Mosquito Sound

[Ron Reaugh]

w_tom == Suraj Singh

Check the headers

 

[Kent Wills]

I was just walking down the street, when someone handed me a piece of
paper. I thought it was something for a free meal at Popeye's
Chicken. Instead, I found that on 23 Sep 2004 16:12:57 -0700,
surajs21@yahoo.com (Suraj Singh) wrote:

Surprised to see that no body talked about the capacitance of the
earth in this discussion.

Well, the OP did only ask about computers.

Lightening do not bother to hit the airplane. Even if it does it do
not damage anything. Airplane capacitance is too small so a very
minute flow of charge can change its potential to match the cloud
potential. flow of minute change means little current ( micro amp)
which wont damage anything.

Actually, airplanes do get hit. Probably more than most people
realize, although I don't have any actual cites to offer.

Imagine a situation where the plane has just taken off the ground,
lightening strikes its body and discharge to the earth through bottom
including pointed antennas in the wings; you can imagine the damage to
the circuit from where the antenna is connected.

Kiss that antenna good bye. It's toast.

As per the lightening is concerned one can not ignore earth if you are
close to it. You can dare to ignore if you are a much bigger mass
than earth.

Eh? If you had a much bigger mass than the earth, you couldn't
possibly be ON the earth. You couldn't possibly fit.

You can raise the common mode potential of the system (say PC and
Modem), it helps but up to what extent? The charge on it will seek the
earth and if a short and quick high conducting path in not provided,
it may break down the air gap and discharge to the nearest path to
earth through the mouse wire.

Which is why I think everyone should invest in a wireless optical
mouse

Concept of GPR will provide much better protection if the whole house
is considered as a sub system. It will be economical too.
Power strips provide protection but for small surges only.

No they don't, actually. Power strips are nothing more than
additional outlets. Surge Protection strips can add a degree of
protection. These are two different things. Always keep that in
mind.

Kent
--
Nie'se schlect sim'wa

 

[Chaos Master]

Br Dan Izzo writes within:

Cosmic Radio Signals can be polarized at 91mhz (fm); 160mhz (vhf); 610

This looks like someone on drugs, seeing 'patterns' on noise.

Sounds like a good lie.
There's nothing better than a good lie.

[]s
--
Chaos MasterŽ, posting from Brazil.
"Two of the most famous products of Berkeley are LSD and Unix. I don't think
that this is a coincidence." -- Anonymous
"I'd rather be hated for who I am, than loved for who I am not" - Kurt Cobain

The Evanescen(t/ce) HP: http://marreka.no-ip.com

 

[Robert Baer]

Larry wrote:

Hello,

I was hoping someone could send me in the right direction to find
information on a low frequency detector.
Either a low cost purchased unit, or the schematics to build one.
I am trying to detect in the 0- 30Hz range.
I appreciate any info, Larry

Use an opamp with low 1/f noise, and a loop antenna.

 

[John Woodgate]

I read in sci.electronics.design that Robert Baer
<robertbaer@earthlink.net> wrote (in <41552C6E.661306FF@earthlink.net&gt
about 'ELF detector', on Sat, 25 Sep 2004:

Larry wrote:

Hello,

I was hoping someone could send me in the right direction to find
information on a low frequency detector.
Either a low cost purchased unit, or the schematics to build one.
I am trying to detect in the 0- 30Hz range.
I appreciate any info, Larry

Use an opamp with low 1/f noise, and a loop antenna.

And a Pixie tube, of course.
--
Regards, John Woodgate, OOO - Own Opinions Only.
The good news is that nothing is compulsory.
The bad news is that everything is prohibited.
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk

 

[Ken Smith]

In article <13667c89.0409242355.764c64f2@posting.google.com>,
Larry <gemlover@tampabay.rr.com> wrote:

Hello,

I was hoping someone could send me in the right direction to find
information on a low frequency detector.
Either a low cost purchased unit, or the schematics to build one.
I am trying to detect in the 0- 30Hz range.

The zero on the bottom end of the range can be trouble.

You can get GMRs from Digikey.

