afc@shibaya.lonestar.org (Augustine Cano) (01/05/91)
I recently had a couple of quite dramatic power related experiences:
One day, while at the keyboard, I experienced dozens of brownouts over a
period of at least 45 seconds. All lights would dim for periods between
1/3 second and 1 second, the unix pc power supply would whistle and then
go back to normal. The system never crashed, even though I frantically
closed all windows, killed all processes and got ready for an orderly
shutdown.
On another occasion, the power went crazy; not in the orderly and
predictable fashion described above. This time the fluctuations were
completely random and even more serious. This also went on for at
least 30 seconds. Amazingly, I could hear explosions from outside,
perfectly synchronized with the power fluctuations. I thought a
transformer was about to blow up but everything went back to normal.
No crash this time either. It was a rainy day so I assume some wet
branch fell on the power lines and shorted them.
No damage occurred in either instance, possibly thanks to the very old
surge suppressor I have protecting the computer...
--
Augustine Cano INTERNET: afc@shibaya.lonestar.org
UUCP: ...!{ernest,egsner}!shibaya!afcwouk@alumni.colorado.edu (Arthur Wouk) (01/06/91)
on the other hand, my 3b1 (and my vcr) both went crasy during a very cold period during which i wore a lot of synthetics and generated a lot of static electricity. i got kernel parity errors just from brushing the keyboard (and my vcr clock stopped several times just from touching the case.) is this common in dry climates (near 0% humidity.)
gil@limbic.ssdl.com (Gil Kloepfer Jr.) (01/06/91)
In article <1991Jan5.045917.7018@shibaya.lonestar.org> afc@shibaya.lonestar.org (Augustine Cano) writes: [good luck in faring through a nasty brownout activity] >No damage occurred in either instance, possibly thanks to the very old >surge suppressor I have protecting the computer... The surge suppressor would not help protect you against brownouts, although it might help against any kind of surges resulting from power being restored in an indeterminent manner. Those surge suppressors are generally MOVs, which clamp high voltage spikes to ground, so that they don't ever get to your power supply, and possibly further. There are some more elaborate power supply strips which contain some power-line filters which help prevent RF from entering/leaving the machine through the power lines (the former can sometimes tell some chips to do funny dances). Both forms of protection are useful in many cases... A general word of caution though-- spike protectors are NOT lightning arrestors. The best protection from lightning is unplugging your machine from the power **AND** phone lines. There's an ongoing discussion in the 386 group about lightning damage through the phone lines. Most modems are terribly unprotected against such surges.... -- Gil Kloepfer, Jr. gil@limbic.ssdl.com ...!ames!limbic!gil Southwest Systems Development Labs (Div of ICUS) Houston, Texas "There are beautiful people I wish would have never opened their mouths, because such ugliness oozes out." Philosophy Prof. at NYIT
thad@cup.portal.com (Thad P Floryan) (01/06/91)
afc@shibaya.lonestar.org (Augustine Cano)
in <1991Jan5.045917.7018@shibaya.lonestar.org> writes:
[...]
On another occasion, the power went crazy; not in the orderly and
predictable fashion described above. This time the fluctuations were
completely random and even more serious. This also went on for at
least 30 seconds. Amazingly, I could hear explosions from outside,
perfectly synchronized with the power fluctuations. I thought a
transformer was about to blow up but everything went back to normal.
[...]
You SURE you don't live in my neighborhood? :-) The power pole out in my
backyard has a habit of spontaneously spitting flames, incredible sparks
running up and down the WOOD pole (who said wood was nonductive? not in
California it ain't! :-), and otherwise being a general nuisance.
UPS and surge protection for all my systems are the only reasons my systems
are still "alive" today. Seriously. I've posted some real horror stories to
some other newsgroups, the worst being when one surge protector burst into
flames and I grabbed it and tossed it out the window ... what caused this
was the power service suddenly experienced an "open neutral" according to
PG&E, causing some 250V+ to be on the lines instead of the nominal 120.. I
proved "negligence" on the part of PG&E and received full $$$ replacement to
buy new protection; point being, NONE of my computers or other electronic
equipment were affected; the surge protector DID work by suiciding and saving
everything else. I shed a tear and gave it a decent burial.
Other cases prior to my "getting smart" and getting surge and UPS protection,
not so dramatic, include disk R/W errors caused by such "innocent" things as
refrigerator kicking in, turning on/off flourescent lamps, operating a drill
motor in my garage, turning a modem on/off, etc.
In ALL seriousness, if you're NOT operating with at least surge and transient
suppression on the line servicing your computer(s), you're asking for trouble.
And do NOT scrimp on quality to save a few bucks, you'll be sorry. I had put
out bids to several local companies for surge/transient suppression and UPS
protection and learned some interesting things.
For one thing, Radio Shack surge protectors are simply junk. We opened one
up and compared it to the ones I finally bought(GTE); difference was like that
between night and day. I also put GTE suppressors on my phone lines to
parallel the lightning arrestors supplied by PacBell. Another thing I learned
was that some surge and transient "suppressors" are so poorly enginerred (sic)
they actually MULTIPLY the incoming spikes! The only saving grace with those
(bad ones) was that you'll never get over 4,000 volts coming into your system
because the distance between the prongs on a conventional AC plug is the spark
gap for 4,000 volts!
As for UPS systems, I got the (sine wave) ones from SAFE (which, by the way,
are also the ones used by Convergent ... I didn't know this at the time).
