From:
From the Station to SDR
There is a fairly straight line running through a lot of what I have been doing with radio over the last couple of years, although it does not always look like one when you look at the individual projects.
It really starts much earlier.
When I was young, I spent time around a radio station. Being around a station meant that radio wasn’t some abstract thing happening inside a box. There were antennas, cables, transmitters, receivers, meters, connectors, equipment racks—the physical machinery that connected a building to something you couldn’t see. Radio was something you could build around. You could look at an antenna and know that somehow that piece of wire, metal, or tubing was interacting with an invisible world outside.
That stuck.
The fascination wasn’t necessarily with broadcasting itself. It was with the idea that there was an enormous amount of information moving through the air all the time, most of it completely invisible. You could construct a piece of hardware, connect it to a receiver, turn a dial, and suddenly something that had been nowhere in your immediate physical environment appeared as sound.
That led naturally to making antennas.
There is something particularly satisfying about building an antenna yourself. It is primitive in the best sense: wire, metal, connectors, dimensions, orientation, ground, impedance. You make something, put it somewhere, connect it to a receiver, and discover that changing a few inches of wire or moving the antenna can completely change what you hear.
Over time the antenna became less of an accessory and more of an instrument.
The experiments gradually moved toward the question: What is actually out there?
FM. AM. Shortwave. Broadcast television. Whatever could be received. The interest wasn’t limited to a particular station or band. It was the broader landscape of radio—the geography of signals, propagation, interference, local transmitters, distant transmitters, and all the strange things that exist between the obvious broadcast services.
That is also where the nostalgia for older free-to-air broadcasting fits in. Television and radio used to feel much more like something that simply existed in the environment. You put an antenna up and there were things in the air. Modern communications made much of that invisible infrastructure disappear behind cables, subscriptions, streaming services, cellular networks, and the Internet.
But the signals never really stopped.
So the project became, in effect, an attempt to rediscover the air.
The hardware gets smaller
Eventually the traditional radio approach ran into a limitation: conventional receivers tend to give you a particular function. One radio does this. Another radio does that. A television tuner covers a certain range. A shortwave receiver covers another.
Then came the idea of using computers as radios.
The Raspberry Pi became an important part of that transition. Instead of treating the computer as something separate from the radio, it could become part of the receiver itself. Software could define what the hardware was capable of doing.
That led into SDR—software-defined radio.
The Nooelec NESDR SMArt and the Ham It Up upconverter became the bridge between the physical antenna experiments and the much larger world of software-defined reception. SDR++ provided the interface: instead of turning a physical knob on a conventional receiver, the computer could expose a huge section of spectrum visually and let you move through it.
That changed the experience.
You were no longer merely listening to a frequency.
You could see the radio environment.
A signal became a shape on a waterfall. Bandwidth became visible. Noise became visible. Interference became visible. You could see signals appearing and disappearing. You could move around the spectrum and ask what each thing was.
The receiver became less like a radio and more like a window into electromagnetic activity.
Then came the antenna obsession again
Once SDR entered the picture, all of the earlier antenna experimentation suddenly became more meaningful.
A poorly positioned antenna wasn’t simply producing “bad reception.” You could watch the consequences in the spectrum.
An antenna could become directional.
A cable could introduce problems.
A signal could appear stronger or weaker depending on location.
The apartment itself became part of the experiment. The east-facing windows mattered. Local terrain mattered. Madison signals could be obstructed. Dubuque had its own particular limitations. The physical environment stopped being background information and became part of the receiving system.
That is where ideas like an RF signal-strength meter and an eventual physical antenna-switching system came from. Instead of simply connecting one antenna and hoping for the best, the goal became something closer to an actual receiving station: multiple antennas, switching, measurement, scanning, logging, and eventually automation.
The old instinct—make an antenna and see what happens—was still there.
It just had computers attached to it now.
Raspberry Pi becomes the radio computer
The Raspberry Pi 5 pushed that idea further.
The Pi stopped being merely a little Linux computer and became a platform for the entire radio experiment. SDR++, networking, storage, GPIO, DAC hardware, and eventually the idea of running SDR remotely all started converging.
The Pi 5 build—with the DAC Pro HAT, PoE HAT, SSD and cooling—was part of a broader realization that these small computers could become dedicated appliances rather than conventional desktops.
That eventually connected with the HP EliteDesk systems, particularly the idea of Thing 1 becoming a headless SDR/radio-monitoring machine that could start SDR++ server instances automatically.
That is a significant conceptual step from the kid around a radio station.
The original experience was:
antenna → receiver → sound
The newer system is closer to:
antenna → SDR → computer → network → storage → analysis
And eventually:
antenna → SDR → automated observation → database → interpretation
The radio doesn’t even have to be in the same room as the person listening anymore.
And then the radio became a laboratory
The Arduino interest fits into the same trajectory.
The Arduino wasn’t really a departure from radio. It returned to the physical side of the problem.
GPIO, sensors, RSSI measurements, LEDs, switches, potentiometers, meters, antenna switching—all of those things provide a way for software to interact with the physical radio environment.
That is why the idea of an analog RF signal-strength meter was appealing. It brought the invisible signal back into physical form.
A needle moving because a signal exists is a very different experience from reading a number on a screen.
It connects the modern computer-based system back to the old hardware intuition.
And the same thing happens with the various connector pieces, BNC fittings, miniature plugs, attenuators, potentiometers, breadboards and other bits of hardware that accumulated along the way. They are not necessarily parts of one finished device. They are pieces of an experimental vocabulary.
You can make something.
Connect it.
Measure something.
Change it.
Try again.
That is the underlying pattern.
From receiving stations to an instrument for exploring the air
Over the last couple of years, the project has gradually expanded beyond “I want to listen to radio.”
The idea became something closer to:
I want to know what is in the air around me.
That includes ordinary broadcast radio, television, shortwave, unusual transmissions, distant signals, local interference, propagation changes, and eventually things that aren’t necessarily intended to be listened to in the conventional sense.
That is why radio astronomy became interesting too. It takes the same fundamental curiosity and pushes it outward.
Instead of asking only Which station is this?, the question becomes:
What physical process produced this signal?
The antenna is no longer just a way to receive entertainment.
It is a sensor.
The SDR is no longer merely a replacement for a radio.
It is an instrument.
The Raspberry Pi is no longer merely a small computer.
It is the control system.
And the network of computers—Thing 1, Thing 2, the Pi systems, Arduino/ESP32 experimentation and eventually local AI—starts to look like the beginnings of a distributed observation system.
The funny part is that it all comes back around
The most interesting thing about the whole progression is that the technology became dramatically more complicated while the underlying motivation stayed almost exactly the same.
A kid around a radio station sees antennas and equipment and wonders what is happening in the air.
Years later, that same curiosity produces homemade antennas.
Then receivers.
Then SDR.
Then spectrum displays.
Then Raspberry Pis.
Then remote SDR servers.
Then signal-strength instrumentation.
Then antenna switching.
Then automated scanning.
Then databases and AI.
The equipment changed.
The question didn’t.
What’s out there?
And perhaps more importantly:
Can I build something that lets me find out?
That is the thread connecting the station, the homemade antennas, the little pieces of RF hardware, the SDR dongle, the Ham It Up, SDR++, the Raspberry Pis, Thing 1, the experiments with Arduino and GPIO, and the larger idea of building a machine that can pull as much of the electromagnetic world out of the air as possible.
It isn’t really a collection of unrelated electronics projects.
It is one project that has been slowly revealing what it actually is.
A return to the airwaves—this time with the ability to see them.