HDTenEightyP/NetNews huggingface dataset:
Organization: Penn State University
Date: Tue, 26 Jan 1993 11:05:32 EST
From: <FWR100@psuvm.psu.edu>
Newsgroups: sci.electronics
Subject: Re: Auto "tow" sensor idea needed

I don't know how well the "turning wheel" method will work.  A lot of towing
companies use the little wheels that lift yours off the ground (dollies?).
None of your wheels turn.  If you have a front wheel drive car with the parking
brake on, or 4WD, this is the only way they can tow it.

Enough picking on other people's suggestions :-)  Here's my idea -
Have a multi-position tilt sensor.  Basically, a pendelum that will touch one
of several contacts depending on tilt.  Once the system is armed, the alarm
will sound if the pendelum changes position.  Should be easy to build from
some TTL gates - basically just a comparator and a shift register.

-Frank
Newsgroups: sci.electronics
From: laird@pasture.ecn.purdue.edu (Kyler Laird)
Subject: AC light dimmer from counter?
Organization: Purdue University Engineering Computer Network
Date: 25 Jan 93 20:53:40 GMT

I'm trying to build _cheap_ X10-like modules for controlling loads in
a new house.  I'll be dropping dedicated cable, so I'm planning to use
RS-485 interfaces to a MC14469 (addressable async rec/trans).  I'd like
to use the 7-bit parallel output of the 14469 to drive two dimmers in
some modules.

I was thinking that the easiest way to do this is to run three lines
to each (of two) counter's inputs so that when reset they load this
value.  A clock of 60*2*2^3 Hz would drive the counter, and reset
would be provided by a zero-cross detector built in to the remote power
supply.  (Cut power at zero cross, but have modules run off of local
capacitors.)  The overflow output would then drive a triac.

In operation, VCC for the module would go low (indicating that a zero
cross has been detected) resetting the counter (but not the entire
module since it's running off of a capacitor), at reset the three bits
present from the network interface would be loaded and the overflow
cleared.  This would turn off the triac.  When the count overflows, the
triac would be turned on until it detects zero cross.  At zero cross,
the cycle repeats.

So...will that do it?  Can I easily get a zero cross detector built in
to the triac (instead of having it done remotely)?  Can I reduce or
eliminate the buzzing I associate with these dimmers?

Thanks for the help!

--kyler






Xref: sparky sci.electronics:23280 alt.radio.pirate:799
From: aj008@cleveland.Freenet.Edu (Aaron M. Barnes)
Newsgroups: sci.electronics,alt.radio.pirate
Subject: Re: FM power calculations needed
Date: 24 Jan 1993 05:08:48 GMT
Organization: Case Western Reserve University, Cleveland, Ohio (USA)
NNTP-Posting-Host: slc10.ins.cwru.edu


This might be news to some of you folks,but a gentleman in Phoeni
x,Arizona won his case in court over broadcasting on FM.
The court said the FCC has no jurisdiction over him since his sig
nal does not cross international,state, or marine borders.
He is called in legal terms an INTRASTATE,or inside of one state,
roadcaster.He is free to do as he wishes as long as it is noncomm
ercial.
For any of you in the north Phoenix area,he is on 88.9 with 1.5 w
atts.He is located on 5th street near Union Hills.Broadcasts are
in the evenings between 6 and 11 PM.
I would do it myself,but I live in Cleveland,Ohio,so I have both an international border and a large marine border(Lake Erie).
You must also be careful if you are operating near any major rive
rs.Therte have been people busted because of being monitored by b
oats on the Ohio river.

But,by all means,those of you in Arizona,It is perfectly leagal no
w to be on FM.Of course it always was,but we now have court decisi
on on the matter.

Those of you in Phoenix,if you have been watching the TV news in 
the past year,alredy know about this.I know for a fact there was
a big story on channel 10.Dont know for sure about any of the oth
er ones though.