Thad Floryan [ thad@cup.portal.com (OR) ..!sun!portal!cup.portal.com!thad ]thad@cup.portal.com (Thad P Floryan) (01/06/91)
jfischer@cbnewsm.att.com (james.fischer)
in <1991Jan6.043817.13755@cbnewsm.att.com> writes:
[...]
Of course, if your try this at home, put your surge protection
in on the UTILITY side of the CVT!!!
Good advice!
As an aside, is "osu-cis" the archive server used by this group?
(I am new to this newsgroup...)
Can one ftp from it?
What is the address?
"osu-cis" is one of the primary archive sites for 3B1/UNIXPC/PC7300 material.
If you "do" ftp, the specific site you want is cheops.cis.ohio-state.edu
[IP 128.146.8.62] and the relevant path is ~ftp/pub/att7300 (which has one
subdirectory, /STORE, for material that used to reside at AT&T's "The STORE!").
The other "interesting" osu-cis site is tut.cis.ohio-state.edu
[IP 128.146.8.60] at which you'll find all the GNU/FSF material as would be
found at MIT.
uucp access to osu-cis appears in the monthly "FAQ" for this newsgroup.
Also, at least one person has stated intent to set up a 3B1 system in
California shortly to serve the west coast as an archive site. Details will
be posted as they become available, and there "may" be a slight subscription
fee to defray operating expenses (phone, power, AC line prot., backup media,
etc.). I'll relay any info I get in this regards, and, no, it won't be at my
site since I'm having a difficult enough time just getting the phone lines I
need, let alone an extra one for public access.
It's possible, too, that if/when we get the Silicon Valley AT&T Users' Group
incorporated that AT&T may "help" us out setting up a uucp site as they did
the Silicon Valley Computer Society.
Thad Floryan [ thad@cup.portal.com (OR) ..!sun!portal!cup.portal.com!thad ]thad@cup.portal.com (Thad P Floryan) (01/06/91)
wouk@alumni.colorado.edu (Arthur Wouk) in <1991Jan6.050124.6838@csn.org> asks: on the other hand, my 3b1 (and my vcr) both went crasy during a very cold period during which i wore a lot of synthetics and generated a lot of static electricity. i got kernel parity errors just from brushing the keyboard (and my vcr clock stopped several times just from touching the case.) is this common in dry climates (near 0% humidity.) Yes. And also during the winter months in buildings with forced-air heating. In my office computer center we even have a controlled-humidifier to maintain approx. 55% RH. If the RH drops below 30%, one gets static shocks off the computers' chassis. Static is NO GOOD for computers, and can destroy sensitive parts. And for those electronics hobbiests amongst you, don't play with Tesla coils within 400m (1/4 mile) of computers ... you WILL zap CMOS ICs. This is NOT a joke. Considering that you can "light" 120VAC lamps 20 feet away from a Tesla coil, think what broadcast electricity (so to speak) does to ICs; the disaster occurs within the first milliSecond of firing up the coil, and the present thinking is the effect is similar to the EMP (Electro-Magnetic Pulse) during a nuclear blast. I know I'm probably going to get "flamed" for mentioning that aspect of Tesla coils (re: computer terrorism), but I feel the message must go out. Thad Floryan [ thad@cup.portal.com (OR) ..!sun!portal!cup.portal.com!thad ]
floyd@ims.alaska.edu (Floyd Davidson) (01/06/91)
In article <1991Jan6.050124.6838@csn.org> wouk@alumni.colorado.edu (Arthur Wouk) writes: >on the other hand, my 3b1 (and my vcr) both went crasy during a very >cold period during which i wore a lot of synthetics and generated a >lot of static electricity. i got kernel parity errors just from >brushing the keyboard (and my vcr clock stopped several times just >from touching the case.) > >is this common in dry climates (near 0% humidity.) In one word: yes. The lower the temperature the less water vapor the air is able to hold, hence, lower relative humidity as the temp goes down. Less humidity causes more problems with static electricity. There are several things that can be done to reduce the effects: 1) Increase the humidity (humidifier, boil water on the stove, etc.) 2) Don't where synthetics. 3) Place metal grounding plates, straps, etc. where useful. 4) Spray rugs etc. with an anti-static solution. Be careful with the idea of grounding plates etc. They should NOT be directly grounded. About 5Mohms is right I think (but not positive). My computer desk has a metal (aluminum) piece of trim along the front that my arms rest on everytime I relax at the keyboard. It is grounded through several 1 Meg Ohm resisters in series. There are many suitable anti-static solutions. You can buy one labeled as such and pay for the label. You can use something like 409 cleaner (that is what I use) diluted. Or go to a photo store and buy a small bottle of FotoFlow. Floyd -- Floyd L. Davidson floyd@ims.alaska.edu Salcha, AK 99714 paycheck connection to Alascom, Inc. When I speak for them, one of us will be *out* of business in a hurry.
