream to a high speed RF DAC that generates the main RF signal for the transmitter. Simultaneously, the same FPGA captures samples from a high speed ADC which is sniffing the RF output of the transmitter, this gets used for the adaptive linearization voodoo and a few other things.
In terms of raw calculations, the FPGA ends up doing easily 1000x the amount of DSP calculations that the actual DSP chip on the board does.
Now... I want to go to Gates or some other manufacturer and talk to their engineers. Fascinating!
I've got contacts at Nautel, and Elenos/BE to a lesser extent, and might be able to arrange something.
Hi, can you share which programming languages did you use to run FM multiplex to RF pipeline inside the exciter? I understand there had to be either Verilog or VHDL for FPGA I wonder what was used for microcontrollers running the whole thing. Which language the predistortion engine is written?
@@antronx7 I can't share that information.
@@garymarsh23well you could, but then you’d have to kill him ….😉
This video was recommended. I originally thought I would watch a few minutes and move on, BUT I really really enjoyed the video. Yall kept it interesting and humorous. Thank you for the inside view of KMOX and your history. Why does every business have a space where chairs go to die but never quite make it to the dumpster. Subbed and thumbed.
Haha I know what you mean. I think every business with more than a few employees ends up with one of those chair graveyards!
I wonder if every current KMOX employee got one chair each. Would there still be pile of chairs? LOL Have a great day. Do not touch the tower..@@GeerlingEngineering
it always amazes me how far away from STL I can hear KMOX. This was super cool to see, thanks for sharing.
I've listened to KMOX since the early 70's. Strongest distant station (about 35-40 miles) I can get. We have a local station, but its only about 10 miles away.
I am a contract broadcast engineer and know all this but somehow watch the whole video because it's really cool to see how other guys do the same things.
I love this. I've had a Simpson 260 for some 60+ years and I don't think I could live without it. Even with modern stuff that costs a bundle, the 260 is really the most valuable piece of test equipment I've ever had. A little plus is the mirrored scale, which for us old old old timers helps us with our eyesight.
The Simpson 260 is a must for telephone techs. A old timer trained me on how to test the outside lines with an analog meter.
Great meter. Don't drop it on a cement floor.
Nice to see how AM radio is still very elaborately run and clearly not going anywhere anytime soon. Great content, thanks KMOX for the tour.
I always found interesting how as you increase frequency, the electricity goes from travelling in wires to travelling in pipes, and then as you increase even more into UHF and microwave it starts looking like HVAC ducts.
Skin effect
I used to see a lot of ducts in radar technology =)
I thought it was just conduit
The algorithm was trying to get me to watch this all week. I finally relented and I'm now hitting myself for not doing it earlier. Your dad is incredible at explaining this stuff, and his enthusiasm is contagious. I'm a software guy who can read schematics and do some soldering and this RF stuff is half black magic and half "I bet it works if you don't think about it too hard".
I didn't know AM modulation wasn't just effectively talking into a 50,000 watt amplifier and connecting an antenna instead of a speaker any more (talking specifically about those modulators at 28:16). It amazes me after seeing all of this that they were able to stand up stations 100+ years ago, let alone monuments to brute force like WLW-AM at 500 kW in the 1930s.
What a great video!
I've spent many nights listening to the ballgame with my grandparents thanks to this KMOX tower.
73
I always remember listening to the Blues and Cards driving home at night as a storm was approaching. You could always tell when it was getting near by how loud and frequent the crackles in the signal were!
Thanks for the tour.
Just imagine putting that lot at 50kw and more, on board a Ship. As was done in the 60s and 70s on the Radio Ships that served AM to the U.K. and the continent of Europe.
Radio Caroline, Radio North sea International, Radio City, Radio London. The true pioneers of UK local radio.
Radio Caroline still exist today, but licenced on land 4KW on 648kHz at Orford Ness in the South East of England. They run the transmitter on Solar power during the daylight.
Look them up, well worth a visit, and they still have the last Radio Ship, fully kitted out, but connected to the TX site via the internet. Yes they still broadcast from the Ship once a month.
These tours with your dad are great! Very cool to see these sites and the changes that have occurred over the years. Many of us hams get excited about our 100W transceivers and maybe a 1500W amp but these stations are the real deal. Keep up the good work!
