I was the ABC-Disney midwest regional engineer and this facility was one of the stations I was responsible for.

Warmed my heart knowing the engineer forgot to turn on the dummy load fans and owned it. I have had plenty of big mistakes at work. Much respect for businesses that accept human element in any financial machine. That radio station has got to be a great place to work.

The most important machine: The coffee machine.

Something special about seeing a son give dad a platform to discuss his life's work. Great content too !

You also need to show a TX site with a "poor man's" phasor, different lengths of feedline coiled in the basement to feed the towers at different phase angles... I've seen a couple of those at small stations.

This one was EXTREMELY interesting! :) It's very rare to see the technology for transmitting at this kinds of power. We were joking 30 years ago that some Italian HAM operators are using the heat of their power amplyfiers to heat whole towns, the contest beeing limited to 50W and they were bending our antennas a few hunred kilometers away :D

I howled when your Dad said “Measure twice and cut once”. My Dad used to repeat that to me all the time! Your Dad is the bestest!!❤

Looking at your radio propagation charts reminds me of when I tool Quantum Mechanics and my prof, a ham radio operator, told me that the same partial differential equations governing electron orbitals were used in antenna design.

I have so little knowledge about radio, and electrical engineering, but I still just absolutely am fascinated by this channel and the stuff we get to see. Great work folks!

TLDR. It’s a phaser. Is splits signal into 5 identical signals and shifts the waveform ( time). So if you are between the path of 2 towers u actually receive both signals mixed are in phase and not shifted to sound hollow ( telephone voice). Reason for the extra towers is you send less power to a particular tower to shape its coverage area - you don’t want your signal interfere with another station to Ie sw on same frequency or costal city do not need to have 100 % coverage of the gulfs of mexico

A couple of months ago I commented on another channel praising Starlink as brand new technology, that phased arrays are nothing new and have been around for almost 100 years. I was remembering that post and just then you inserted a picture of a Starlink dish. 🙂

I used to be a Broadcast engineer in the 80s and this bring me so many memories. Thanks for sharing. BTW my broadcast life was in South America, dealing with equipment from the 40s next to a Harris DX50. 😊

What, no poking things with hot dogs?

Jeff: "There's a DX50" Me: •looks for a 486 desktop computer•

Great to see. AM stations are dropping like flies in the UK, some stations paying out fines to the regulator rather than pay more in energy costs to keep running. Even the big 198KHz BBC Radio4 transmitter that reaches a huge area of western Europe is slated to end transmissions, oddly it is needed until domestic electricity meters have been updated to use mobile/cell networks as Radio4 LW broadcasts a signal which switches meters between day and night electricity tariffs.

You guys need to visit the AM site in St Cloud, MN where there are four stations (WBHR, WMIN, WVAL, WXYG) multiplexed to share a single (5 tower, IIRC) DA, each with a different pattern.

I could watch videos of Jeff and his dad for hours, they are so good together.

My first job out of college was with a company who (among other things) built and installed phasing&matching panels for AM stations. It's a unique experience working with a circuit that you need to "bend from the knees" to manipulate.

Thank you, this was fascinating! Even little tidbits of information like your father's passing comment about PEP stations. I had to look that up. Cool stuff!

Always love these videos with your dad.

Thanks for your great presentation Your chanel is awsome! I was not really focussed on antenna and RF but the way you transmit your passion is catching our attention for sure!!

This is really cool, and it makes me appreciate how much engineering goes into radio.

Really appreciate videos like this, a rare glance of the inner workings of these systems.

I love this video series! The way we transmit radio, in particular, is an amazing feat of physics and engineering. All the interplay of phases, directionality, wave forming, etc is intense. I used to know an old tower rigger that had been around since the AM deployment days (by contrast, my specialty is in WWAN and P2MP) and he used to show me all sorts of wild equipment at the towers we worked at.

Very cool, I never quite realized why I see clusters of multiple towers. Also cool to see the amount of equipment that goes into running a station like this. Thanks for sharing!

Geerling Engineering deserves a TV Emmys! Thanks to both of you for the content.

Having listened to STL radio for most of my life, this channel is unbelievably cool

just fantastic, really enjoyed your video, keep up the good work!

thank you my third year was RF engineering and I enjoyed this very much!!!!

Hope you keep em coming, Its very interesting for an RF enthusiast like me

"...just put power in me and I'm gonna heat up..." Perfect for those long cold winter nights, a very useful apparatus if you ask me =)))

Very informative guys! Thank You!

Very cool stuff! Thanks for sharing

I’m so glad the AI put this in my feed. I subscribed. I love that you got the engineer to come and explain his mistake to the world. I love that. I love their sarcasm. It’s very endearing.

