In article , "quickhatch"
writes:

28636 kHz is a common clock frequency for some types of CPUs. Maybe you're
picking up the clock oscillator from somebody's nearby old Apple II or
something like that.

It can also be used as a NTSC or H-Synch clock for various TVs, VCRs,
DVDs, etc. Do a quick Google of 28.636 Mhz and you'll get tons of hits,
related both to CPU clocks and video synch signals.

Yep. 28.636 MHz is the 8th harmonic of 3.5795+ MHz, the NTSC color TV color
burst subcarrier frequency. Most early home computers (Apple II, Commodore 64,
Tandy Color Computer, Atari) used your TV as the monitor, and so the entire
computer was clocked at some multiple of the 3.58 freq.

Modern Nintendo, Sony, etc. game boxes probably follow the same rule, and since
every neighborhood has a few of these running, it's not surprising that you'd
get reports from all over the country, plus Canada, Latin America and I think
Japan, all using the NTSC system.
73, Mike K.

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