dt@yenta.alb.nm.us (David B. Thomas) (01/07/91)
gil@limbic.ssdl.com (Gil Kloepfer Jr.) writes: >The best protection from lightning is unplugging your machine from >the power **AND** phone lines. My friend Mark (no credentials at all) reports that tying your cords in knots actually helps protect the equipment against lightning. He said he sustained an actual hit to his power lines, and the cord caught fire, but the equipment, which was plugged in, was unharmed. My first thought was to balk....but consider this: The knots form inductors which have a fairly large reactance at rf. Lightning has lots of rf energy (switch on a radio during a thunderstorm to prove this!). So... a knot looks to lightning like an inductor with non- negligible inductance, and it will absorb some of the energy before the equipment gets any. To be honest, I haven't taken any of this seriously enough to have tied all my cords in knots yet, but hey --- it's probably worth a try. I'd trust it no less than a box that costs $1000 and says "lightning eliminator" on it! :-) little david -- In electronics, no one thinks you're strange if you blow your pal.
floyd@ims.alaska.edu (Floyd Davidson) (01/07/91)
In article <1991Jan7.084738.7441@yenta.alb.nm.us> dt@yenta.alb.nm.us (David B. Thomas) writes: >gil@limbic.ssdl.com (Gil Kloepfer Jr.) writes: > >>The best protection from lightning is unplugging your machine from >>the power **AND** phone lines. Good advice. >My friend Mark (no credentials at all) reports that tying your cords >in knots actually helps protect the equipment against lightning. >He said he sustained an actual hit to his power lines, and the >cord caught fire, but the equipment, which was plugged in, was >unharmed. First off, what is a direct hit? Well a real direct hit involves on the order of 100,000 to 300,000 amps of current at its peak. NOTHING will protect you from that. And it would melt even the power line, never mind the telphone line. Actually what we all get hit with is the current induced indirectly into power or telephone lines. The spectrum (frequency range) for the energy that comes into your house on the power or tel lines depends on how good a transmission line and how far the current has to travel. By the time it gets to your equipment there probably has been quite a bit of rolloff in the upper frequency ranges due to the simple fact that neither power or tel lines are designed to be used at anything other than relatively low frequencies. Not that higher frequency components won't be there, just that they will have been attenuated to some degree that will vary depending on a number of things, including the distance involved. There is a difference whether it comes from down the road a couple miles or if it is in your backyard. > >My first thought was to balk....but consider this: > >The knots form inductors which have a fairly large reactance >at rf. Lightning has lots of rf energy (switch on a radio >during a thunderstorm to prove this!). Two problems: 1) it really is a very low reactance, and 2) the higher ranges of rf energy may or may not be what comes down the line. One tight turn in your tel line modem cord does not have even the inductance of say a half mile of cable. Several turns doesn't either. >So... a knot looks to lightning like an inductor with non- >negligible inductance, and it will absorb some of the energy >before the equipment gets any. > >To be honest, I haven't taken any of this seriously enough >to have tied all my cords in knots yet, but hey --- it's >probably worth a try. I'd trust it no less than a box >that costs $1000 and says "lightning eliminator" on it! :-) > All it would do is very slightly attenuate what has already been attenuated the most. Three or four turns might affect frequencies above say 100 Mhz a little and above 200 Mhz a lot. I'm not sure what range is most common, or most damaging. But I'm sure it is lower than that. If you do want to do something along these lines, wrap a couple turns through a high Q toriodal core. I don't know if it will help with lightning protection, but it sure will help cut the rf radiation from your computer down! Floyd -- Floyd L. Davidson floyd@ims.alaska.edu Salcha, AK 99714 paycheck connection to Alascom, Inc. When I speak for them, one of us will be *out* of business in a hurry.
bruce@balilly.UUCP (Bruce Lilly) (01/07/91)
In article <1991Jan6.103604.13477@ims.alaska.edu> floyd@ims.alaska.edu (Floyd Davidson) writes: > >The lower the temperature the less water vapor the air is able to hold, >hence, lower relative humidity as the temp goes down. Less humidity >causes more problems with static electricity. Just a small nit: It is possible (and not uncommon) to have low temperature and high relative humidity. However, given some amount of water vapor, the *relative* humidity will decrease as the air (+ water vapor) is heated. (If the temperature then goes down, the RH will again increase) During cold weather, indoor air is generally heated, causing the relative humidity to decrease unless water vapor is added as the air is heated. The greater the differential in indoor/outdoor air (assuming ventilation is adequate, and the outdoor air is what is being heated), the lower the relative humidity will be (for a given outdoor RH) failing any humidification of the heated air. -- Bruce Lilly blilly!balilly!bruce@sonyd1.Broadcast.Sony.COM
dave@das13.snide.com (Dave Snyder) (01/08/91)
In article <37644@cup.portal.com>, thad@cup.portal.com (Thad P Floryan) writes: > And for those electronics hobbiests amongst you, don't play with Tesla coils > within 400m (1/4 mile) of computers ... you WILL zap CMOS ICs. > Whoa! Is this really TRUE? What about negative ion generators? What about those new "gas plasma" balls? DAS -- David A. Snyder @ Snide Inc. - Folcroft, PA UUCP: ..!uunet!trac2000!das13!dave INTERNET: dave@das13.snide.com