Fascinating! RF engineering is still black arts to me, let alone high power RF. The build quality obviously looks very good there, and all this copper bonding throughout the entire site... Most impressive. 5:35 SCE to AUX! Ha. And proper respect to Jeff for the Debian tee. That's been my distro of choice for 12 years.

I love these videos. Thanks y'all!

They had some of that in the 90°s while I was going through the military. Was nice to know they believed in backups. Also was a bit easier than the newer satcom stuff.. Poor hotdog..

This is so nice, we have only a few look of this kind of tech and it very interessting! Thanks

i really love these radio station tower videos!

This was fantastic! Jeff I love this kinda content! THANK YOU ! But I’m gonna need more! Great video but I could have watched an hour worth easily

I love phased arrays. I have two Wolf River 213" verticals I use in-phase 1/2 wavelength apart, mobile and at home. Makes a very high gain bi-directional pattern. They just need two identical non-resonant lengths of coax after a splitter (18' for 10 and 20 meters for 66% and 80% VF cables). I made 10 contacts with 10 different countries the first night, in the city, power lines near 3 sides of my yard, Amazon RG8X coax, and on 100 watts form a 90's radio. I eventually want to cut some coax (using an excel sheet calculator I made) to make a 90 degree phased array with the two 1/4 wavelength apart. Makes a cardioid pattern that's actually less gain, but more compact if I need to do 30 or 40 meters. Knowing how to use formulas in spreadsheets and MMANA are your best friends when it comes to antenna planning and design.

Really good questions. Intentionally basic - you obviously more or less already knew the answers to most - and perfectly designed to make this tour interesting and educational for the layman

Absolutely wild! Gotta love AM radio!

fantastic video! I now have a newfound fascination with radio towers :D

Oh how fondly I remember Saturday nights during the 1980's with KMOX radio and their "green and red hot watts of KMOX radio." Saturday night jazz radio. It was fabulous!

As long as it's a Geerling Engineered voice, then it's perfect!

Great watching you guys together. Not even my field, but it's just interesting.

Wondeful report!

awesome video, love this stuff

Super interesting! What a completely different world!

EXCELLENT THANKS

I wasn't expecting this video to be about AM tower arrays, but I sure am glad that it was! 😍

A giant HF phased array beam steering system. That's amazing.

Superb!

I would love to see or talk to one of the design engineers. This stuff is so coool!!

7:07 - Amazing video! I couldn't stop watching it. But I think the real question we need answered is the Lil' Tree (Black Ice) hanging there. I just know it serves a very significant purpose.

Prodlen made 51. Ohm coaxial cable, used by GE that made made radio and T.V. antennas and transmitters. GE actually supplied complete "turn key" studio and transmitter equipment for radio and TV stations in their hay day. (just like RCA and eventually Harris) Ron W4BIN

I wish we had a series of towers adjacent to my old elementary school. Imagine the fun and games! 73 Dad & Jeff

This was great.

When I was young, there was a misconception among adult electronics amateurs and even professionals (who didn't work in radio) claiming that the towers were safe unless a person climbed to a dish or an assumed "active" element near the top! Granted, the tower near my home did happen to be safe: it wasn't even fenced and had no warning signs that I can recall. We played on its concrete pad any time we were near it with adults. The thing had a couple large electrical enclosures near the base, but no transmitter building.

Nice DX-50, I have the badges of a white le DX-10 whom met a demise due to a mouse bridging two components on the main board lol Also 8towers is crazy, but we once upon a time had 15 towers on one of our sites here in the Toronto area when it was 790

A secret I've kept to myself as a kid until now is i used to "ahhh" into pedestal fans when switched on and the same phenomenon happened too 🤯

And to think I complained as a kid when I had to fiddle with the rabbit ears on our Sears TV. And, yes, I do know this is radio, but the transmitter towers for the radio station we listened to back then were less than a mile from our house and came in clear even on my little portable radio with the broken antenna.

Cool! Please make a video explaining how it works. Would be great to see it modelled on NEC!

I never would have guessed the danger of a radio tower. Wow

Genius!

I listened to Radio Disney up til the end but I never could imagine how they had enough listeners of pop music on AM radio in the age of iPhones and Spotify to make the business worthwhile.

Vern Jackson with the recap of the week!

My lovely horse... running through the em fields and dangerous voltages

This explanation reminds me of having to tune my base antenna on the Coast Guard LoRAN-C station.

All of the phased-array stuff feels like the future, not 100 year old tech.

"and its not like its near an elementary school". Imvho, whoever climbs a fence to get to a radio tower that is active and touches it, got that coming.

Brilliant ... I love it ( Radio Astronomer)

Awesome video! This is why people disagree about whether am stations come in better at night. All things being equal the signal travels farther per watt but the stations sometimes have to compensate to avoid interfering with each other. As a Ham it's always fun when the bands open up though and you find yourself talking to people from ridiculously far away. We often use pl tones to reduce unintentional interference between our repeaters.