I get nervous with my little 5W transceiver haha
My Dad's used to high power... I just remember how much a little 120v shock hurt, and my Dad described RF burns and made me want to give anything in a transmission line a wide berth.
When growing up in Florissant, my Grandfather would have his little portable radio playing KMOX with him either in the house, out working in his workshop, or just siting out on the front porch. On a clear night I can get KMOX 800 miles away in Charlotte, NC.
Amazing stuff. Raises my appreciation for AM station operation. Of course, nowadays there's at least one generation that's never listened to AM radio.
This takes me back to my teenage years. One of my scout leaders growing up was a broadcast engineer (Pete at MidAmerica. Your father will know him, I'm sure.) I worked for him a little after high school and we went to a bunch of xmitter sites. He sounds very similar to your dad. I watched him wind coils, service xmitters, all sorts of stuff. Later, I worked with him on my master's thesis of automating the measurement of AM tower patterns. good times.
Fantastic video. As a ham radio guy who's also been listening to KMOX since I was very young, this was a very interesting video! It's really neat to see all the infrastructure required to provide the wide coverage area and quality audio of KMOX.
I am an Amateur Radio Op as well (W4KDN) and was privileged to experience a VIP tour of the Trans World Radio site on the island of Bonaire (about 50 miles off the coast of Venezuela). TWR runs 440 KW into a 4 tower directional and steerable array. I authored an article and submitted it to QST which was published. This video brought back some not too distant memories of that tour.
I had a hole blasted in my thumb through a glove from a 1kw transmitter, the owner shut the tower down (so he thought, got sidetracked by our conversation). When I got outside to the tower I thought I could still "feel" the energy, and instead of walking 200 ft back to the headend or walking the same distance to the truck for the voltage indicator, just to make sure (With my gear on in 100deg heat after all I saw him open the panel on the transmitter where the breaker is) I decided to skim the ring with my thumb.. not smart.
Nice to see a well-rounded engineer recording just a small part of his years worth of experience on a little-known subject.
Thank you!
I love this. I always wanted to know about AM towers. you are a fantastic creator!
As a radio/Ham enthusiast I enjoy seeing the big boy setups like this. Pretty cool that ATU is the size of a small building. It was interesting to see that transformer ring for the light power. Very cool stuff. Thanks for including the radials this time. Awesome video.
Great video. Brings back memories of my days at KRVN 880 out at Holdrege NE. 50 kW 4 tower directional array. Lots of fun stuff! Thanks for sharing.
Extremely interesting. Always wanted to see the interior of the huts and buildings at radio transmitter stations. Good program. Well recorded and produced.
My father was a ham operator for all of his life, so watching this video was super nostalgic for me. Absolutely love the amount of information in this video!
Well done! Thanks for the in-depth tour. 10/10 and very interesting. Seeing this made me feel a twinge of pride, as KMOX is the AM powerhouse in my region. Soak up all the knowledge you can from your Dad, and men like him, he's a real jewel.
Man I love this video 10/10. It was so informative. I learned so much about am radio towers. All I knew before was they were energized and the wavelengths were impractically huge.
I chuckled at 950mhz studio link antenna called microwave rather than UHF. Its right but its just so strange as someone who worked with 900mhz to 60ghz. We just called everything sub 1ghz UHF.
I mean compared to AM, almost anything is microwave :D
@@GeerlingEngineering So true.
For other viewers here's some comparisons in the wavelength size.
49965.4096666667km wavelength @ 6hz (Teslas wireless power system)
555 meters wavelength @ 0.540mhz (start of AM broadcast band)
176 meters @ 1.7mhz (end of AM broadcast band)
11 meters @ 27mhz (CB radio)
5.99 meters @ 50mhz (6 meter ham band)
2.8 meters @ 107mhz (end of FM band)
2 meters @ 147mhz (2 meter ham band)
68cm @ 440mhz (UHF ham band)
54cm @ 550mhz (best UHF television band)
42cm @ 700mhz (cellular 700mhz band)
32cm @915mhz (ism 900mhz uhf band)
12cm @2412mhz ( wifi)
8cm @ 3.655ghz (Wireless Broadband Services WBS band for licensed fixed wireless)
5cm @ 5830mhz (end of 5ghz uni3 wifi)
1.2cm @ 24ghz (unlicensed 24ghz band)
4mm @ 60ghz (unlicensed 60ghz band)
3mm @ 90ghz (upper band mmwave 5g)
0.9mm @ 300ghz (right before it becomes infrared)
Its truly an amazing thing that people were ever able to figure out that radio waves, heat and light were the same thing before microwave spectrum and radar was a thing.