thad@cup.portal.com (Thad P Floryan) (01/08/91)
dave@das13.snide.com (Dave Snyder) in <1470@das13.snide.com> writes: In article <37644@cup.portal.com>, thad@cup.portal.com (Thad P Floryan) writes: > And for those electronics hobbiests amongst you, don't play with Tesla > coils > within 400m (1/4 mile) of computers ... you WILL zap CMOS ICs. > Whoa! Is this really TRUE? What about negative ion generators? What about those new "gas plasma" balls? Negative ion generators are OK, and, in fact, work well to reduce the problem at the front of CRTs (high concentration of positive ions which attracts all the various atmospheric contaminants and suspensions such as stale farts, smoke, etc.). No fooling'! In fact, we had one employee at my company who liked to use a terminal whose keyboard was right up against the CRT ... and her hands would develop a horrible rash on the topside until we focussed a negative ion generator at the front of her CRT. The bad effect of negative ions is that too MANY will upset the balance the OTHER way and cause dirt and crap to precipitate out onto one's walls, desks, chairs, etc. ``"gas plasma" balls'' ... dunno. But a Tesla coil is DESIGNED to induce volts into the surrounding environment and WILL zap computers. You should read the history of N. Tesla. He and Edison feuded long and hard; Edison was deathly afraid of the AC transmission power which Tesla advocated. Tesla won out, and we now have AC power distribution in this (and other) country(ies). Edison favored DC power transmission. Perhaps he was "right", since now there's growing concern that low frequency AC power transmission causes all sorts of ailments, mental disorders and possibly cancer. Tesla liked to make artificial lightning. He'd have been a "natural" for working on the SDI ("Star Wars") program! :-) And one of Tesla's great projects was "broadcast power" ... transmission of power through the "ether" to power everything WITHOUT all the high-tension power lines. And with a Tesla coil I could destroy EVERY electronic device in your home and on your person from a van parked out in the street. Computers, digital watches, VCR, AM/FM radio, computerized thermostat, cellular telephone, etc. are all susceptible. Scary, huh? z-z-z-z-ZAP! *P*O*W* :-) Thad Floryan [ thad@cup.portal.com (OR) ..!sun!portal!cup.portal.com!thad ]
pete@nyet.UUCP (Pete Hardie) (01/09/91)
In article <1991Jan6.103604.13477@ims.alaska.edu> floyd@ims.alaska.edu (Floyd Davidson) writes: >There are many suitable anti-static solutions. You can buy one >labeled as such and pay for the label. You can use something like >409 cleaner (that is what I use) diluted. Or go to a photo store >and buy a small bottle of FotoFlow. A good idea is to use somewhat diluted fabric softener, if it's one of the brands that will reduce 'static cling'. We used it at a previous job when static charges kept causing resets every time we touched the tape drive. You spray it on the carpet to prevent buildup while walking. Those dryer sheets are rumors to work well, too. -- Pete Hardie mail: ...!emory!stiatl!slammer!nyet!pete "Well, Darkness has a hunger that's insatiable, And Lightness has a call that's hard to hear" -- Indigo Girls
pete@nyet.UUCP (Pete Hardie) (01/09/91)
In article <134@limbic.ssdl.com> gil@limbic.ssdl.com (Gil Kloepfer Jr.) writes: >Both forms of protection are useful in many cases... A general word of >caution though-- spike protectors are NOT lightning arrestors. The >best protection from lightning is unplugging your machine from the power >**AND** phone lines. There's an ongoing discussion in the 386 group >about lightning damage through the phone lines. Most modems are terribly >unprotected against such surges.... Indeed. I have a modem that was fried when some spike travelled up the phone line. My roommate had been on when the storm arrived, and he was smart enough to unplug the power cords, but didn't think about the phone cords. Considering that my grandmother has a friend who was nearly deafened by her phone when lightning struck nearby, I marvel that any phone devices last as long as they do. -- Pete Hardie mail: ...!emory!stiatl!slammer!nyet!pete "Well, Darkness has a hunger that's insatiable, And Lightness has a call that's hard to hear" -- Indigo Girls
neal@mnopltd.UUCP (01/09/91)
->And with a Tesla coil I could destroy EVERY electronic device in your home
->and on your person from a van parked out in the street. Computers, digital
->watches, VCR, AM/FM radio, computerized thermostat, cellular telephone, etc.
->are all susceptible.
It better be an OLD van, or you will fry yer own ignition system...
------------------------------------------------------------------------------
Neal Rhodes MNOP Ltd (404)- 972-5430
President Lilburn (atlanta) GA 30247 Fax: 978-4741
emory!mnopltd!neal
gatech!emory!mnopltd!neal
------------------------------------------------------------------------------dt@yenta.alb.nm.us (David B. Thomas) (01/09/91)
thad@cup.portal.com (Thad P Floryan) writes: >And with a Tesla coil I could destroy EVERY electronic device in your home >and on your person from a van parked out in the street. Computers, digital >watches, VCR, AM/FM radio, computerized thermostat, cellular telephone, etc. >are all susceptible. Please, Thad! I already had one bad dream about zapping my poor 3b1 motherboard last night. Now I'm really gonna sleep badly! I heard that Edison was so vehemently opposed to Tesla's AC that he staged a demonstration on "The Effect of AC on This Dog". It wasn't pretty. So how big, physically, would this destructive device be? And would you simply zap it in the vicinity, and the massive EMI will do in sensitive equipment? Are our military's electronic items susceptible as well? little david -- In electronics, no one thinks you're strange if you blow your pal.
