982.002 MHz frequency indicates a likely human origin, since aliens or Mother Nature would not be sending an integer number of MHz.
But, as the article puts it, "suspiciously close". Except, I guess you'd accept .003 as close also. And, from the other side, you have .999, .998 etc. If you accept the range .995 to .005 as "close", that's already 11 values, so around 1 in 90 chance of hitting it at random.
Except, there might be other "suspicious" values. Like, .100, .200 etc. That gives us another 9. And then you could have things like .111, .222 etc.
If you accept around 50 different suspicious values of some sort then there's a 1 in 20 chance of hitting one at random. That doesn't seem so suspicious to me.
Its entirely possible someone out there (us, or ... them) has a nice magnetron (or more exotic tech) pumped main engine or station keeping thruster that uses microwave energy to boost exhaust temp and thus specific impulse.
Then given that as propulsion tech, its possible that a boring engineering specification like "make the nozzle two space alien foot lengths in diameter" which is a nice round measurement to a space alien, is in fact 982.blah MHz to our measurements.
Certainly no one cares that their terrestrial microwave oven operates at 2.45 GHz, all they know is it pops popcorn. And in a like manner, some microwave boosted propulsion system, either an earth or alien source, might just randomly end up on 982.blah MHz but the number means nothing to anyone, its just what fell out of the thruster design reqs. Say I was building a microwave pumped thruster, I'd make the nozzle less than a tenth wavelength at pump frequency to contain any leakage RF while letting white hot plasma stream out. 982.002 MHz would be 30.5 cm in a vacuum, so figure my engine nozzle diameter would be about 3 cm across for minimal leakage. You're probably not going to get a huge amount of thrust out of something 3 cm across, so its probably a station keeping thruster at most not some main acceleration thing. Besides a couple hours of thrust would imply going very fast if it was a main thruster but some minor course correction / station keeping thing could run a couple hours. So its entirely likely some space vehicle had a pretty substantial failure of a course correction thruster.
Another topic no one is willing to discuss, which is a bit weird, is the old fashioned superheterodyne topology works pretty well, so 982.002 MHz is not the frequency of operation, its something in a local oscillator chain of a receiver (or transmitter) that works somewhat above 1 GHz. Another "where are the EEs" comment is 982.002 is possibly not an INTENDED local oscillator output but someone's class B or class AB output stage had a single transistor failure and what was outputing a great low distortion signal at 491.001 is now outputing an icky harmonic signal at 982.002 or similar after the output section failure.
Just because the 15th harmonic of the FM sound carrier of an old fashioned analog low-band VHF tv transmitter on USA allocation channel 3 could fall less than 1% off from 982.002 but doesn't prove it is the source and probably is not, the point is we could be observing a failure mode or unintended interference.
Such civilizations would have a unit of time that’s a rational number of seconds. That would make such clashes possible (but very likely not likely, depending on how likely it is that a civilization uses caesium 133 as the basis for its clocks)
Of exactly 9192631770 Hz...