-- 
Aaron
aj008@cleveland.freenet.edu
Place for Ted Kennedy in Clinton administration? Head of Departme
nt of Transportation roads and BRIDGES division,of course!
Xref: sparky sci.electronics:23330 rec.radio.swap:3681
From: glusk@mechcad3.esd.sgi.com (Mark Glusker)
Newsgroups: sci.electronics,rec.radio.swap
Subject: HP 651B Test Osc. For Sale
Date: 25 Jan 93 14:38:31 GMT
Reply-To: glusk@mechcad3.esd.sgi.com (Mark Glusker)
Organization: Silicon Graphics, Inc.


FOR SALE: Hewlett-Packard 651B Test Oscillator

- generates sine waves from 10 Hz to 10 MHz.
- maximum output: 3.16V into 50 or 600 ohms
- 50 ohm and 600 ohm BNC outputs
- RMS analog output meter, from 0.1 mV to 3.16V full scale
- 90 dB attenuator in 10 dB steps

Asking $200 + shipping.  Includes manual (photocopy) + cord.



Mark Glusker, glusk@esd.sgi.com
Newsgroups: sci.electronics
From: rusty@anasazi.com (Rusty Carruth)
Subject: Re: video thru an audio snake????
Organization: Anasazi, Inc.  Phoenix, Arizona USA
Date: Mon, 25 Jan 1993 21:05:11 GMT

In article <1993Jan15.185545.5015@wkuvx1.bitnet> scottcr@wkuvx1.bitnet writes:
>In article <1993Jan15.183535.16799@samba.oit.unc.edu>, Curt.Miller@launchpad.unc.edu (Curt Miller) writes:
>
>> 	I have a question.  I was wondering if it would be possible 
>> to send a baseband video signal through an audio snake?  I'm not too
....
>
>It's usually easier to run RG-59 for utility use like this.
>
>Good luck.

Boy, I'd sure agree with this.  Is there any possibility of  adding
the RG-59 to the snake?  Even if its just by tie-wrapping (or otherwise
"permanently connecting") the RG to the snake???

-- 
73 de Rusty Carruth, N7IKQ   P.O. Box 27001, Tempe, AZ 85285
      (602) 870-3330         !'s:{ames!ncar!noao!asuvax,mcdphx}!anasaz!rusty
@'s: rusty@anasazi.com       LastResort: rusty%anasaz.UUCP@asuvax.eas.asu.edu
Join the Usenet Un-Net:      1700-1900Z  Saturdays, 28.410 or 28.390 MHz
From: canright@convex.com (Robert Canright)
Newsgroups: sci.electronics
Subject: Re: Digital Filtering
Keywords: Digital Filter software, Matlab
Date: 26 Jan 93 15:25:10 GMT
Article-I.D.: convex.canright.728061910
Organization: Engineering, CONVEX Computer Corp., Richardson, Tx., USA
X-Disclaimer: This message was written by a user at CONVEX Computer
              Corp. The opinions expressed are those of the user and
              not necessarily those of CONVEX.

In <aPLyXB1w165w@cpuig> cpuig@infoserv.com (Carlos M. Puig) writes:

>cmh@eng.cam.ac.uk (C.M. Hicks) writes:

>> fitzpa@eeel.nist.gov (Gerry FitzPatrick) writes:
>> 
>> >I need to design a digital filter (either a notch filter or
...
>> >Any ideas on how to write a subroutine that would perform this
>> >digital filtering on stored data?  Any good books on designing
>> >digital filters?
>> 
>> 'MatLab' from Mathsworks would be absolutely ideal, although rather expensive
...

