Do hobbyist slabtop Wi-Fi modifications need to consult FCC regulations?
Do I need to consult FCC regulations in order to modify a laptop's internal WI-FI antennas to a new housing?
This is quite common when modifying laptops to "slabtops". For example, one could 3D print this sort of housing, and the place the IPEX-connected antennas in there:
https://www.printables.com/model/442588-screenless-macbook-pro-13-inch-early-2015-slabtop-
However, are these sorts of things technically appropriate as per FCC? They are modified designs after all. But is it possible that moving around laptop antennas does not change the specifications drastically, because, for example, the antennas are low-power or because the chassis does not play a significant part in the specifications?
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During FCC (or any other EMC) testing, the manufacturer will use some antenna(s) and only those antennas will be the ones approved. If you modify the antenna or use one which wasn't used in the test, then the item is no longer conforming.
Similarly, if a product's housing serves as signal/chassis ground (for an antenna or similar), then you can't change the housing either as that will affect the EMC approval.
Either way, a new EMC test is likely required.
I theory you could be facing fines if you modify a product like this and it ends up disturbing other approved devices. In particular if you are a commercial company putting modified products on the market.
FCC or equivalent authorities are probably not prioritizing chasing down hobbyists, but that too can happen. As an anecdote, this actually happened to me once. During development of a radio product, we purposely had it transmitting at larger power than allowed on the band and left it on day and night for logging/reliability testing. This eventually resulted in a sudden visit from black van with lots of curious antennas on top, belonging to the radio authorities - we had been jamming some poor soul in the same city trying to legally use that same frequency. They realized we were doing R&D work however, so they were quite understanding and we didn't get fined, but we had to dismantle our little test rig and promise not to be naughty again.
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is it possible that moving around laptop antennas does not change the specifications drastically, because, for example, the antennas are low-power
The radiated power is probably not low compared to what is allowed. Laptops with limited WiFi range don't sell well.
The limit could also be in the unintended frequencies. Even if the main power is "low", one or more unintended frequencies might be close to the limit.
or because the chassis does not play a significant part in the specifications?
The chassis and other stuff near the antenna may very well be part of what shapes the radiation pattern.
You don't know what effect various parts of the system have without testing the result of changing things. Simply moving a wire to bend one way instead of another can change things, especially in the unintended radiation bands.
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