In article ,
(Bill Bowden) writes:

Watson A.Name - 'Watt Sun' wrote in message
...
In article , richard.p.henry@saic
mentioned...

"Tom Sevart" wrote in message
...

"WB3FUP (Mike Hall)" wrote in message
...
10KV to fire magnetron in counter battery radar. Took six marines to
stop
me from burying my screw driver in the chest of the asshole that
thought
it
would be cute to push the radiate button.

I remember hearing the story of an Air Force tech working on a 30' radar
dish. For some dumb reason, someone energized it and promptly
microwaved
him to death.

Some of these stories are hair rasing... and I'm too much of a weenie to
stick my tongue on a 9V battery...

A Raytheon corporate legend is that one of the engineers discovered the
microwave oven principle when a radar melted a chocolate bar in his shirt
pocket.

When I was in the army at Ft. Monmouth, NJ, we trained on a radar
trainer, had a klystron that put out 1W to the horn on the top of the
unit. We could put our finger over the horn and feel it get mildly
warm from the RF.

Big deal. The Real Thing put our 5 megawatts!

Sure, but the pulse width is only a microsecond, so the
average power is only 5 watts at one pulse per second.
I forget the rep rate of the one I woked on but at
6uS per mile and 400 miles round trip, the rep rate
would be about 400 Hz. So it's 400 times 5, or 2KW.

-Bill

A very rough estimate of "radar range" (time out to return of echo)
is 500 feet per microsecond. For a 200 mile search radar the time
out to echo return is 2+ milliseconds, depending on whether it is
calibrated for statute or nautical miles. Typical PRF for those 200
mile search radars was 400 Hz (PRT of about 2.5 mSec).

Average power output is Peak x ((pulse width)/(repetition time)) or
5 MW divided by 2500 = 2 KW.

2 KW concentrated in a 2 to 5 degree cone can have a devastating
heating effect on human tissue.

One may or may not be "in" the cone of the beam right up close
to the feedhorn but, with the construction of most search radars
(maritime or ground) there isn't much walk-around space to get
away from the feedhorn or the very close in-person effects of
microwave radiation.

When working on HIGH POWER RF at any frequency, believe in
the inverse square law and put as much distance from the antenna
as possible...or have a trusted person down on the power controls
who keeps the thing OFF while up there doing whatever.

I think it would be an interesting subject to compare peak power
RF effects versus average power RF effects. I can't seem to find
much on that in hundreds of pages of medical-biological reports
on the effects of RF radiation on human tissue. Unfortunately,
that has been pretty well shunted aside so that someone can get
their pet "alternate universe" speculations going on in here. :-)

All this gee-whizzy speculation stuff leaves me shocked.
But not fatally so...

Len Anderson
retired (from regular hours) electronic engineer person

Good point for safety, year or so ago, a new ham lost his life
while putting up an antenna on the roof of a friends home,
also a new ham. The antenna contacted house power lines.

73 joe

Avery wrote:

clipped....
I mention this because amateur radio nearly always involves outside
antennas in urban areas close to utility power wiring on poles. The
possibility of fatal or terrible electric shock isn't confined to some
radio-electronic box interior...it exists out in the open, in plain sight.
Keep it in mind to avoid frying that mind.

Len Anderson
retired (and still living) electronic engineer person

Good point for safety, year or so ago, a new ham lost his life
while putting up an antenna on the roof of a friends home,
also a new ham. The antenna contacted house power lines.

73 joe

Avery wrote:

clipped....
I mention this because amateur radio nearly always involves outside
antennas in urban areas close to utility power wiring on poles. The
possibility of fatal or terrible electric shock isn't confined to some
radio-electronic box interior...it exists out in the open, in plain sight.
Keep it in mind to avoid frying that mind.

Len Anderson
retired (and still living) electronic engineer person

hi,

A gfci monitors for a current imbalance between the Hot and Neutral
conductors.
A ground connection is not necessary. Per NEC 210-7

http://www.leviton.com/sections/techsupp/faq.htm#2 wire gfi


Regards.




"Gary S." wrote:

On Fri, 08 Aug 2003 17:01:16 -0400, Alex wrote:

GFCI?

Ground Fault Circuit Interruptor.

It detects a sudden rise in current to ground and shuts the circuit
off in a fraction of a second.

Fuses protect the circuit, GFCI protects people.

The present US Electrical Code requires them in areas where water is
nearby, including bathrooms, kitchens, garages, and outdoors.

You are encouraged to use them in other places where there is danger
of zapping yourself.

They are not a guarantee, but they boost the odds in your favor.

hi,

A gfci monitors for a current imbalance between the Hot and Neutral
conductors.
A ground connection is not necessary. Per NEC 210-7

http://www.leviton.com/sections/techsupp/faq.htm#2 wire gfi


Regards.




"Gary S." wrote:

On Fri, 08 Aug 2003 17:01:16 -0400, Alex wrote:

GFCI?

Ground Fault Circuit Interruptor.

It detects a sudden rise in current to ground and shuts the circuit
off in a fraction of a second.

Fuses protect the circuit, GFCI protects people.

The present US Electrical Code requires them in areas where water is
nearby, including bathrooms, kitchens, garages, and outdoors.