If I remember correctly, I once saw a student version of a software package for
digital filter design in the campus bookstore of the University of Central
Florida, Orlando.  The trademark was a butterfly & the company name might
have been Monarch.
From: amigaman@zombie.oulu.fi (Jyrki Hoisko)
Newsgroups: sci.electronics
Subject: Re: Car Phones?
Date: 26 Jan 93 17:15:05 GMT
Organization: University of Oulu, Finland
X-Newsreader: TIN [version 1.1 PL6]

Jason Austin (jason@ab20.larc.nasa.gov) wrote:

: 	My dad got himself a Motorola phone and has been very pleased
: with it; I couldn't even tell he was on a mobile.  The audio quality

My dad got himself a Nokia phone (finnish!) and has been very pleased
with it... :) :) :)  as well as I too!!

: --
: Jason C. Austin
: j.c.austin@larc.nasa.gov
: 
  -*- Jyrki -*-
  amigaman@phoenix.oulu.fi
From: bill@pauli.lv-physics.nevada.edu (Bill ODonnell)
Newsgroups: sci.electronics
Subject: Laser Radar Detector Questions
Date: 24 Jan 93 17:49:54 GMT
Organization: UNLV Department of Physics


	I am a grad student taking a laser applications course
and was assigned a project to design a laser radar detector.

What I need to know is:

	1) Do they use Doppler, time of flight, or both?
	2) If time of flight, what is the rep rate of the pulses?
	3) If Doppler, what frequency is the carrier modulated at?
	4) What is the wavelength of the laser used?

An old Popular Science (Sep. 90) reported that the time of flight
method was used with a pulse every 3ms.  My own opinion is that
Doppler isn't used because very high modulation frequencies would
be needed for good accuracy.???  If anyone knows of a standard or
the specs of a specific brand a short message would be very
helpful.


						Thanks in advance,
						Bill O'Donnell
Newsgroups: sci.electronics
From: sean@dip1.ee.uct.ac.za (Sean Borman)
Subject: Deperately seeking LCD ...
Date: Mon, 25 Jan 93 12:56:10 GMT
Organization: University of Cape Town
X-Newsreader: TIN [version 1.1 PL8]

Hi there..

I have a requirement (I want to make a stereo viewer) for large (5 to 10 square
centimeters) lcd block displays.  Not 7 segment, not alphanumeric, just plain
blank LCD displays !

Unfortunately I'm clueless as to where to get hold of such things considering
that I'm on a kinda quiet continent.

If anyone has any idea where to get such a beast, or who knows a good supplier
of LCD products, then please e-mail me.

Many thanks

Sean.
From: mdk@col.hp.com (Mark Keisling)
Newsgroups: sci.electronics
Subject: Re: Dumb/simple UART chips
Date: 28 Jan 1993 17:42:29 GMT
Organization: HP Colorado Springs Division
Distribution: world
NNTP-Posting-Host: hpctdjj.col.hp.com

bote@access.digex.com (John Boteler) writes:
> 
> Is there a dumb UART readily available?
>  
> I am designing a box that sends out serial telemetry based on 8 switches
> being ON or OFF. A serial interface looks like a good way to do it. I
> don't need interrupts, I don't need FIFOs, I don't need modem status
> bits, I don't need none of that stuff.
>  
> I would rather not bump the level of complexity up several notches by
> requiring a microcontroller (and its firmware) just to initialize the
> UART speed and so forth. Is there a really dumb UART that can come up in
> a known state and just shovel data? National Semiconductor's 16450/16550
> data sheet lists the default state of all registers except the Divisor
> Latch Register, which is the most important one for my application.
> It would be nice if I could simply power it up and strobe it when
> data is ready.
>  
> Maybe I should be looking at the 65xx family?
>  

Check into the Intersil/GE/Harris IM6402.  Configuring the part is done
by pulling pins high or low.  You'll have to provide an external 16x
clock.  Jameco sells this part for $3.75.  Its in a 40 pin DIP package.