--
--
kensmith@rahul.net forging knowledge

 

[Ken Smith]

In article <41552C6E.661306FF@earthlink.net>,
Robert Baer <robertbaer@earthlink.net> wrote:

Larry wrote:

Hello,

I was hoping someone could send me in the right direction to find
information on a low frequency detector.
Either a low cost purchased unit, or the schematics to build one.
I am trying to detect in the 0- 30Hz range.
I appreciate any info, Larry

Use an opamp with low 1/f noise, and a loop antenna.

You didn't give enough details. How big does the loop have to be to do
the "0-" part of the range?


--
--
kensmith@rahul.net forging knowledge

 

[Ed Price]

"Chaos Master" <spam@spam.com.INVALID> wrote in message
news:MPG.1bbe99b5d61d920a989721@news.individual.net...

SNIP

Chaos MasterŽ, posting from Brazil.
"Two of the most famous products of Berkeley are LSD and Unix. I don't
think
that this is a coincidence." -- Anonymous
"I'd rather be hated for who I am, than loved for who I am not" - Kurt
Cobain

The Evanescen(t/ce) HP: http://marreka.no-ip.com

I admire Kurt for being a good shot!

Ed
wb6wsn

 

[Ed Price]

"Ken Smith" <kensmith@green.rahul.net> wrote in message
news:cj42mn$243$1@blue.rahul.net...

In article <13667c89.0409242355.764c64f2@posting.google.com>,
Larry <gemlover@tampabay.rr.com> wrote:
Hello,

I was hoping someone could send me in the right direction to find
information on a low frequency detector.
Either a low cost purchased unit, or the schematics to build one.
I am trying to detect in the 0- 30Hz range.


The zero on the bottom end of the range can be trouble.

I think that can be fixed with suitable software.

Ed
wb6wsn

 

[Ed Price]

"Tim Shoppa" <shoppa@trailing-edge.com> wrote in message
news:bec993c8.0409250915.3babcb6d@posting.google.com...

gemlover@tampabay.rr.com (Larry) wrote in message
news:<13667c89.0409242355.764c64f2@posting.google.com>...
Hello,

I was hoping someone could send me in the right direction to find
information on a low frequency detector.
Either a low cost purchased unit, or the schematics to build one.
I am trying to detect in the 0- 30Hz range.
I appreciate any info, Larry

A 100W light bulb does a good job for me. Its sensitivity extends
all the way to 60Hz, in fact.

Tim.

Older hams know that 100 Watt light bulbs have a frequency response to at
least 50 MHz! But they must roll off badly above 1 GHz, because they never
show the power I'm really putting out!

Ed
wb6wsn

 

[Ken Smith]

In article <lAk5d.68220$9Y5.61521@fed1read02>,
Ed Price <edprice@cox.net> wrote:

"Ken Smith" <kensmith@green.rahul.net> wrote in message
news:cj42mn$243$1@blue.rahul.net...
In article <13667c89.0409242355.764c64f2@posting.google.com>,
Larry <gemlover@tampabay.rr.com> wrote:
Hello,

I was hoping someone could send me in the right direction to find
information on a low frequency detector.
Either a low cost purchased unit, or the schematics to build one.
I am trying to detect in the 0- 30Hz range.


The zero on the bottom end of the range can be trouble.


I think that can be fixed with suitable software.

I doubt software can do it. You need to divide by zero. Most programmers
have a hard time writing code that does that successfully.

--
--
kensmith@rahul.net forging knowledge

 

[Steve]

Lewin,
I worked for Nicolet as a final test tech about 20 years ago, and of
course we just shipped the probes we were given not realizing they were anything out
of the ordinary. Unfortunately, my service manual for the 3091 either doesn't
seem to want to be found. They are available via the web. The only genuine
Nic' scope probe I have has no adjustment apparent to me on the probe itself.
(?? and !) That would seem to suggest an internal adjustment -- I recall a
cylindrical pf range trimmer that needed adjustment, with a brass screw.
One hint, from the 1x scope probe I have here, is that it does have a 33 Ohm
resistor in series with the probe cable, located at the BNC. So perhaps
they are more special than I ever realized or at least remember. The 4094
that I own works fine with plain old scope probes of "today."