At KNAU we had 100,000 watts 30 miles away remote, at KBAQ in Phoenix/Mesa we had 150 watts up the pipe to a 20 element Yagi antenna, 3,000 watts erp. At KBAQ we were a whisper in a Room full of Shouts!

Those NITE pattern sections tended to go BOOM! if fed with DAY power!

I like Aaron's sense of humor. Could you explain how the antenna pattern and power level is verified to be compliant?

This stuff is so damn cool

1:36 beam forming?

0:44 Oh boy. That would nuts job to do.

Putting aside regulations, laws, and other forms of "momentum" that contribute to why we have AM radio today, if one were to design an entirely new radio system today, specifically without historical influences, would AM radio be a technology that we would want to deploy? Or is the continued use of AM more of a consequence of historical momentum?

See, yall are like "I cant believe people care about this boring stuff" .......YES WE DO!!! WE EXIST!!!! AND WE ARE UNDER-ENTERTAINED!!!! I for one was always interested in the how what why and such of what went on inside the radio huts under the towers, how radio stations went from studio to the run leading to the antenna, all of that 'boring' industrial stuff. I didnt much care for production (although the control systems for TV is pretty interesting, all the video switching and such), didnt much care about antenna design and propagation etc, but the middle ground, taking a completed signal in, shaping and cajiggering it boosting it splitting it, what ever, I wanted to do that! I wanted to know how it worked! I WANTED IT!!!! And no one ever really showed it off more than 'look, here is our transmitters (looking down a row of cabinets). And now sports!', didnt know anyone that did it or was also into it, so I always just got to let my curiosity eat at me while driving by a tower site..... So basically......FEED ME MOAR!!!!!

Sweet!

I just can’t stop thinking of WKRP when watching these. Phone cops man!

So it's a phased array! Awesome! Never thought that was used back then, and in such big machines! How does the phasor actually work? Delay lines?

Day/Night: I had no idea, but I had wondered about multiple small towers at transmitter sites: At 5:55 I like the way the anodyne appearance of all those panels has been broken up by a cheapo plastic thermometer in an almost anarchic manner - which given that Disney put money in it almost blows my mind.

I wonder if the FCC licenses them for effective radiated power or just wattage? as this is a phased array it can obviously give you a lot of gain in any given direction. With Ham radio most bands are limited in wattage but some take gain into account For example on 60m (5250-5450 kHz), if your antenna offers 3 dB gain, your maximum legal output power can't be more than 50 W (50 W plus 3 dB gain equals 100 W Effective Radiated which is the legal limit there. Great video, interesting to see what the big boys get to play with.

17:55 Did that sausage just talk?

So basically this huge phaser cabinet thing is an analogue beam forming apparatus for the broadcast transmitter to shapen the energy distribution according to the station's FCC license. Nowadays they likely would derive the phases of the individual transmitters (one per mast) digitally from a single quartz, isn't it?

Big Vern Jackson with the recap! Atta boy!

It was new to me that you can listen radio with a sausage. :)

Yeah... so... if I'm here with family, why would I ever be out to impress anyone? Literally life and death and no one can see it.

Very interesting. I've only ever maintained a dual tower 5kW AM site. Any update about the missing tower at WJLX?

Wow. I am at kilowatt here (J1000) that I have to drop to 56 watts sunset to sunrise. Not dealt with phased antennas yet but cool to see how they work. Antenna design/theory is still voodoo to me. I have replaced power modules and had to mess with the ATU when we took some stuff off the tower. I can hook up a rigexpert now but still have the old way. Big baklite meter with huge alligator clips that go on either side of the coil. Don't quite know how it's used but seen it done and it belonged to one of my mentors that's silent key so it sits on my shelf as a memory. And yes every tower site I have has box fans.

That dummy load has a set of high power wire wound resistors and it dissipates a lot of heat.

One button to push reminds me of a muppets sketch where miss piggy s job was to push one button but naturally she blew it.

FYI: Vinegar gets rid of the smell of scorched electronics. Source: OC Fire Authority