afc@shibaya.lonestar.org (Augustine Cano) (01/10/91)
In article <134@limbic.ssdl.com> gil@limbic.ssdl.com (Gil Kloepfer Jr.) writes: >In article <1991Jan5.045917.7018@shibaya.lonestar.org> afc@shibaya.lonestar.org (Augustine Cano) writes: >[good luck in faring through a nasty brownout activity] >>No damage occurred in either instance, possibly thanks to the very old >>surge suppressor I have protecting the computer... > >The surge suppressor would not help protect you against brownouts, although >it might help against any kind of surges resulting from power being >restored in an indeterminent manner. Those surge suppressors are generally Yes, of course. Obviously the brownout resistance rests exclusively with the unix pc power supply and the reserve power accumulated in the caps. The high pitch noise that occurred during the brownout periods probably just means that the switching circuits had to work extra hard to maintain the output voltage. Any power supply experts out there care to explain in detail this phenomenon? > [ extra info about surge suppressors & lightning arrestors deleted ] > >-- >Gil Kloepfer, Jr. gil@limbic.ssdl.com ...!ames!limbic!gil >Southwest Systems Development Labs (Div of ICUS) Houston, Texas >"There are beautiful people I wish would have never opened their mouths, >because such ugliness oozes out." Philosophy Prof. at NYIT -- Augustine Cano INTERNET: afc@shibaya.lonestar.org UUCP: ...!{ernest,egsner}!shibaya!afc
dmk@dmk3b1.UUCP (David Keaton) (01/10/91)
In article <37644@cup.portal.com> thad@cup.portal.com (Thad P Floryan) writes: > >And for those electronics hobbiests amongst you, don't play with Tesla coils >within 400m (1/4 mile) of computers ... you WILL zap CMOS ICs. True. Back in high school we had a PDP-11/40. A physics class meeting in a nearby classroom fired up a Tesla coil and blew a chunk of our memory. The chips had holes burned in them and were literally smoking. On a related note, I have an electrostatic precipitator (air cleaner, not an ion generator) at home. Every once in a while, it arcs 6000 volts across its plates. It used to crash an old Osborne-1 I had until I ran an extra ground cable from the keyboard to the main unit. It has never bothered my 3b1, though. David Keaton uunet!dmk3b1!dmk
mco@slimer.UUCP (Mark C. Otto) (01/10/91)
In article <1991Jan7.124138.19055@ims.alaska.edu> floyd@ims.alaska.edu (Floyd Davidson) writes: > [ ... lots of good stuff deleted ... ] >If you do want to do something along these lines, wrap a couple >turns through a high Q toriodal core. ... Yes! I have seen coils used effectively with MOV's (per Gil's mention earlier) to provide reasonable amounts of protection at low cost. If you want to see how things can go awry, read Jerry Pournelle's "Chaos Manor" column in Byte Magazine ... uh ... oops! I forgot the issue ... uh, suffice it to say a lightning strike took out a high voltage line and put it squarely in contact with the 220V feed to his neighborhood. He details the types of protection he had and what types of stuff survived and what didn't. In general MOV/coil circuits handle lightning strikes if they are several miles away or on the other side of a step-down transformer. More serious stuff - like what happened to Mr. Pournelle - can only be dealt with properly via an UPS, preferably with an isolation transformer and a good over-voltage trip circuit. I feel good power protection is like buying insurance for your computer - you can go without it, but the downside risk can have devastating potential. -- Mark C. Otto EMail: mco@slimer, {teemc | hpftc}!slimer!mco Voice: 1-313-441-4264 USnail: 5133 Heather #208, Dearborn, MI. 48126 Quote: "Yeah. Right. Kermit my a*s." - Mark C. Otto, '90
thad@cup.portal.com (Thad P Floryan) (01/10/91)
neal@mnopltd.UUCP in <164@mnopltd.UUCP> writes:
->And with a Tesla coil I could destroy EVERY electronic device in
->your home and on your person from a van parked out in the street.
->Computers, digital watches, VCR, AM/FM radio, computerized thermostat,
->cellular telephone, etc. are all susceptible.
It better be an OLD van, or you will fry yer own ignition system...
How true. Even high-power RF energy will temporarily "disable" the ignition
systems and computers on modern vehicles.
I was driving down I-280 in Silicon Valley when along comes a "rubber ducky"
running what I believed to be a 1000W linear amp (for CB) in his vehicle when
everything, that's EVERYTHING, in my car ceased functioning and the dashboard
totally lit up until the #^$(*!&^ idiot passed on by. Even my wrist-watch
was affected, going into a weird state until I pulled the battery and reset it.
That was one of the few instances where, if sufficient weaponry was onboard,
I would have blown that vehicle and its driver out of existance. Seriously.
Of course, the electronics in my car "should" have been better shielded. As
it is, nearly everything from dual fuel pumps to gas flow meter, etc etc is
connected with unshielded cabling. (yeah, a few years ago I decided to buy a
vehicle that's almost like a "fly by wire" jet fighter).
Just imagine what would have happened to some pedestrian with a heart pacemaker
or other electronic "appliance."
Sheesh. RFI pollution is NO joke; it can be a matter of life or death. That's
why it's illegal.
And a Tesla coil can do so much more ...
Thad Floryan [ thad@cup.portal.com (OR) ..!sun!portal!cup.portal.com!thad ]thad@cup.portal.com (Thad P Floryan) (01/11/91)
dt@yenta.alb.nm.us (David B. Thomas)
in <1991Jan9.064342.7045@yenta.alb.nm.us> writes (re: Tesla coils):
So how big, physically, would this destructive device be? And
would you simply zap it in the vicinity, and the massive EMI
will do in sensitive equipment? Are our military's electronic
items susceptible as well?