Given your present slow application, you should be fine for
your immediate need with nearly any probe.

Don't know if this really helps much. I'll try to rattle a few
cob webs in my mind and ask a few old contacts to see what I can find yet.
My 4094 needs several new Grigsby switches, but so do they all; I doubt
I can find what I need myself.

Thanks, Steve


Lewin A.R.W. Edwards wrote:

I recently acquired a Nicolet 3091 digital storage scope, vintage
circa 1982. The manual is amusing; for instance, it says that the
device has 16x12 of RAM, and a single screenful is 4096 12-bit words -
it is possible to dump out an entire screenful on the RS232 interface,
but "due to memory limitations of personal computers, you will
probably not want to acquire the entire image".

It's an audio-bandwidth scope (speced 300kHz BW, up to 1MS/s). I have
a much better digital scope, but this freebie has RS232 built in, and
it also has a couple of useful features like a "virtual pen-recorder"
mode. I want to use it for unattended analysis of battery chargers.

Anyway, I'm having trouble finding a probe that will match this scope
properly. Here's what the calibrator output looks like:
http://www.larwe.com/dsc00461.jpg>. That's the best I can adjust it
to using the trimcap on the probes available to me (mostly x1/x10
switchable units of post-1998 vintage at oldest). If I just hook a
piece of wire to the cal output, the trace looks nice and square. So
it's a probe capacitance issue.

What characteristics should I look for in a probe for such an ancient
scope?

 

[Tom Woodrow]

Steve,

Did you ever work with a John Holton while you were at Nicolet?

Tom Woodrow

Steve wrote:

Lewin,
I worked for Nicolet as a final test tech about 20 years ago, and of
course we just shipped the probes we were given not realizing they were anything out
of the ordinary. Unfortunately, my service manual for the 3091 either doesn't
seem to want to be found. They are available via the web. The only genuine
Nic' scope probe I have has no adjustment apparent to me on the probe itself.
(?? and !) That would seem to suggest an internal adjustment -- I recall a
cylindrical pf range trimmer that needed adjustment, with a brass screw.
One hint, from the 1x scope probe I have here, is that it does have a 33 Ohm
resistor in series with the probe cable, located at the BNC. So perhaps
they are more special than I ever realized or at least remember. The 4094
that I own works fine with plain old scope probes of "today."

Given your present slow application, you should be fine for
your immediate need with nearly any probe.

Don't know if this really helps much. I'll try to rattle a few
cob webs in my mind and ask a few old contacts to see what I can find yet.
My 4094 needs several new Grigsby switches, but so do they all; I doubt
I can find what I need myself.

Thanks, Steve


Lewin A.R.W. Edwards wrote:


I recently acquired a Nicolet 3091 digital storage scope, vintage
circa 1982. The manual is amusing; for instance, it says that the
device has 16x12 of RAM, and a single screenful is 4096 12-bit words -
it is possible to dump out an entire screenful on the RS232 interface,
but "due to memory limitations of personal computers, you will
probably not want to acquire the entire image".

It's an audio-bandwidth scope (speced 300kHz BW, up to 1MS/s). I have
a much better digital scope, but this freebie has RS232 built in, and
it also has a couple of useful features like a "virtual pen-recorder"
mode. I want to use it for unattended analysis of battery chargers.

Anyway, I'm having trouble finding a probe that will match this scope
properly. Here's what the calibrator output looks like:
http://www.larwe.com/dsc00461.jpg>. That's the best I can adjust it
to using the trimcap on the probes available to me (mostly x1/x10
switchable units of post-1998 vintage at oldest). If I just hook a
piece of wire to the cal output, the trace looks nice and square. So
it's a probe capacitance issue.

What characteristics should I look for in a probe for such an ancient
scope?