Mark.
From: scottcr@wkuvx1.bitnet
Newsgroups: sci.electronics
Subject: Re: RADAR, RADAR ECM, and RADAR ECCM
Date: 26 Jan 93 18:40:59 GMT
Organization: Western Kentucky University, Bowling Green, KY

In article <careyj.727992636@spot.Colorado.EDU>, careyj@spot.Colorado.EDU (CAREY JOSEPH M) writes:
> np4@prism.gatech.EDU (Nick Pomponio) writes:
> 
>>The ECM device can be a simple repeater applying amplitude modulation to
>>the received signal. The AM frequency would be a function of the actual
>>velocity, the desired (deception) velocity, and radar signal wavelength.
>>Simple AM will produce two false velocity "targets"; the undesired one
>>could be supprssed by using a single sideband AM scheme.
> 
>>-- 
>>POMPONIO,NICHOLAS A
> 
> Okay, in theory I'll buy this, but lets see how it would work in
> practice.  You'd need to detect (very quickly) the signal, have some
> kind of a system wired up that would determine how much frequency
> (i.e. apparent doppler) shift to apply, and retransmit that signal
> (presumably with something that radiates independently of phi, like
> a dipole).  Further, you would need to make sure that you would not
> detect the signal that you would be transmitting, which is only
> a few hundred Hz (if memory serves we're talking about 30 Hz/mph,
> but I could be wrong) off the one you received, or your repeater would
> lock up.  And keep in mind that you'll be transmitting significantly
> more power than that which is received.
> 
> Yeah, I'll believe that it can be done.  It would even provide some
> interesting engineering challenges, but this strikes me as the kind
> of problem people solve for the fun of solving it, not because they
> really need ECM for their CAR (an F-16, yeah, but not my Plymouth).
> Also, to design this properly, you would need some pretty expensive gear.
> 
> Just a thought.  I'd sure like to see the results somebody else comes
> up with, but for me this reminds me of hacking computers -- an interesting
> problem that I don't want to spend too much time on.
> 
> 
> Sure is an interesting discussion, though.
> 
> Joe Carey
> joe@lobos.colorado.edu
> 
O.K. how are we gonna do this?  A linear transponder with (30 hz /mph
upconverter?);  Problems with in/out isolation.
 Maybe since we really
don't need a truckload of transmit signal (the radar unit is seeing
1 / (it's signal * 4PI * dist to car^2 * refl coef * dist back^2)
so if we retransmit say +10 dBm into a horn with 10 db gain that
should cover it.
A balanced modulator would have to be used for mixing as the signals
would be too close in frequency to filter; but the image being present
may give us trouble too (does the radar care if it's "coming or going?".
I am going to guess that
two horns facing forward spaced say two feet apart are going to have
about 40+ dB isolation, so this limits the throughput gain (again since
the freqs are too tight to filter),  What about polarization?


-- 
Chris Scott,  C/E Public Radio,  Western KY Univ,  (502) 745-3834
SCOTTCR@WKUVX1.BITNET      fx off: 745-2084     fx hm: 781-1232  
Newsgroups: sci.electronics
From: laird@pasture.ecn.purdue.edu (Kyler Laird)
Subject: Re: computer control of stepper motors
Organization: Purdue University Engineering Computer Network
Date: 28 Jan 93 02:02:54 GMT

Popular Electronics, June 1992, page 41.  "A PC-Based Stepper-Motor
Controller".  It's essentially four optoisolated NPN power
transistors hooked up to the parallel port.

--kyler
From: mark@deepspace.ucsb.edu (Mark Lim)
Newsgroups: sci.electronics
Subject: STD-->SCSI manufacturers
Date: 26 Jan 93 19:57:43 GMT
Organization: Astophysics-UCSB

Does anyone know the names and phone #s of STD manufacturers who make SCSI 
controllers that use the full interrupt 13 protocol and the AMPRO/SCSI 
interrupt 13 extensions? E-mailwould be appreciated.  Thanks.

Mark
From: np4@prism.gatech.EDU (Nick Pomponio)
Newsgroups: sci.electronics
Subject: Re: RADAR, RADAR ECM, and RADAR ECCM
Date: 27 Jan 93 04:21:51 GMT
Organization: Georgia Institute of Technology

Before I get started, let me state that my interest in this discussion is
purely in generic radar jamming techniques such as those used in military
applications and not in defeating police radar...

