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Comment by PhasmaFelis | Hacker News Reader

Thanks for the info, cbhl and paulmd. I'm afraid I still don't quite get it, probably because I don't understand EE and radio as well as I ought to.

Why is there significant expense in putting a ROM chip between the radio and the amplifier that cuts out certain frequencies? I can see where that's not as simple as mandating software that is simply incapable of generating bad frequencies in the first place, but it intuitively strikes me as the same sort of embedded programming that goes into, say, a microwave oven--I can see it adding some cost, but not so much that it would be unfeasible in e.g. an home wifi router. What am I not understanding?

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In hardware, $.15 is "significant expense" because the margins are thin and unit economics.

The list of blocked frequencies changes occasionally (like time zone definitions); if you can't update the "illegal frequency blocking" chip then it becomes illegal to use your otherwise-perfectly-good product once the rules change. Plus, it depends on what country you're in, so ideally if you move (or just go on a vacation) to another countries you don't want to have to throw away your old router/smartphone/smartwatch and buy new ones in the other country.

Chicken and Egg. If you can modify the radio (hardware/software), you can modify the protection device.

Adding a protection device merely shifts the problem (being discussed) from the radio to the protection device.

It achieves exactly nothing.

I'm not sure that follows. On the kind of wifi router that the FCC wants to ban, you can install new firmware because it's designed to allow you to to that. You could have accessible firmware whose signals have to pass through a non-accessible ROM.

You can change the frequency that a thing communicates on by changing the length of the wire in the antenna, and you can change the strength of the signal by changing the shape of the antenna, and the ROM will be none-the-wiser.

An example of the former is "homemade AM radio", where you wrap a lot of wire in a coil, and changing where you complete the the circuit along the coil allows you to "tune into" different frequencies.

An example of the latter is the cantenna, a directional antenna that can be made from a Pringles can.

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