Sonic is only in VERY SMALL PARTS of California. Basically scattered parts of the SF Bay Area and LA. Elsewhere, they might sell you plain DSL service (no voice, nothing else, 3 mbps tops) at a higher price than AT&T (though without some of the other hassles AT&T provides as extra added non-attractions).

California in general is like other places in the US: if broadband is available at all, there are no more than two providers (cable and phone co.) except for occasional fly-by-nights using odd technologies (variations on wireless, mostly, at higher prices than phone). Phone itself is either cell (which after Sprint is bought out by somebody will hit the 2 1/2 competitors point where competition effectively ends), or wired via cable or phone co. Small areas have independent phone companies or ISPs (like Sonic) that provide better or cheaper (seldom both) service. Google fiber is conspicuous by its absence in CA despite the Silicon Valley crowd.

There was a thread some time back that discussed antennas and TV. Basically, if the HOA won't let you have an antenna they are probably violating Federal law. Check it out with a lawyer.