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FCC intentional/unintentional radiator

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jobbo

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Hi

In FCC's eyes, if a board with the onboard radio (e.g., Bluetooth) chip disabled by software, would it be considered to be an intentional or unintentional radiator? That is, the onboard radio chip is powered off by the firmware. There leaves a chance that someone hacks the firmware and enables the chip though.

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ftsolutions

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If your product isn't going to use the Bluetooth module, I don't know why you would incur the cost of the hardware to include it on the pcb?

Or, if you want to disable it in hardware, I would think one or two properly placed resistors in the interface/enable/reset lines could be added such that not stuffing them would prevent the unit from ever turning on, regardless of software.

If you are going to use the Bluetooth module, the product will have to be tested/certified.
 

SLK001

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An "intentional radiator" is a physical antenna. An "unintentional radiator" is something that radiates, but is not intended to. For instance, a battery, a trace, a display, a CPU, a charging cable, an accessory cable, etc, are not intended to radiate, but most of the time they do (unless properly designed to abate any radiators).

An intentional radiator can usually be "wholely contained", like removing the antenna and transmitting into a matched dissipating load. When this is done, the unintentional radiators will dominate the output spectrum. Hopefully, they will express themselves at levels below the FCC limits. If not, considerable effort might be needed to mitigate the radiators.

In my experience, the unintentional radiators are very difficult to mitigate, because the underlining design is "flawed". When they become apparent late in the design cycle, changes in the offending design is very much frowned upon and management pressures engineering for "quick fixes".
 

Warpspeed

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In EMC testing, the device needs to be configured in such a way that any or all options that may influence the test need to be taken into consideration.

If it has a Bluetooth chip and antenna installed, it must be tested with that option fully functional.
You can later disable it.
But if it is there it must become part of the test.
 

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