[time-nuts] Daft idea with the National Grid

[Fiorenzo Cattaneo]

I remember when studying covert channel communication (as part of computer
security) that during the cold war one of the ways you could transmit very
low bit rate data (1 bit per minute or slower) was by modulating the power
consumption of an industrial plant, something that a spy would be easily
able to do simply with a chronograph.
Presumably you would be able to do the same thing by modulating the
frequency of a generating power plant, for instance 49.99 Hz = 0, 50.01 Hz
= 1, or some frequency low enough that no equipment would ever notice,
unless you are actually looking out for this.

-- Fio Cattaneo

Universal AC, can Entropy be reversed? -- "THERE IS AS YET INSUFFICIENT
DATA FOR A MEANINGFUL ANSWER."

-----Original Message-----
From: time-nuts <time-nuts-bounces at lists.febo.com> On Behalf Of John
Moran, Scawby Design
Sent: Monday, 8 February, 2021 09:37
To: time-nuts at lists.febo.com
Subject: Re: [time-nuts] Daft idea with the National Grid

On Sun, 7 Feb 2021 20:45:57 -0800
Jim Lux said -


"If you happen to own something like a steel mill running electric

furnaces or an aluminum refinery, so you can manipulate the load..."

Sometime in the late '80s, my first decent sized computer system came on
line at a telecom factory in England. It ran fine for a few days then
crashed. Rebooting made it run fine for another 7 days then it crashed
again, and then every 7 days at almost the same time - like a very poor
clock. Monitoring the mains voltage with an expensive hired monitor showed
a huge drop in voltage lasting about ten seconds at the relevant time.

It turned out that the biggest steel rolling mill in Europe was only 5
miles away and they were testing new motors on the rolls. We had some
interesting visits and talks with them and persuaded them to turn the
motors on one by one instead of in batches and, in conjunction with some
hefty mains filtering, the problem went away.

That sort of load step must have been noticed by the electricity
suppliers, and half the computers in the city!

John

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