In <1993Jan26.124059.5230@wkuvx1.bitnet> scottcr@wkuvx1.bitnet writes:

>O.K. how are we gonna do this?  A linear transponder with (30 hz /mph
>upconverter?);  Problems with in/out isolation.

A straight repeater would probably suffice, unless the radar has leading
edge tracking.  Depending on the radar, a "passive" electro-mechanical 
method can be viable.

> Maybe since we really
>don't need a truckload of transmit signal (the radar unit is seeing
>1 / (it's signal * 4PI * dist to car^2 * refl coef * dist back^2)
>so if we retransmit say +10 dBm into a horn with 10 db gain that
>should cover it.

In general, the ratio of jammer signal power to radar return signal
power varies as the inverse square of the range to the radar.  Thus, the
power requirements must take into account the ranges over which the
jammer needs to operate, as well as the other factors you mention.

>A balanced modulator would have to be used for mixing as the signals
>would be too close in frequency to filter; but the image being present
>may give us trouble too (does the radar care if it's "coming or going?".
>I am going to guess that
>two horns facing forward spaced say two feet apart are going to have
>about 40+ dB isolation, so this limits the throughput gain (again since
>the freqs are too tight to filter),  What about polarization?

For a narrow-band system (where the frequencies of interest are concentrated
in a very narrow band), isolation problems can sometimes be solved by "tuning"
the antenna installation.  In fact, an RF circulator used with a single
antenna would probably provide ample isolation.

As far as polarization, it depends on what you had in mind.  One idea
is to use a single, dual polarized antenna in place of two antennas; 
unfortunately, I believe that the port-to-port isolation is less than
40 dB.  Another issue is polarization jamming.  That is an involved
subject in it's own right.
-- 
POMPONIO,NICHOLAS A
Georgia Institute of Technology, Atlanta Georgia, 30332
uucp:	  ...!{decvax,hplabs,ncar,purdue,rutgers}!gatech!prism!np4
Internet: np4@prism.gatech.edu
From: iah@dmu.ac.uk (Andy Humberston)
Newsgroups: sci.electronics
Subject: Filter design
Keywords: filter graph
Date: 22 Jan 93 12:01:44 GMT
Organization: De Montfort University, Leicester, UK.

A colleage of mine is interested in locating a program to assist in filter
design with graphical response.

Thanks



-- 
 ------------------------------------------------------------------
|     Andy Humberston, IT Services, De Montfort University, UK     |
|  Tel: +44 533 577159  Fax: +44 533 577170  EMail: iah@dmu.ac.uk  |
 ------------------------------------------------------------------
From: kludge@grissom.larc.nasa.gov (Scott Dorsey)
Newsgroups: sci.electronics
Subject: Re: DC to AC on large scale???
Date: 27 Jan 1993 15:40:38 GMT
Organization: NASA Langley Research Center and Reptile Farm
NNTP-Posting-Host: grissom.larc.nasa.gov

In article <C1HG4I.EG4@ms.uky.edu> msunde01@mik.uky.edu writes:
>
>Wouldn't using motors and generators cause a big drop in efficiency??  It  
>seems to me that a lot of power would be wasted in converting the  
>electricity to mechanical power and back . . ..  But then I suppose that's  
>exactly what gave somebody(-ies) the idea of doing it with silicon ??

