The project page covers all of this, and takes the time to recommend various filtering strategies. It's not like this stuff is much worse than a faulty washing machine or hair dryer doing the same, or that the very same equipment under control of its official driver couldn't spew junk in exactly the same way
The device generates a comb of the original baseband, repeated all the way up to VHF.
There is no way that a simple passive filter will pick out the wanted signal, while blocking all the others.
It would take a sophisticated multi-stage active filter to even come close.
The "very same equipment under control of its official driver" won't have an amplifier and antenna connected to its output. If it did, it obviously would fail its EMC test approvals process.
> The "very same equipment under control of its official driver" won't have an amplifier and antenna connected to its output. If it did, it obviously would fail its EMC test approvals process.
Forgive me, but this seems quite a blanket statement to make of the tens-hundreds of millions of VGA cable and LCD/CRT designs and design combinations in deployment for the past 30+ years around the world, equipment combinations that never did (and never will) undergo system testing to verify there aren't, in fact, thousands+ of unintentional transmitters deployed already, by people who haven't a clue about their aberrant devices.
It's not like you can't buy dirt-cheap $5 unshielded ultra long VGA extender cables by the literal truckload off AliExpress and eBay, and that you don't find such cables strung vertically to 640x480 projectors hanging off the ceiling of just about every conference center, lecture hall, hotel business suite or similar meeting venue known to man.
Meanwhile this project is explicitly about creating a transmitter in an environment where it is understood by every user upfront the result could be noisy