Field notes · all posts · DRAFT: Keanan's edit pending
Three airports in one day (KPWK, KORD, KMDW)
I used to work with lofiatc.com open in a tab most days, so when it went dark in 2024 I was sadder about it than I expected to be. Then I had a thought: what if I recorded the transmissions myself and turned each airport into an album?
It took a minute to get there, but this is how the first iteration of that came together. It involves three Chicago airports, a twelve hour day, one rented Fiat 500 Abarth and a whole bunch of radio equipment daisy-chained into my laptop. The end result is something I'm really proud of and I can't wait for you to hear it. If you're looking for the behind-the-scenes story, read on.
The part where I learned what an antenna is
I'm generally not a hardware nerd or a radio person and my first attempt at a test run of this project was using a handheld ham antenna propped on the trunk lid. I really struggled to get any consistent signal and it was mostly just noise.
After doing some research (with the help of Claude) the fix ended up being a $21 antenna with a magnetic-mount (and one more adapter). Between the antenna and the software-defined radio (SDR) sits a filter that keeps all the non-airport radio frequencies) from drowning everything out. For anyone who wants to build the chain the whole setup was: antenna in the middle of the roof, coax, adapter, airband filter, RTL-SDR, USB hub, and a MacBook Air running SDR++.
The night before, I tested it from the roof of my building, fourteenish miles from O'Hare and I was able to get a signal! That's when I started to get excited.
9:45 a.m.: Chicago Executive (KPWK)
On the morning of, I picked up the car (thanks Turo!) and jumped on the expressway to head to the smallest of the three airports, on purpose, as a warm-up. Chicago Executive is a smaller field in Wheeling with a proper viewing area off the frontage road. This meant there was a parking lot and that the runway was right in front of me and theorhetically would be the easiest to record.
The first problem was that I wasn't hearing any audio. I spent ten minutes checking cables before finding that SDR++ was politely sending the sound to a speaker that no longer existed. With that sorted, we were hearing the radio transmissions!
I had expected a relatively quiet morning, but instead there were business jets, Cessnas, and a parade of propeller planes I couldn't quite identify all at once! The parking lot gradually started to fill up with people eating lunch out of their truck or sitting next to their kids and grandkids. The viewing area is a real place that real people go to hang out and watch these planes, and I think that's pretty cool.
This first recording session ran until about noon and when I analyzed the audio later, this particular ATC turned out to be the cleanest channel of the day! Not entirely surprising given I was able to get right net to the airport, but a great start nonetheless.
4:50 p.m.: O'Hare (KORD)
After a detour in the suburbs that pushed the exact timing of my plan back a bit, I headed to Chicago's O'Hare International. On my way there, I checked the weather and realized the wind had changed. This meant that the best place to listen in would now be the cell phone lot on Bessie Coleman Drive. In addition to being free and without much scrutiny, when the planes are using the east-flow, they're low enough that you can read the name off the bottom of each one, which is a bonus.
At just before 5PM, with a temperature of eighty-one degrees and scattered clouds, we started recording.
It turns out, late afternoon is when the world arrives at O'Hare. The transatlantic and transpacific heavies come in from their international origins and I saw more different paint jobs on airplanes than I had in my entire life before that.
6:55 p.m.: Midway (KMDW), golden hour
After spending about an hour at O'Hare, I headed down the Tri-State for the final airport of teh day. Turns out, the top floor of the terminal garage on Cicero has about three-quarters of the airport in view, costs a couple of bucks, and has no sign saying you can't hang out there (and nobody came to check on me). Midway airport is home to most of the Southwest Airlines traffic in Chicago and that was almost exclusively what I saw here. Given that the sun was going down, it was the calmest hour of the day, and some of the best photos I've ever taken of an airport.
I also had the radio misconfigured here for about 45 minutes, which means I caught forty-five minutes of the airport's automated weather broadcast, but it will make some nice additional background I'm sure.
What we had at the end of the day
By the time the day was over, we had three raw spectrum recordings and three audio recordings of a specific frequency that we wanted to monitor. Analysed afterwards that means we captured 4,740 individual transmissions, about five and a half hours of voices across forty channels.
Every airport will become an album with real transmissions overlaid onto lofi music and titled accordingly. O'Hare comes out first (and may already be out by the time you read this!), then Midway, then Chicago Executive.
I'm calling it Final Approach Radio. It's back and it's here to stay. You can listen on Spotify, YouTube, or right here on finalapproach.fm, complete with the adjustment sliders that made LoFiATC worth loving.
As far as more recordings, San Francisco is next, with the major New York airports shortly after. If you want your home airport on the list, just let me know and I'll start figuring out where to park.