I was finishing up Brandon Sanderson's Rhythm of War. Then I was browsing NetFlix, and realized Oxenfree was available through the service, so I started playing it.
These two media are not related. Rhythm of War is about magical people caught in a war between fragments of a god. Oxenfree is a video game about mundane teenagers stuck on a creepy island.
But I had a moment when these two media blended together.
In Rhythm of War, one group of characters are exploring how the planet's natural tones (sounds and rhythms) affect the different forms of magical light.
In Oxenfree, your character has a radio that picks up paranormal broadcasts and affects things on the island.
CRASH! my brain slammed these ideas together!
What if Mages in a story can tune into various magical frequencies. They can then amplify, modulate, or decompress the frequencies to cause specific magical effects.
So one frequency might cause combustion, but another might link the mage and a target so they can speak telepathically.
I started researching radios. I remembered that some radios had literal crystals for diodes. I watch videos and read about them. I refreshed my understanding of AM vs FM, and the fundamentals of electromagnetic waves, carrier waves, wavelengths, crests and troughs.
Here is what I came up with.
Coherers
A world, probably secret-magic urban fantasy, where a very tiny minority are sensitive to paranormal broadcasts. These people call themselves Coherers, while others call them devils, witches, or sorcerers.
Broadcasts
There are about 10 known broadcasts. I haven't set them all down on paper, yet.
Each one has a unique strangeness to it.
For example, if you tune into the one for combustion, you hear chanting in what sounds like a Latin-based language, but has proven to be indecipherable. If you tune into the one that allows you to manipulate electronics, you hear a stereo-phonic screeching that seems to run from ear to ear and back again.
Coherers' Tools
There are crystals that coherers prize. Different crystals help the focus of a particular broadcast. So maybe a red one for the combustion broadcast, a cyan one for controlling electronics.
Then there are the wands, basically antennae the Coherers can use to make accessing broadcasts easy.
Coherers' Banes
There are items that negate the broadcasts. Faraday cages will prevent a Coherer from accessing any broadcast, and jammers will make tuning in difficult.
There are those that hunt the Coherer, either for study or extermination.
There are those that attempt to harness the broadcasts with mundane means, such as cobbled together magi-tech radios. Thus making it so anyone with the right device can be a mage.
The Big Problem
With the blanketing of the world in a soup of radio waves (think TV, Radio, Bluetooth, WiFi, 3g, 4g, 5g, etc); the waves are interfering with each other. This leads to anomalies. Dangerous events and entities, that only the Coherers, and their understanding of broadcasts can stop.
So, The Plot
The characters are new coherers that are brought into this small society. Hunted by the anti-coherers, and dogged by intra-coherer politics.
Their main task is to get a handle on the anomalies.
But they also need to stop the development and distribution of the magi-tech radios.
They also try to stop the distribution of coherer technology (the magi-tech radios). They probably need to navigate intra-coherer politics.
Also, if the anomalies aren't stopped it might expose the whole premise or destroy the world.