A.M. antenna systems are very interesting. Thank you to your father and you for this awesome video!
Do you mean AM (amplitude modulation), or Medium Wave (0.5 to 1.5 mhz)? We use the terms interchangeably for broadcast radio, but they each speak to different things. For example, the entire mast being the antenna is because it's medium wave, and would apply regardless of the modulation. Meanwhile hearing echoes of the transmission are because it's AM, and would happen regardless of the frequency.
I guess my point is that I wish the video made these differences a little more explicit.
Wow! I lived in St. Louis in the ‘90s for 5 years and listened to KMOX. I moved to Peoria, IL, and went to work for ROHN designing antenna towers. One of the differences is I spotted is that we would design provide a 3’ high base pedistal which is higher than KMOX’s. The reason was to keep the weeds from touching the base insulator and reduce the varmits from getting on the tower and causing an outage. I recognized a lot of the tower and, guy hardware and lights we would sell.
In another life I was in the electrical world and delt with varmit control in electrical substations. I had to stop squirrels from climbing on the circuit breakers and cutting power to the Texas Medical Center. I designed a squirrel proof fence. Today they have electric barriers in their substations to keep the varmits off the high voltage equipment.
I totally enjoyed the video because I have never had the cooks tour of an AM radio station, much less than one I used to listen to.
I have no idea how this ended up in my feed but this is STUNNING!! It doesn't get more cooler than this!
I saw one of those Buss Fuses displays at, coincidentally, the bus workshop my dad worked at. So when I was a little kid I thought that meant the fuses were designed for busses. And since cars are smaller than buses, using a buss fuse on a car would give it extra reliability.
Haha "Dad why do they always misspell 'bus'?"
Your dad’s expression in the thumbnail is fantastic! 😂
Love the content with your dad, I’ve always been curious how broadcast stations work - I’m a ham and had a college radio show for a while.
My dad works in radio, and i used to walk up to the AM towers. Beautiful sight.
Never touched them, glad I didn't.
Fantastic video, highly informative! down to earth.
Well typically the RF goes out the sides, it wouldn't be as effective going down to earth 😉
A late friend of mine was station engineer of AM station WEMP & what he told me of operation of a am radio station is exactly how you describe it. Thanks for posting this very informative video.
Have you ever visited the Voice of America Museum in West Chester, Ohio? They still have a 250,000 watt transmitter (un powered), and a lot of high power radio stuff. And down the street is an original Blaw Knox antenna (WLW-AM).
It's great to have this shared experience with your Dad ❤
I love these tours. Currently a technician working on various FAA equipment kind of near St. Louis. It’s always so cool to see the kind of radio equipment that I work on, but on steroids! Please keep the coming!
Is that a hard career to get into?
@@duck_rifle5879 they only post them once or twice a year. A lot of times to their based on FAA needs when it comes to location. They like to have people with backgrounds in electronics, radios, etc which a lot of people get from the military. 2101 ATSS is the job title if you want to look it up
I always love everything radio and broadcast related, it is super interesting to see, keep the videos coming!
It is such an interesting industry, I am really glad to work at a broadcast equipment manufacturer.
Felt guilty because I listened to KSHE when living in St Louis during the 70's but I sure remember KMOX powerhouse. Wow. Thanks. What a treat for an ole broadcast Engineer and a High Schooler from UCity. Thanks again for all your efforts. Scott
I was a radio operator in the military '85-'95. Radio/Radioteletype SSB AM.
We used a 15' whip antenna (xmitting about 10k volts RF) on the vehicle for mobile use, but when
we set up we raised a 50 ohm doublet (cut to whatever freq we were assigned). While deployed during the
first Gulf war, we had to set up during a sandstorm. Once the antenna
was raised, I picked up the end of the coax nearest the truck to
connect it. Big mistake. The static that had built up from the
blowing sand was enough to knock the ever-lovin fool outta me.
