Soon i will begin building an X86 build of openwrt preferably with Wi-Fi 7 capabilites. Ive been doing a lot of research for the past few days to get an understanding of the hardware support. Now if I understand this correctly, its universal that the most recommended thing is to use a separate router to connect to it since there's virtually no wifi cards that are avaliable to regular folks that perform anywhere near manafactured routers, am i correct on this?
My goal was to buy two PCiE wifi cards, one for 2.4 and one for the 5ghz ban (until i have enough devices supporting 6ghz). I'm getting mixed results on what might work with Openwrt. Im willing to put in the technical work to get it working, just trying to find the "most" compatiable card to start with.
Im also willing to forget it and do the separate router thing, i'm just trying to understand from Openwrt point of view the limitations vs native control. I'd imagine fine tuning things like power level and stuff is out the window. Any performance specific limitations or isolation problems possible?
I cannot comment about the drivers support and configurability for PCIE cards, but there are a few important reasons why a separate AP is generally recommended and almost always better for performance:
A purpose built AP will have a chipset and physical design that is optimized for AP use.
Compare this against many PCIE (or USB) cards which are generally designed to be used as clients (STA mode). Sometimes this means that chipset doesn't support simultaneous multi-band operation, and in certain cases AP mode may not be supported at all.
The purpose built AP will typically have an antenna system that is specifically designed for fairly isotropic wifi coverage (or in some cases it may have a specially designed pattern for specific applications), and then it can use advanced signal processing to beam-form based on the known and calibrated antenna positions. An antenna array on a PCIE card will not be nearly as controlled or advanced.
A PCIE card will generally have large metal obstacles (i.e. the PC's boards, power supply and chassis/case) that result in suboptimal and non-isotropic radiation patterns. By contrast, a purpose built AP will typically have a plastic case and the designers have accounted for the device's footprint in terms of the RF performance.
Especially for Wifi 6 and higher, the chipsets do tend to run warm/hot. A purpose built AP will have an appropriate thermal design to keep the chips operating within spec; a PCIE card may be difficult to cool, depending on the enclosure, airflow, and heatsink options.
For clarity, please call it a "separate AP" rather than a separate "router" -- the difference is that the AP is a bridge from ethernet to wifi, whereas a router is much more (i.e. routing). While you may actually use a device that is sold as a router and operate it in AP mode, there are also many good devices that are sold as APs (and not routers). It's also better when discussing your config to differentiate between the router and APs. But this is just a terminology thing.
given the economy of scale, a purpose built plastic wifi router/ AP tends to be cheaper as well (starting around 15-20 EUR, new/ delivered) - and you can place them in a suitable place.
most of these cards are out-of-spec in some regard, be it physical dimensions, heat dissipation (cooler is a must, fan recommended), current requirements at 3.3V (10 watts, per card), all of the above for most of them.
Apart from the issues mentioned above, what do you need to care of for buying AP-focused WLAN cards (plural):
at least 2 WLAN cards (and not the cheap/ client-focused ones) - or one DBDC capable one (but in that case, you'd really be better served by a cheap mt7621a+mt7915DBDC plastic router)
2 mini-PCIe or M.2 based adapters (as you are unlikely to find mainboards with two mini-PCIe or M.2 slots, unless you get really expensive; this also means at least µATX formfactor)
4-8 pigtails
4-8 antennas, for the corresponding frequency bands (good luck getting decent ones on the first try)