If I touch this tower, I die 

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 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

@@ntfx_org7603maybe 100 years ago , but i can pretty much guarantee that’s not the case. Also, kinda an odd placement choice for your comment. Regardless hope everyone is having a pleasant day. Take care.

@@ntfx_org7603 I think a deep sea divers lifespan is shorter than 55. Also electrical power workers on power lines differ from what radio engineers are doing. It is easier to shut down the power feed to a radio antenna.

Yeah, my dad loves tech

but, now, also immortal

mooi! dat soort verhalen proberen we vast te leggen bij BOEi! twee jaar geleden iets van over de PNEM mogen maken. Waar zat je vader?

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

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

literal porn.

I’m seconding this. I love these episodes.

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

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.

Skin effect

Wave Guide en.wikipedia.org/wiki/Waveguide

I used to see a lot of ducts in radar technology =)

I (Jeff) don't know more than like 0.00001% of all there is to know about antennas and RF... but it sounds like this is a plausible reason for that loop! My Dad mentioned that some parts of the AM signal path were managed by consultants who (these are not his words, they're mine) knew the dark arts of properly tuning AM towers for maximum efficiency. He knows a lot more on the side leading up to the ATU, but I think he was primarily FM for half his career, so learned a lot at KMOX! (Always keep learning... you never know much except what you don't know)

how the hell do people figure this stuff out?!? it's nuts!

@@mcpr5971 Engineering Biatch..!

Yep, exactly. The rise time encountered during a lightning strike is so quick that it cannot travel around that loop before being directed back to the path of least resistance (ball gap) for that tremendous amount of electrical energy, so that MOST of it is conducted to ground.

@@GeerlingEngineering If you think that's the dark art of engineering, imagine creating and maintaining a 5 or 8 or 10 tower phased array with day and night patterns! All of those from the 1930s or 1940s done in the engineers' heads.

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

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.

I never got to see the original Westinghouse transmitter, only saw pictures, but those things were massive (and impressive!).

That's a well credentialed Elmer.

Always fascinating to us Radio Nerd-Geeks! Why? No clue. Just is. LOL

Are you saying there are vacuum tubes that are five feet tall?

As a 1830s kid i can understand

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

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 ….😉

Yeah weird. Reminds me of when Laurie Partridge was hearing radio on her braces 😂

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!

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.

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.

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

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.

Just a good prep for what happens if you get too close to the tower!

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.

Haha "Dad why do they always misspell 'bus'?"

Well typically the RF goes out the sides, it wouldn't be as effective going down to earth 😉

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

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.

Thank you for your service Mr. Reid.