Yes, that's why M-G sets aren't too popular anymore.  You can get up to
eighty percent efficiency at peak load, but the problem is that with a load
that varies considerably, a set designed to handle the peak load will be
extremely inefficient when less power is required.
--scott
From: bills@inqmind.bison.mb.ca (Bill Shymanski)
Newsgroups: sci.electronics
Subject: Re: DC to AC on large scale???
Date: Sat, 23 Jan 93 21:58:37 CST
Organization: The Inquiring Mind BBS  1 204 488-1607

slmdj@cc.usu.edu writes:

> While visiting my uncle in Calif. over Christmas break, he posed a question f
> me... Just so I have an answer for him (and myself too... It's an odd one)
> could someone help me out???
> 
> He is an assistant city engineer for Adelanto, CA, and told me that the way
> their power is distributed to a large substation is Direct Current!  He said
> that the DC is then 'phased' or 'converted' so that there is a three-phase AC
> line to the city distribution grid.  Neither of us have any idea how this cou
> be accomplished at such power levels (an entire valley, I think!)
> 
  Right now the lights and computer here are being run by a whacking
great large DC to AC converter system; in this part of the world, we
generate electricity in the far North at 60HZ AC, convert it to DC,
ship it 800 km south, and re-convert to 3 phase 60 HZ 230KV, which is
fed into the regular grid.  I believe total converter capacity in the
province is something like 2000 megawatts.  Never heard of DC to
AC converstion being used at the "municipal" level but I suppose it
could be done - seems a little unlikely, but two neighbouring
grids are sometimes interconnected by a back-to-back AC/DC/AC link
for good reasons. 
   Bill

bills@inqmind.bison.mb.ca
The Inquiring Mind BBS, Winnipeg, Manitoba  204 488-1607
From: rose@bucknell.edu (philip rose `94)
Newsgroups: sci.electronics
Subject: Re: DC to AC on large scale???
Date: 22 Jan 1993 16:55:59 GMT
Organization: Bucknell University, Lewisburg, PA
Distribution: world
NNTP-Posting-Host: canopus.cs.bucknell.edu

In article <1993Jan22.134237.13381@waikato.ac.nz>, phys2108@waikato.ac.nz writes:

|> One way I believe they can do it is by using the dc to power a motor, which
|> then drives an ac generator.
|> Geoff.

NOOOOO  WAAAAAY!!!

This is done with power electronics,  no motors or generators are involved.

-------------------------------------------------------------------------------
Phil Rose
rose@coral.bucknell.edu
Newsgroups: sci.electronics
From: Mike Diack <mike-d@staff.tc.umn.edu>
Subject: Re: Starting a mercury lamp
X-Xxdate: Wed, 27 Jan 93 07:39:57 GMT
Organization: persian cat & carpet co.
X-Useragent: Nuntius v1.1.1d7
Date: Tue, 26 Jan 1993 18:31:21 GMT

In article <C1FvCx.6y8@max.physics.sunysb.edu> ,
danube@max.physics.sunysb.edu writes:
>   Hello again.  More problems with my current research.  I need a UV
>source.  I have a used Mercury lamp, said 250W before I took the envelope
>off.  Inside is a quartz tube with two electrodes sticking into each
>end and Hg blobs on the sides of the tube.  There is no filament between
>the electrodes in the ends as in the ususal flourescent bulbs.
>   On one end, the two electrodes are connected to the AC via a 15K (?)
>resistor, i.e. hooked up like a little glow lamp with a current limiting
>resistor.  The other end is simply connected to the AC, through what
>was a filament of some sort before I evaporated it.  See the diagram
>below.
>    My question is, how is this lamp supposed to work and how can I
>get it going without blowing fuses? 
(nice ascii diagram deleted)
Just went through this little excercise last week - yes, you do indeed
need a ballast : in uncivilised (110volt) countries, this consists of an
autotransformer+choke combination, and is found in "security light"
fittings (weighs a heap) costs about $25 for the whole kit&kaboodle.
Be very very careful of that quartz tube - it is under pressure and
blows up with a helluva bang if abused. Never touch it with fingers.
The third electrode produces an initiator arc. In 230v countries, a
simple choke is sufficient. Without ballast, fuse blowing is inevitable.
Now if some cunning person could invent an electronic Hg vap ballast
cheers,
Mike.
Newsgroups: sci.electronics