I haven't studied Tesla coils all that much, but the dealer from whom I
bought my surge protectors and UPS systems has a neato mobile display which
he takes to customer sites and part of the display is a Tesla coil that
weights about 40 pounds and is about the size of a small kid ... it has been
known to zap IBM-PCs in adjacent rooms (no great loss, right! :-) He has
stopped using that Tesla coil due to requests from his insurance company.
A big concern should there ever be a nuclear war is that the EMP would take
out the entire telephone system, all computers, all radios, all radar, traffic
lights, etc etc etc so my answer would be "Yes, our military's electronic
items are susceptible as well."
And do NOT bring up "Tempest" shielding; that's only to prevent RFI emissions
FROM military equipment being detected, intercepted and decoded. One of the
original requirements for DES was simply to "protect" data travelling on wires
between a CPU and its peripherals ... those RFI emissions CAN be detected and
sensitive info so broadcast can be picked up and used by spies and competitors.
Even the RFI hash from the front of a CRT can be relatively-easily "decoded"
and an exact image of a CRT, say, 100 feet away, can be reconstructed on
another CRT; in other words, your sensitive spreadsheet info on your screen
in a closed room can be "intercepted" (by picking up the RFI) and displayed on
another CRT.
Operating a computer in something like a Faraday Cage may serve to reduce the
effects of the "problems" mentioned above. I remember back when I worked for
the Electronic Defense Labs how we HAD to use such shielded rooms just to be
ablse to measure some of the things we were doing ... other equipment in the
lab ('scopes, voltmeters, etc.) would otherwise interfere our measurements
(and this was back in the early '60's).
I would venture to speculate that all such problems can be solved if one is
willing to spend enough money and endure the concomitant inconvenience(s).
Sorta like the goal of "security" is to make it cost more in time and effort
than the breach is worth, one has to make a decision as to how much the peace
of mind is worth; and locks can only keep out "honest" people, not a thief! :-)
Thad Floryan [ thad@cup.portal.com ]res@colnet.uucp (Rob Stampfli) (01/11/91)
>And for those electronics hobbiests amongst you, don't play with Tesla coils >within 400m (1/4 mile) of computers ... you WILL zap CMOS ICs. I am a ham radio operator. I have gone to numerous hamfests where various individuals were actively operating tesla coils in order to garner interest in a potential sale of tesla coil kits. Now, I always carry a handheld ham radio transceiver with me. It is like a walkie-talkie, complete with tuned circuits, ICs, a control microprocessor, and even a rubber duck antenna. I must admit I was and am quite leary of these active displays, but I have never suffered a burned out radio because of it, and I have never known anyone who has. Many of the observers are carrying hand-helds literally within feet of the tesla coil. In the same building, there is usually someone hawking computers. I don't dispute that it is possible to zap a computer with a tesla coil, but why doesn't their use at these hamfests cause a major catastrophe? -- Rob Stampfli, 614-864-9377, res@kd8wk.uucp (osu-cis!kd8wk!res), kd8wk@n8jyv.oh
thad@cup.portal.com (Thad P Floryan) (01/11/91)
res@colnet.uucp (Rob Stampfli) in <1991Jan11.025038.11661@colnet.uucp> writes: >And for those electronics hobbiests amongst you, don't play with Tesla >coils within 400m (1/4 mile) of computers ... you WILL zap CMOS ICs. I am a ham radio operator. I have gone to numerous hamfests where various individuals were actively operating tesla coils in order to garner interest in a potential sale of tesla coil kits. [...] I don't dispute that it is possible to zap a computer with a tesla coil, but why doesn't their use at these hamfests cause a major catastrophe? Probably because the HAMs would jam the remnants of their handheld transceivers down the throat of any clown with a really *B*I*G* Tesla coil! :-) Seriously, as with most other things, there are power differences amongst different models. Contrast a SONY Walkman to a 1000W Phase Linear audio amp. Contrast a gas-operated leaf blower to the engine on the Space Shuttle. Contrast a precision micro soldering pencil to a 500W soldering gun. I've seen small, desktop (literally handheld) Tesla coils, and I've seen Tesla coils from which I want to be more than a mile away when energized. And Popular Science had a picture of one circa 1980 that was over 75 feet tall ... I don't even want to be in the same country when THAT one is fired up! The one the dealer had (re: surge suppressors and UPS systems) was about 4-1/2 feet tall (chest-high to me), and his insurance company "convinced" him not to energize it any more at demonstrations due to claims of damaged computers. We did fire it up "one last time" in his parking lot; neat! It's since been dismantled. High power "anything" will "do in" things. I recall one incident that is "rumored" to have occured either at Ft. Bliss TX (Air Defense School) or at White Sands Missile Range circa late '50s or early '60s: a soldier took a shortcut through the "beam" in a multi-megawatt RADAR installation and keeled over, and it wasn't apparent what happened until after the autopsy: certain internal organs were cooked. This incident is "rumored" to have been the start of what we today know as MicroWave ovens. Though I was there at the time, I don't have any first-hand information, but I also have NO reason to disbelieve such an incident did occur. The frequencies used in consumer-grade ovens "like" objects the size of eyeballs and human testicles which is one of the reasons why, to this day, I still don't have a microwave oven at home. And before you pshaw-away my "fears", remember that one of my specialties is microwave engineering with which I was gainfully employed at the Electronic Defense Labs until I got involved with computers and a small "startup" known as Tymshare Associates whose legacies today are Tymnet (now owned by British Telecom) and McDonnel-Douglas Field Service Operations. One final comment: power decreases with the square of the distance, which is probably why a small Tesla coil at your HAM-fests doesn't perturb the other equipment. Even those huge electro-magnets that are used to lift cars have little power to do so with just an inch or two separation (but, again, the EMP-like effect of a Tesla coil cannot be compared to magnetism). Thad Floryan [ thad@cup.portal.com ]
