wmartin@brl-vgr.ARPA (Will Martin ) (04/19/84)
I just received a catalog from an electronic surplus and parts dealer (Chaney Electronics, Colorado) which contains an ad for a doohickey the likes of which I have never seen before. Here is the text of the description: NEAR ALARM -- Unique device made for the US Gov't to warn of nuclear attack. It was to be plugged into the wall outlet and sound off when power company switched from 60 to 50 cycles. An experimenter's delight! The case alone is well worth the price. C2706 $1.49 This is the first I have heard of the possibility of the power grid changing from 60 Hz to 50 Hz as part of an attack-warning mechanism. It seems a strange concept. I was under the impression that the power-line frequency was in some manner determined by the speed at which generators ran, so that changing the frequency would involve something much more elaborate than flipping a switch -- a coordinated effort over some time of slowing down generators and synchronizing different producers' output so that they were in phase, etc. In that case, I don't see how this switchover could be done within the seconds or minutes available after knowledge of an attack and before the alarm must be broadcast. Also, what would the purpose of such a change be? Just to set off these little alarms? The only "practical" effect I can imagine is that your electric clocks would all immediately slow down by 1/6th, thus giving you more time to run, pray, jump into shelters, or whatever... (-: Anybody have more info on this subject? It certainly seems odd... Will
spoo@utcsrgv.UUCP (Suk Lee) (04/20/84)
Lets face it: this is a gonzo device
for all those billyuns of gonzo people
out there.
On the subject of switching from
50 Hz to 60 Hz - NOOOOO!
Each power station is essentially
independant and keeps track of its own
line frequency, although there may
be co-ordinated effort between large
stations. Changing line frequencies
would be next to impossible--it would
have to be done VERY carefully to avoid
setting up instabilities in the power
grid, which can be modelled as a mess
of loosely coupled oscillators.
--from one who did a Bachelor's in
the subject (ICK!)
--
From the pooped paws of:
Suk Lee
..!{decvax,linus,allegra,ihnp4}!utcsrgv!spooedhall@randvax.ARPA (Ed Hall) (04/22/84)
+ I seem to remember reading about this in an old (~1960) Popular Electronics. The signaling mechanism was *not* changing the power frequency to 50hz, but was rather the introduction of harmonics of 60hz (3rd or 4th) onto the power grid. The level of this signal was only a few volts, and was produced by an arrangement of rectifiers and resonating circuits. (Changing the basic frequency of electrical power by 17% is essentially impossible, given the techniques used in power transmission.) The PE article showed a test of the device, with people releasing helium baloons when it sounded off. It mentioned how tests were made to insure that the signal didn't damage household appliances or industrial motors. I remember wondering about why it made any difference, and why anyone would even want to know of an attack... (I was quite young; this was before some people behind us put in a fallout shelter and before we started practicing `duck and cover' in school.) -Ed
hoffman@pitt.UUCP (04/24/84)
I wouldn't be a bit surprised i this wasn't just another of our government's little projects that went bust. I would guess that someone got this hotshot idea that the one common factor in everyone's office/home is electricity, and that could be used for signalling. An exorbitant amount of tax dollars were probably spent on this thing which, when completed, became a white elephant because no one thought to ask the power companies if they could change the frequency! I'd be curious as to how much this cost the government. No, on second thought, I'd rather not know. I'm still too depressed from April 15. :-( ---Bob Hoffman, Pitt CS -- Bob Hoffman
tac@teldata.UUCP () (04/26/84)
, (sop to the blank line eaters--consider it a religious sacrifice)
Do you suppose that the government knows something that we do not, and
that it is that the basis for Russian ICBM guidance relies on the power
grid in this country, and that by introducing this abberation at the
proper time they can cause all of the Russian missles to miss, and that
they do not want to announce this because the Russians would re-work
their guidance systems?? Lot of pretty big ifs there! Anyone got a
more plausable excuse?
"Governments never do anything by accident. If a government does something
you can bet that they intended to do it."
--FDR--
From the Soapbox of
Tom Condon {...!uw-beaver!teltone!teldata!tac}
A Radical A Day Keeps The Government At Bay.brad@ut-sally.UUCP (Brad Blumenthal) (04/30/84)
[]
Before we dismiss this too lightly, let's all take a moment
to remember conelrad (or however it's spelled -- I'm too
young to remember).
"Just below the police calls on your AM dial.
--
Take care,
Brad Blumenthal
{ihnp4,ctvax,seismo}\!brad\@ut-sally