My whole body jolted and it felt like someone smacked the bottom
of my heels with a sledgehammer. The connector literally arced to
the grounded equipment when we went to connect it.
Man, ive been a fan of you for a little over a year or two Jeff, but i have loved radio and radio technology for years. This stuff is teaching me so much (im trying to get my amateur license for the first time) and its very interesting. Thanks for all of the hard work you put into your content. Also, hope youre doing well with your Chrons. I know that can be debilitating as all hell.
This year has been great, knock on wood! No hospitalizations for 2023! (So far... knock on more wood lol)
Hook up with your local Ham Club and they will have an examiner to get you licensed.
I was waiting for this video for ages. AM Towers are very interesting.Thanks :)
I was the AM transmitter RFTech for WJJZ 1460 Kc. It was my job to monitor the Dog House on an island in the Delaware River. I worked alone 3 Fay’s a week Friday to Sunday 12 hour days. Ours was a 5 kilowatt station. I arouse at four AM and drove to the Marina, then took an outboard motor boat around the cove to our landing. It was a lonely boring job requiring an FCC 1st Class Radiotelephone license. The hourly pay was good, but no benefits or vacation. I left that job for a much better gig with RCA building in the space program. They asked me to change the lights on top of the antenna in the dark. I refused, I was fired! It was always my goal to work in broadcasting , radio and or TV. This job cured me fast!
Absolutely love this video. I've been doing this kind of broadcast work for 37 years. With most forms of entertainment moving to The Internet, Guys like us are a dying breed. Treat your Broadcast Engineer well. 😁
43 minutes well spent. I actually learned a lot from this. Keep up the great content. Hats off to your dad!
Best video on the subject I have seen.
I typically don't watch lengthy videos in their entirety, but this one captured my attention without skipping anything. 💖
Those porcelain insulators are marvels. the little single "petticoats" used for suspending the lowest of the high voltage distribution outside most homes are rated something like 10-30klb tension or compression.
That large one is probably rated 100klb.
There was really short view of a broken one on the ground when they were outside. They're hollow?!?!
@@piquat1I think that was the one that cracked, requiring the rig to hold the tower while they replaced the broken insulator.
@@zoopercoolguy I was a field communications tech. Started out climbing towers but ones less than about 300'. Even those... well there's a LOT of weight there, then the guys and the tension, it's crazy that's all sitting on a hollow ceramic tube. It's crazy enough that they usually kind of come to a point on the bottom to pivot, but that's steel. This is nuts to me and I've been around the "smaller" versions of this stuff.
Kilopound is a cursed ass unit ☠️
Did a TV transmitter site a few years back from the demo of 3 old analog transmitters and associated matching wave guides and coax to the power to the new dishes out in the field. From the ground up it was allot of work. The grounding of the transmitter was all that and then some! Transmitters and dummy load were all water cooled as well so there was multiple pumps and CAN bus for control and monitor. ERP on the UHF band was about double this site in the video. Fun job being there on the first day of operation and switching over from the previous transmitter site.
7:22 austin ring transformer Aren t there many magnetic losses in that open air transformer wouldn t you lose half of the power before energizing the antenna? a radio amateur asking
I am looking into a startup online radio station and it will be all vinyl LP. mastered, with true Full Length Stereo(FLS). the seperation heard will be way better than any station up and running as of today! Mono, will be heard on one speaker as Mono is a one channel mix, not two!
Great video. Very few radio enthusiasts get an opportunity to see the guts of a working station with these details. Thank you and well done!
I love that there's a breaker box right through the wall from the shower.
Just a good prep for what happens if you get too close to the tower!
I was in the USAF in from `90 - `94 as an AWACS RADAR and IFF Maint technician. The Simpson 260 was the meter in our toolbox.
Thank you for your service Mr. Reid.
Back in 1986, my landlord in Germany arranged a tour of Radio Luxembourg's 1,200,000 watt daytime, and 600,000 watt nighttime AM transmitters, located in Marnach, and broadcasting on 1400(1439) kHz. There were three towers phased to allow a north/south radiation pattern which blasted the British Isles. Can you imagine a transmitter with 24 times KMOX's 50,000 watt power!
Radio Luxembourg, the first pirate station!