templon@copper.ucs.indiana.edu (jeffrey templon) (01/12/91)
In article <37881@cup.portal.com> thad@cup.portal.com (Thad P Floryan) writes: >White Sands Missile Range circa late '50s or early '60s: a soldier took a >shortcut through the "beam" in a multi-megawatt RADAR installation and keeled >over, and it wasn't apparent what happened until after the autopsy: certain >internal organs were cooked. This incident is "rumored" to have been the Yeah, this is a problem. I got interested in Solar Power Satellites at one time and did some research. This was one of the worries - for those baffled, an SPS is a big satellite with solar panels, converts sunlight to electricity and then beams it down to earth in microwave form - that if somehow the guidance got screwed up, there would be this swath of destruction cut by the wandering power beam. Even if it did stay on target, they would be forever collecting birds and small rodents which died near the receiving antennas. Maybe we should rename the new group to comp.sys.3b1.boom.boom.boom ! Jeff
ignatz@chinet.chi.il.us (Dave Ihnat) (01/12/91)
In article <517@nyet.UUCP> pete@nyet.UUCP (Pete Hardie) writes: >In article <1991Jan6.103604.13477@ims.alaska.edu> floyd@ims.alaska.edu (Floyd Davidson) writes: >A good idea is to use somewhat diluted fabric softener, if it's one of the >brands that will reduce 'static cling'. We used it at a previous job when >static charges kept causing resets every time we touched the tape drive. >You spray it on the carpet to prevent buildup while walking. Heh. I remember once, back in about '81, I was on a contract at Bel--er, a Large Telecommunications Company in Naperville, and we were undergoing such a burst of growth with the project I was on that our lab was in a *carpeted* room. We were building a "portable" Unix 3.0 8086 for field testing--dubbed the FTS, for Field Test Set (catchy, huh?) and always had the guts out for ROM and RAM swaps, mods, etc. Static got so bad that we had to do something; so we kept a can of "Cling Free" by the door, and *every time* anyone walked in the lab, they had to liberally dose themselves with the stuff to protect the equipment. I still hate the smell of Cling Free... Dave Ihnat ignatz@homebru.chi.il.us (preferred return address) ignatz@chinet.chi.il.us
dwn@swbatl.sbc.com (David Neill-OKCy Mktg 405-278-4007) (01/12/91)
As an aside to this discussion, I lost my power supply (3b1, 245W) to a series of power dropouts (about 8 times in 30 seconds) last weekend. The system has a decent surge protector, and has survived dozens of power drop-outs before, but none (that I know of) where the power came back on and went back off that many times in such a short period. I was in another room, and by the time I got to the 3b1, it was too late. Anyway, before bringing it back up (with new power supply), I got a commercial power relay (16 amps!), and wired the power to the relay coil through the contacts of the relay. This way, when the power drops once, the relay contacts open, and no more power flows to the machine until I manually reset the relay. This contraption is connected to the wall socket, in front of everything else. At least I won't get this kind of "series hits" in the future. I call this thing a "power interrupt safety switch", and am thinking of marketing it... "Commercial power problems? PISS on it" :-) A UPS would be ideal, but somehow, there's always a higher priority for my limited funds. I fixed the boot-up procedure to prevent "fsck -y" some time back, and thankfully, the disk was ok. (Thanks, Lenny) -- name & address (this account) -> uunet!swbatl!dwn OR dwn@swbatl.sbc.com David Neill office -> 405-291-1990 -> uunet!swbatl!oktext!mktco Mgr - Mktg.(SWBTCo) home -> 405-843-4464 -> uunet!swbatl!oktext!frodo!david
thad@cup.portal.com (Thad P Floryan) (01/14/91)
dwn@swbatl.sbc.com (David Neill-OKCy Mktg 405-278-4007)
in <1991Jan12.155433.11110@swbatl.sbc.com> writes:
[...]
Anyway, before bringing it back up (with new power supply), I
got a commercial power relay (16 amps!), and wired the power to
the relay coil through the contacts of the relay. This way,
when the power drops once, the relay contacts open, and no more
power flows to the machine until I manually reset the relay.
This contraption is connected to the wall socket, in front of
everything else. At least I won't get this kind of "series hits"
in the future.
I call this thing a "power interrupt safety switch", and am thinking
of marketing it... "Commercial power problems? PISS on it" :-) A UPS
would be ideal, but somehow, there's always a higher priority for my
limited funds.
An excellent idea (the relay wired that way)! And your marketing slogan is
GREAT!
One question: did you wire both legs of the AC power through the relay to be
like a DPDT switch? Reason I ask is as a safety consideration given the
possibly of a reversed hot and neutral; I've seen "professional" electricians
wire house and office circuits incorrectly at times. If you want to check
the wiring, an approx. $5 gadget from most any hardware store and mfd. by
SNAPIT and called a CIRCUIT TESTER, Cat.no. 49662 and about the size of a
3-prong-to-2-prong adapter has 3 colored lamps which will display the present
"state" of an AC outlet.
