2.4 GHz Only
I believe that's a hardware limitation of the radio, which software won't be able to change.
I believe that's a hardware limitation of the radio, which software won't be able to change.
(This comment was inspired by this actually functional crazy project: https://web.archive.org/web/20220104163626/http://www.icrobo... | HN discussions: https://hn.algolia.com/?q=Pi+fm)
I wonder what a RPi 2040 could accomplish with its dedicated realtime components. Add a variable (center frequency and bandwidth) bandpass circuitry to filter out nasty harmonics and I'd guess you can at least go for purely software transmitting CW (morse code), FM and the various digital modes like DMR that are AFAIK all variations of either straight FM or FSK.
FPGAs are too expensive / require too niche knowledge to pull it off, and regular GPIOs suffer from hardware interrupts...
The other question of course is how to receive, but I guess for that you can use an RTL-SDR...
It's exceedingly unlikely to find something from the time of the psp in 2003/2004 that has 802.11a 5GHz and isn't a business laptop.
It was rare to find, but the networks were left weirdly open, presumably because it was rare, limited range, and they didn't care to troubleshoot security on top of connectivity.