Thank you for the Contant and remind me of the days when I used to play around in college with RF I really loved it. It was my passion, but I did not follow through with it but I am into telecommunications engineering now, but it would’ve been fun to work at a RF tower.
Geerling Engineering is like the Engineering Explained of RF and radio infrastructure, and I love it!
Edit: I laughed a bit at the batteries being on wooden boards at 16:33, reminds me of the superstitions my grandfather tolk me about concrete discharging lead acids lol.
high power is both fascinating and scary
It just requires a lot more respect!!!!!
Yes, I'm scared of my higher power too
Yes, I'm scared of my higher power too
Never seen an air core transformer like that, it doesnt look very efficient but its doing its job
Nice, detailed look at the doghouse. Well done. I've been a ham operator, an FCC broadcast licensee and a communications tech for over 55 years. Went inside a Navy VLF site once and it's all the same whether VLF or UHF just larger or smaller components. Microwave component construction gets a bit different, but the principles are all still the same.
really glad i found this channel. relatively new (4 years in) to IT tech, and this stuff is super interesting to watch, especially the second half of the video. this guy is really an all around master at his craft, he knows the entire site inside and out. pretty cool
Jeff that's not the kind of anchors they used on the arecibo array, it used stranded steel wire that would be frayed and filled with another metal
Ah, well there you go! They should've used guy wires 🤪
Goes to show how much I know about securing massive cables together!
A splice like what your dad showed is usually the strongest way to terminate cables/ropes, it takes a lot of time to do properly but it can even be stronger than the cable would be by itself. Most ski lifts/gondolas use some variation of that.
Love your content too, would love to see a tour of the KETC tower in south county!
That facility is a great one. Chrys Marlow and his crew take good care of that site.
What do you say, Dad? Maybe for 2024 :)
This crushes entire nerd internet in best possible way.
I can here KMOX in the evenings and overnight from Winnipeg, Manitoba , Canada.1000 miles north. I first got into AM dx in the 80's and I remember tuning in KMOX with my clock radio!
I’m a radio fan but not great at electronics, this was great fun. Much respect for RF engineers.
Absolutely fascinating!!!
Please keep the transmitter content coming!
As someone who ran a highly available data center I love how much crossover there is with this radio site! I wonder if they have as many problems with wear on the ATS contacts as we did, had to have the contacts replaced twice in 8 years.
They did seem to have issues on certain switches-from my conversation with my Dad (some was cut for time, on this long video), they had to maintain the transfer switches more than any other part of the power delivery chain.
There are an awful lot of lessons hard learnt in this video.
Also, if anyone has tried to do RF tuning and antenna design know it is pure magic :D
Impressive how Dad explained things so well without much technical language. I’m sure he knows the technical aspects - in depth - and for him there’s no magic at all.
34:23 you forgot to talk about the most important safety device. It’s the sage EAS box (the blue) box.
What a nice man. He explains things very well, and the rapport between them is nice to see
Well, do not touch it.
At around 10 minutes, you can hear the broadcast coming from an electrical arc??? Mind blown!
I've heard news stories where some kid, invariably a young male, who was electrocuted touching the antenna, despite all the warnings.
Thank you for the thorough tour. I was a broadcast engineer for 40 years. I enjoyed every part of the video.
KMOX, was one of the first stations I
DX'ed back in 1960, when I starting
listening to MW from the NY city area.
It was an RCA portable with mini tubes
and an old type battery.
Some years ago, my wife and I had friends in Dorsey, IL. not too far from
KMOX site. 😊
So glad I found these videos. Thank you for posting them! Give my best to your dad.
Will do!
Your dad looks 100% modern American institutional engineer. I love it! I grew up with these guys at Northrop Grumman, Rockwell, and Boeing and they all wear the same collared shirts and khakis! Lolol. God bless this man for agreeing to do this tour… he has a great personality and ability to make the complex seem more simple! Great editing too.
I really like how when I just listen to the audio you two sounds so alike it almost sounds like it's the same person sometimes. Or like there's an older and younger version of the same guy having a conversation
Thanks for the tour of the station, I work around that kind of stuff myself and was laughing at some of the same things I see stored at almost all broadcast facilities. Very well done.
Very cool ! Even cooler is the relationship between you two. I love getting questions answered.