You are encouraged to use them in other places where there is danger
of zapping yourself.

They are not a guarantee, but they boost the odds in your favor.

In article , Paul Burridge
writes:

On 09 Aug 2003 19:46:02 GMT, (Avery Fineman)
wrote:

If the source has over 30 Volts and can supply over 30 milliamperes
through the cardiac region, you will go into cardiac fibrilation.

Sorry, Len, but I can't see it. I routinely check for HV on the anodes
of certain smallish valves with bare fingers and can't even begin to
feel anything under about 80 volts (at very much more current
capability than 30mA) at the low end. However, I read somewhere that
some guy died from just a 12V 'shock' - must have been a world
record.. :-(

I'm not concerned with what YOU do personally, nor will I set any
"standards" for all humans based on what one human can or can't
do or feel.

I got the "30-30" phrase while working at Birtcher Instruments, a
semiconductor test instrument maker and a division of Birtcher
Medical that made several different medical electronic instruments
(EKG, RF knife/cautery, defibrilators,etc.). Someone at Birtcher
Medical told me about it. I was Chief Engineer at Birtcher Instruments
in Monterey Park, California, a suburb of Los Angeles (not the upstate
Monterey, CA, where some FedEx deliveries went, hi). I don't think
that my employer at the time would give me false information.

The City of Los Angeles building and safety codes don't require
inspection of 24 VAC wiring in residences and that sort of wiring is
common here for furnace and HVAC controls, doorbells, etc. That
AC voltage is never considered "high voltage." That is probably true
of the USA National Electrical Code although I haven't read one
recently (I've only read the coding in the Numeric Electromagnetic
Code recently, quite different from the other "NEC").

I really don't know the medical-biological low threashold for direct
cardiac stimulation through an opening in the chest cavity. I don't
care to know. I care to know NOT to futz around with my or anyone
else's body with anything above the "30-30" limits.

If YOU want to experiment with your own body, feel free. Then you
transport yourself to that other "reality." When you get there, ask
someone there to shock themselves into this reality and tell us all what
it is like "over there." I live in THIS reality where survival depends on
not treating electricity cavalierly like it was words in a newsgroup.

Happy zapping.

Len Anderson
retired (from regular hours) electronic engineer person

In article , Paul Burridge
writes:

On 09 Aug 2003 19:46:02 GMT, (Avery Fineman)
wrote:

If the source has over 30 Volts and can supply over 30 milliamperes
through the cardiac region, you will go into cardiac fibrilation.

Sorry, Len, but I can't see it. I routinely check for HV on the anodes
of certain smallish valves with bare fingers and can't even begin to
feel anything under about 80 volts (at very much more current
capability than 30mA) at the low end. However, I read somewhere that
some guy died from just a 12V 'shock' - must have been a world
record.. :-(

I'm not concerned with what YOU do personally, nor will I set any
"standards" for all humans based on what one human can or can't
do or feel.

I got the "30-30" phrase while working at Birtcher Instruments, a
semiconductor test instrument maker and a division of Birtcher
Medical that made several different medical electronic instruments
(EKG, RF knife/cautery, defibrilators,etc.). Someone at Birtcher
Medical told me about it. I was Chief Engineer at Birtcher Instruments
in Monterey Park, California, a suburb of Los Angeles (not the upstate
Monterey, CA, where some FedEx deliveries went, hi). I don't think
that my employer at the time would give me false information.

The City of Los Angeles building and safety codes don't require
inspection of 24 VAC wiring in residences and that sort of wiring is
common here for furnace and HVAC controls, doorbells, etc. That
AC voltage is never considered "high voltage." That is probably true
of the USA National Electrical Code although I haven't read one
recently (I've only read the coding in the Numeric Electromagnetic
Code recently, quite different from the other "NEC").

I really don't know the medical-biological low threashold for direct
cardiac stimulation through an opening in the chest cavity. I don't
care to know. I care to know NOT to futz around with my or anyone
else's body with anything above the "30-30" limits.

If YOU want to experiment with your own body, feel free. Then you
transport yourself to that other "reality." When you get there, ask
someone there to shock themselves into this reality and tell us all what
it is like "over there." I live in THIS reality where survival depends on
not treating electricity cavalierly like it was words in a newsgroup.

Happy zapping.

Len Anderson
retired (from regular hours) electronic engineer person

I had a NDE when I congratulated a young lady on her pregnancy, and it
turned out she wasn't pregnant. Near-fatal shock, it was, too.

Roy Lewallen, W7EL

I had a NDE when I congratulated a young lady on her pregnancy, and it
turned out she wasn't pregnant. Near-fatal shock, it was, too.

Roy Lewallen, W7EL

Paul Burridge wrote:

On Fri, 08 Aug 2003 21:36:08 GMT, Gary S. Idontwantspam@net wrote:

On Fri, 08 Aug 2003 17:01:16 -0400, Alex wrote:

GFCI?

Ground Fault Circuit Interruptor.

How splendid! We call them Residual Current Circuit Breakers in
England. Typically they trip out at just over the amount of current
required to kill someone. Keeps the bills down that way. In *this*
universe, anyway.

They're Earth Leakage Detectors in Australia. ;-)

Rob