 

[Steve]

Lewin A.R.W. Edwards wrote:

Hi Steve,

I worked for Nicolet as a final test tech about 20 years ago, and of
course we just shipped the probes we were given not realizing they were
anything out

Heh, heh. Well, maybe you handled this one. It was last cal'd in
December 1983 and it was signed off by one Douglas M. Abner.

I don't remember him. Actually I showed up in '85 to '86.

In actual
point of fact, it was probably never cal'd after manufacture, because it
was used for engineering tests - at my company, equipment that isn't
used for actual final Q/A or other important things (e.g. UL or FCC cert
work) is tagged "CALIBRATION NOT REQUIRED".

We've got vast graveyards of equipment that are slowly being tagged for
disposal. A true friend, gentleman and potential saint in the
"graveyard" building occasionally drops by my cube (I work in a
different building) and says "There's a [xyz] about to go in the
trash..." I'm hoping for another one of these 3091s, rumored to be in
the same general area of the junkpile, to use as spare parts if
necessary. I was shocked to see that a unit on eBay was going with a
starting bid of $200-and-something. It didn't sell, of course.

My working 4094 I bought for $5.00. A non-working one I got for $15.00!
They sold originally sold for 1000 to near 10,000 times that new if you
bought a lot of bells and whistles!

of the ordinary. Unfortunately, my service manual for the 3091 either
doesn't
seem to want to be found. They are available via the web. The only genuine

I've got the original letter-size printed service manual, as well as the
half-letter-size user manual. There isn't any information in the service
manual on what's inside the probes or how to calibrate them.

One hint, from the 1x scope probe I have here, is that it does have a 33 Ohm
resistor in series with the probe cable, located at the BNC. So perhaps

I did just find a box O' junk, with a 3091 ADC board in it, and there is
no such piston cap on it. There are two pairs of 3 to 10 pf trimmers. Please
just forget what I said about the internal adjustment... I even
wonder if this Nicolet scope probe was for a 3091. The years cloud the memory.

Hmmm.

Given your present slow application, you should be fine for
your immediate need with nearly any probe.

Well yes, that's true, but I would like to get the instrument working as
nominally as possible. I'm contemplating hacking up a probe myself, by
modifying an existing probe. Since it appears to get a good waveform if
I use a dumb wire, maybe I should take a "new" probe, pull out any
smarts inside it, and add that 33R resistor. Thanks for the pointer!

My 4094 needs several new Grigsby switches, but so do they all; I doubt

Grigsby switches - what are those? I found the only thing wrong with
this old beastie was (a) tube rather out of focus (I can compensate
slightly with the focus adjustment, but not much - I'm guessing a cap
job is called for at this point in time), and (b) all the rotary
switches desperately needed cleaning.

The rotary switches are made by Grigsby. They are the major source of
demise for many a Nicolet scope. Cleaning only delays the inevitable.
As I only got the two 4094's in the past year, I don't really have
much experience about the "end of life" of these scopes! Very unsure
about how much luck one would have ripping one apart to clean
it, or if possible at all. At the factory we would have never done
anything but put a new one in for the occasional infant failure during
final test.


Good luck, and I'll try to see if I can come up with anymore help.
May take weeks.

Thanks, Steve

 

[Steve]

Tom Woodrow wrote:

Steve,

Did you ever work with a John Holton while you were at Nicolet?

Tom Woodrow

Sorry, he looks to be before my time there, from what I could Google about
him, if this is him:

http://www.engr.wisc.edu/ie/newsletter/2000_spring/holton.html

Looks like he may have been in the Bio-medical division.
Of course I was in the O-scope division. There were hundreds working there,
in 1/2 dozen buildings. Not anything close to what's left, from what I've
heard.

 

[John Woodgate]

I read in sci.electronics.design that Ken Smith
<kensmith@green.rahul.net> wrote (in <cj4o62$g7l$8@blue.rahul.net&gt
about 'ELF detector', on Sat, 25 Sep 2004:

I doubt software can do it. You need to divide by zero. Most
programmers have a hard time writing code that does that successfully.