Thad Floryan [ thad@cup.portal.com ]dt@yenta.alb.nm.us (David B. Thomas) (01/15/91)
dwn@swbatl.sbc.com (David Neill-OKCy Mktg 405-278-4007) writes: >I call this thing a "power interrupt safety switch", and am thinking >of marketing it... "Commercial power problems? PISS on it" :-) I have also seen this invention called an "Irrevocably Interruptible Power Supply". My version would also have a timer in it, so it would come on after the power has been on for 30 seconds. That way, you get protection against wild power fluctuations, but unattended operation is still possible. little david -- Computer interfaces and user interfaces are as different as night and 1.
rwa@cs.athabascau.ca (Ross Alexander) (01/15/91)
templon@copper.ucs.indiana.edu (jeffrey templon) writes: >In article <37881@cup.portal.com> thad@cup.portal.com (Thad P Floryan) writes: >>White Sands Missile Range circa late '50s or early '60s: a soldier took a >>shortcut through the "beam" in a multi-megawatt RADAR installation and keeled >>over, and it wasn't apparent what happened until after the autopsy: certain >>internal organs were cooked. This incident is "rumored" to have been the Sticking your hands in the beam was SOP when the DEW line was being built. Those radars weren't quite so high powered, nor the beams so intense; and at -50 to -60 C, a hand warmer is an intensely interesting proposition. -- -- Ross Alexander rwa@cs.athabascau.ca (403) 675 6311 ve6pdq
murphyn@motcid.UUCP (Neal P. Murphy) (01/15/91)
thad@cup.portal.com (Thad P Floryan) writes: ... >A big concern should there ever be a nuclear war is that the EMP would take >out the entire telephone system, all computers, all radios, all radar, traffic >lights, etc etc etc so my answer would be "Yes, our military's electronic >items are susceptible as well." >And do NOT bring up "Tempest" shielding; that's only to prevent RFI emissions >FROM military equipment being detected, intercepted and decoded. One of the True, "Tempest" refers only to such shielding. However, a system CAN be shielded from EMP. It requires diligently applying a shield around *EVERYTHING*: the equipment to be protected, the power lines from the UPS, the data lines between terminals and computers, the UPS itself and connecting this shield to earth ground. Thus shielded, the system should be safe from EMP. NPN
murphyn@motcid.UUCP (Neal P. Murphy) (01/15/91)
thad@cup.portal.com (Thad P Floryan) writes: ... >White Sands Missile Range circa late '50s or early '60s: a soldier took a ... >internal organs were cooked. This incident is "rumored" to have been the >start of what we today know as MicroWave ovens. Though I was there at the My father worked on Navy radar installations after WWII. Even back then, it was common practive for the engineers to heat up their bag lunches by putting them in front of the radar beam. Microwaves in ovens excite sugar, oils/fats, and water. That's why one has to be careful when nuking a jelly doughnut: the dough may be tepid while the jelly is hot enough to cause 3rd degree burns. NPN
gmark@cbnewse.att.com (gilbert.m.stewart) (01/15/91)
In article <38023@cup.portal.com>, thad@cup.portal.com (Thad P Floryan) writes: > dwn@swbatl.sbc.com (David Neill-OKCy Mktg 405-278-4007) > in <1991Jan12.155433.11110@swbatl.sbc.com> writes: > Anyway, before bringing it back up (with new power supply), I > got a commercial power relay (16 amps!), and wired the power to > the relay coil through the contacts of the relay. This way, > when the power drops once, the relay contacts open, and no more ..... > I call this thing a "power interrupt safety switch", and am thinking > of marketing it... "Commercial power problems? PISS on it" :-) A UPS > would be ideal, but somehow, there's always a higher priority for my > limited funds. > > An excellent idea (the relay wired that way)! And your marketing slogan is > GREAT! Sorry to rain on your parade, but I posted this a couple years ago (?) and was told by a very helpful individual (I have the name saved somewhere, so don't let my lack of memory diminish the great help) that Radio Shack had a power strip/spike protector/power controller with exactly what I proposed. I bought one. It works GREAT! Maybe you could sell something cheaper, 'cause the combination was $59.95 or thereabouts. You could be depressed, but then again, let me tell you about the dozen or so other things I've thought of that I was beat to the punch on. HOWEVER, your slogan, I agree, is GREAT. Now, if RatShack needs a copywriter...! GMS
neal@mnopltd.UUCP (01/18/91)
->In article <1991Jan7.124138.19055@ims.alaska.edu> floyd@ims.alaska.edu (Floyd Davidson) writes:
->>
->[ ... lots of good stuff deleted ... ]
->>If you do want to do something along these lines, wrap a couple
->>turns through a high Q toriodal core. ...
->
->issue ... uh, suffice it to say a lightning strike took out a high
->voltage line and put it squarely in contact with the 220V feed to
->his neighborhood. He details the types of protection he had and what
->types of stuff survived and what didn't. In general MOV/coil circuits
->handle lightning strikes if they are several miles away or on the other
->side of a step-down transformer. More serious stuff - like what
->happened to Mr. Pournelle - can only be dealt with properly via an
->UPS, preferably with an isolation transformer and a good over-voltage
There is quite a variety in UPS's's. Many do leave your equipment directly
connected to the power line. Some provide isolation. I am aware of Best
UPS's's, which put a big ferro-resonant transformer between you and the
power line at all times. They say this can reduce a 2kv jolt down to 3v.
They also weigh a ton...
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