Did anyone notice those horseshoe/partial rings on the ground around the antennas??? I couldn't take my eyes off them trying to figure out what they were..... I THINK they are areas of growth of the grass... (at least that's what it looked like when the drone came down a little lower) - they reminded me of the 'fairy ring' phenomena that is seen in the scrub brush of the Australian outback and the in Namibia desert grass too... no one has figured out what causes them but they are circular areas of non-growth with the outer edge of the circular having MORE growth than the typical amount we see throughout the entire area.... so they are like bald patched in the grass, with a small ring of higher growth around the edge of the 'bald spot' .... the two main theories of what cause them are the plants self organizing to collect the little bit of rain that falls in these deserts (but that seems quite unlikely to most people) and the leading theory is termites underground eating the roots, or kills the grass because their 'home/hive' is directly under the rings... but that doesn't explain the higher amount of growth around the edges..... -SOOOOOoooooo after seeing these partial rings around the towers, and ONLY around the towers (I don't see them anywhere else except in the plot of land with the towers on them) I started thinking that MAYBE it has to do with the electrical currents from the grounding of all the systems to make the towers go brrrrrrrr 🤣 ( sry I had to lol ) BUT then I realized that we don't see these horseshoes/rings in the fields around the towers plot of land because THEY ARE FARMED! duhhhh!!! Whatever causes the rings gets tilled over year after year when the farmers are doing their thing... so it all gets mixed up at least once a year, so it doesn't have time to form any noticeable pattern, plus there is no grass there either..... - I just thought of them possible being because of the cables that come off of each tower to stabilize them and hold them up, but after looking at the footage again closely there seem to be quite a bit more of these "rings" than cables... with 3 cables on each of the four side, you might thing that there would be 12 anchor points in the ground, but I'm fairly certain there are only 4 anchor points for each tower because the 3 on each side appear to all go to the same anchor point (which I would think isn't redundant as it could be and only one failure takes out all three on one side, but I followed the 3 on one side they all seem to land at one point 🤷‍♂) - - Okay... so WHAT ARE THEY???? I want to go with the 'termite/insect/creature' explanation but these things aren't the same as the tradition fairy rings, plus they aren't the same thing.... the tradition one remove EVERYTHING growing in a circular area with higher growth around the edge and are spaced out in a fairly ordered manner.... like each 'fairy ring' stays away from all the others, and they are all pretty much the same. These are semi-circular higher growth LINES that have to pattern to location and each one is different for the most part..... So I'm gonna say that they are each caused by different things. - - IF I look in the shot @ 17:31 there is a house with a brown roof on the right half of the screen ... they have a yard of similar colored grass to the left of the house... I don't see ANYTHING that looks similar to what we see around the towers, and I REALLY don't think that area is regularly plowed like the rest of the fields we see.... so WHY aren't they over THERE????? What makes the TOWER PLOT SO DIFFERENT??? - - - - What do you all think??? Any ideas??? I'm at a loss... but I REALLY want to know if these two things are related..... they are BOTH VERY STRANGE! :)

I can’t remember if you covered this already, but I read recently that some car manufacturers are no longer including AM radios in new cars. Crazy!

Why the teaser screen that implies an AM DA is some kind of weird audio harmonic or band splitter, versus working on A3 modulated MW RF? Why also suggest phasor coils are adjusted mainly if capacitor values are unstable, but not even a mention of the real reason, that the biggest element of an AM DA is actually ground conductivity of the earth, and that changes regionally with soil or rock types, and with daily and seasonal weather, being higher in wet or cold conditions? Why the teaser screen that implies an AM DA is some kind of weird audio harmonic or band splitter, versus working on A3 modulated MW RF? Why also suggest phasor coils are adjusted mainly if capacitor values are unstable, but not even a mention of the real reason, that the biggest element of an AM DA is actually ground conductivity of the earth, and that changes regionally with soil or rock types, and with daily and seasonal weather, being higher in wet or cold conditions? One of the trickier AM DA's I reworked over the years was on a tidal salt marsh, with an 8 foot tidal range, that went from leaving walkable marsh grass, to precarious catwalks that in extreme conditions were submerged and salt water almost up to tower bases. I constructed 50 foot square raised ground radial sections around the tower bases to reduce the electrical shift, dropping into the soil/high tide ocean between towers otherwise. I've also done extensive ground conductivity field studies (including carrier offset w/ FCC STA low signal level work) mainly in the Northeast, to show FCC presumptive maps are often wrong for certain regions of low conductivity soil, and so more signal is allowable than FCC map based pattern designs suggest is allowable. Not sure if the names Carl Smith, Ted Schober (RadioTechniqes), or Glen Clark are familiar, but I've done collaborative projects linked to all of them, with Glen to refine AM DA design and adjustment software tools. It sounded like that Tx site had a lot of blower noise, and dad was struggling to talk without shouting, and that impacted his concentration compared to tours of more familiar (to him) and quieter facilities? Another missed important detail.... AM DA's are designed (hopefully) for stability, and to operate with a stable flat Tx load resistance over the modulation bandwidth, as well as to not need excessive adjustments for instability. More towers and cramped sites often make higher Q hard to avoid. Minimizing phasor adjustments is also important when common point impedance is shifted, not just as to resistive component at carrier frequency as is FCC license designated, but as to sideband resistance as ideally a flat curve top, and reactance as zero'd at carrier and equal and opposite sidebands without extreme tilt. Those traits, and not just working on paper for an FCC license (eg, anyone designing 40:1 nulls is insane, but it's been done), are what distinguish the "magic" of good consulting engineers, from average, or ones best to avoid.