IF DIVISOR = 0, THEN RESULT = 1E+38 ELSE RESULT = DIVIDEND/DIVISOR

It's the order in which you write it that matters. (;-)
--
Regards, John Woodgate, OOO - Own Opinions Only.
The good news is that nothing is compulsory.
The bad news is that everything is prohibited.
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk

 

[Robert Baer]

John Woodgate wrote:

I read in sci.electronics.design that Ken Smith
kensmith@green.rahul.net> wrote (in <cj4o62$g7l$8@blue.rahul.net&gt
about 'ELF detector', on Sat, 25 Sep 2004:

I doubt software can do it. You need to divide by zero. Most
programmers have a hard time writing code that does that successfully.

IF DIVISOR = 0, THEN RESULT = 1E+38 ELSE RESULT = DIVIDEND/DIVISOR

It's the order in which you write it that matters. (;-)
--
Regards, John Woodgate, OOO - Own Opinions Only.
The good news is that nothing is compulsory.
The bad news is that everything is prohibited.
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk

ORDER??????????
What is *that*??

 

[Tom Woodrow]

Don't think that this was the same guy although the time frame is about
right. The John Holton I knew was a vietnam vet and still had long hair
and beard so I can't tell from the picture.


On another note, when I was at Aydin we had a 4094. Was a great DSO and
was the world's best glitch catcher. We did high voltage stuff and just
the ground faults would kill a Tec scope. We never did fry a 4094. I
coud still use one once in a while, but the last one we bought (another
company) disappeared after a move to a new building.

Tom Woodrow

Steve wrote:

Tom Woodrow wrote:


Steve,

Did you ever work with a John Holton while you were at Nicolet?

Tom Woodrow


Sorry, he looks to be before my time there, from what I could Google about
him, if this is him:

http://www.engr.wisc.edu/ie/newsletter/2000_spring/holton.html

Looks like he may have been in the Bio-medical division.
Of course I was in the O-scope division. There were hundreds working there,
in 1/2 dozen buildings. Not anything close to what's left, from what I've
heard.

 

[Ed Price]

"John Woodgate" <jmw@jmwa.demon.contraspam.yuk> wrote in message
news:bkJTvRCl5mVBFwXa@jmwa.demon.co.uk...

I read in sci.electronics.design that Ken Smith
kensmith@green.rahul.net> wrote (in <cj4o62$g7l$8@blue.rahul.net&gt
about 'ELF detector', on Sat, 25 Sep 2004:

I doubt software can do it. You need to divide by zero. Most
programmers have a hard time writing code that does that successfully.

IF DIVISOR = 0, THEN RESULT = 1E+38 ELSE RESULT = DIVIDEND/DIVISOR

It's the order in which you write it that matters. (;-)
--
Regards, John Woodgate, OOO - Own Opinions Only.
The good news is that nothing is compulsory.
The bad news is that everything is prohibited.
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk

Precisely, solved in Basic, circa 1968!
Or in Fortran, even earlier!
That's how coders solve those pesky little "special cases". <g>

Ed
wb6wsn

 

[John Woodgate]

I read in sci.electronics.design that Robert Baer
<robertbaer@earthlink.net> wrote (in <4156705F.31F860EE@earthlink.net&gt
about 'ELF detector', on Sun, 26 Sep 2004:

John Woodgate wrote:

I read in sci.electronics.design that Ken Smith
kensmith@green.rahul.net> wrote (in <cj4o62$g7l$8@blue.rahul.net&gt
about 'ELF detector', on Sat, 25 Sep 2004:

I doubt software can do it. You need to divide by zero. Most
programmers have a hard time writing code that does that successfully.

IF DIVISOR = 0, THEN RESULT = 1E+38 ELSE RESULT = DIVIDEND/DIVISOR

It's the order in which you write it that matters. (;-)
--
Regards, John Woodgate, OOO - Own Opinions Only.
The good news is that nothing is compulsory.
The bad news is that everything is prohibited.
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk

ORDER??????????
What is *that*??

Ask your friendly local Marine sergeant.
--
Regards, John Woodgate, OOO - Own Opinions Only.
The good news is that nothing is compulsory.
The bad news is that everything is prohibited.
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk