I'd like to see about replacing the built-in antenna with an SMA pigtail or U.FL connector so I can a) locate the WiFi antenna well away from the Pi and b) put the Pi in a metal box (or wrap in foil) in order to contain as much RFI as possible without compromising WiFi connectivity.
Would it be possible to get enough of the schematic (and possibly PCB layout, if it's difficult to identify what's what) to see what sort of antenna is attached to the WiFi MAC and what passive RF loading components there are between the MAC and the white SMD antenna? (I assume that the MAC has a plain 50Ω RF I/O but that, because the antenna isn't quarter wave or dipole, there must be some passives to impedance match the antenna with the MAC unless the required matching is built-in to the antenna.)
I realise that this is a bit of a long shot given certification considerations etc, but it strikes me that it is better to get the information required to modify the Pi cleanly with minimal impedance discontinuities to avoid muddying the spectrum than to go it alone and make guesses, with possibly negative consequences to the local RF environment.
There are instructions out there for adding pigtails and even for adding an SMT U.FL connector (but out of deference for the Foundation and the mods of this forum, I won't link it unless I'm told it's okay to do so) but without knowing exactly what's there and what other modifications might be required, it's anybody's guess as to what results they'll produce. It'll probably work, but it might increase the local noise floor. I'd prefer to be a responsible RF citizen if possible
NB: I don't want to use a WiFi dongle because that would reduce bandwidth available to other devices (notably RTL-SDR dongles, possibly two or more if there's enough processing power), where the built-in WiFi is attached via SDIO. I don't need BlueTooth functionality so it's no bother if this mod compromises that.
Usual disclaimers acknowledged: mods done at own risk, warranty voided etc, and I indemnify the Foundation against liability for anything I might do with any information received.
Thanks,
David.
