Intentional radiator that is narrow band but rather
energetic.
Is there any frequency I can set this transmitter at in
this low frequency range and not accidentally step on a
restriction.
Vaguely remember some military bands down there that forbid
*any* transmitters down there, but can't find
Does anyone have experience in this band?
Or, have URLs to find limits and required characteristics
to operate in this band?
Robert
-
This message is from the IEEE Product Safety Engineering Society
emc-pstc discussion list.Website: http://www.ieee-pses.org/
To post a message to the
Andrew,
My firm has the technology to make optically transparent
magnetic shield. Optical transparency is better than 65%.
Costs relate to the requirement of how much
field of view
reduction of field
Please contact me directly, off the group.
- Robert -
Robert
Alas, all my vintage reference books are in storage.
As I recall, B refers to lower frequency capability and/or
finer BW resolution, like from 30Hz BW down to 10Hz BW
Simply has extended lower ranges.
- Robert -
On Tue, 25 Nov 2003 08:38:30 -0800
Pettit, Ghery
My vote..
Passive means to modify the field, this includes harmonic
content.
Active means use the field to generate new frequencies, as
though a battery were attached.
- Robert -
Robert A. Macy, PE .. m...@california.com
408 286 3985 . . . .. . . fx 408
From vague memory...
there was some work done by Don White (?) that shows tables
of this type of improvement. Full of practical data and
information.
- Robert -
On Mon, 17 Nov 2003 15:21:54 -
Jeff Chambers j.chamb...@ndirect.co.uk wrote:
I have been asked to comment on
Isn't it fraud to sell an item that does not meet spec? As
in, the vendor says the product is compliant when it is
not.
Don't all the customers then have a legal recourse to
return any/all product?
Doesn't policing the policy of compliance then become a
non-governmental function?
As far
From Dave Cuthbert's comments to me regarding a 1/4
wavelength dipole; he said that the current moves down the
rod as the rod becomes thicker, which implies that the
current distribution absolutely determines the effective
length. Was that effective length or tuned length? hmm
However, the
David,
Just did a search in Rich's Northern California Directory
for both air and modem which showed many companies, but
no results.
Also searched through Reference USA for *any* firm with
modem in their name, again many companies, but no
results.
If a company has been around for a while and
Message -
From: robert Macy
To: GARY MCINTURFF ; emc-p...@ieee.org
Sent: Friday, October 10, 2003 12:01 PM
Subject: Re: Corrosion tests - NEBS or Milspec
acceleration factors?
Gary,
From experience with security systems only close to
the
seashore (approx 2 miles away
Gary,
From experience with security systems only close to the
seashore (approx 2 miles away) it is best to *NEVER* have
any of the metal parts under stress/tension, else the
corrosion rates are incredibly accelerated.
The particular stainless steel part had been tested real
time in worse
Does someone out there have a PSpice model for a 1/4
wavelength antenna? 433.92MHz
Something that I can change to reflect diameter of the rod,
detuning, etc.
Or, do you know someone who has such a model?
Need it fast, please.
- Robert -
Robert A. Macy, PE ..
Scott,
How much wire is buried in the wall between the GFI and the
outlet that doesn't cause the problem?
Does the addition of an extension cord between the present
outlet and the shredder calm it down?
Do you have metal conduit? If so, you have a small filter
through your AC mains to the
Michael,
Back when I used to design coin operated games we had a
problem with intentional ESD doing damage to the
electronics.
Turns out, that ESD would, every now and then, give a free
game. Being rewarded with free games, they quickly learned
a damaging ritual - the kids would link arms,
Sounds like you just described the triboelectric(sp?)
effect and teflon insulation has one of the highest
electron work functions you will find.
Mechanical motion causes a separation of the insulation
from and along the conductor. That mechanical separation
causes a GUARRANTEED charge
Kapton comes to mind.
- Robert -
On Tue, 12 Aug 2003 11:55:25 -0600
drcuthb...@micron.com wrote:
I need a sheet of plastic that goes between a PCB and a
metal enclosure. This is to make a creepage spec. What
plastics are good for this? Will polycarbonate be
suitable and have a
Muriel,
Congratulations!
Is your thesis in English? If so, is there a location to
make it available for download? I'm sure many would be
interested in it.
- Robert -
On Mon, 11 Aug 2003 16:19:58 -0300
Muriel Bittencourt de Liz mur...@eel.ufsc.br wrote:
Hello
Simple eqn to remember
(2
skin depth = sqrt ( -- )
( w * u * sigma
w is radians per sec; or 2 pi f, with f in Hz
u is permeability . or . u rel * u free space
u free space is 4 pi 10-7
sigma is conductivity in S/m
all MKS units so
Paul,
Forgot to mention, one company years ago added their own
maximum width dimension of less than 30 inches so the boxes
could be put on a two wheel truck and easily wheeled
through a standard door!
- Robert -
On Tue, 29 Jul 2003 15:41:54 +0800
Paul Chan ncc...@tuvps.com.hk
Paul,
Sample shippers:
http://www.ups.com
At UPS website could not find any numbers, only
definitions.
http://www.fedex.com
At the FedEx website could not find any weight
restrictions, but did find Maximum length plus girth* per
piece is 300 inches . where *Girth = 2(Width + Height)
Interesting observation. You said hum gets louder.
Implying hum is already there. What kind of phone?
Is it only that one telephone instrument?
Only occurs when LEDs are near the instrument, not near the
phone lines with the phone in another location?
Is the effect more pronounced at
In case you have difficulty finding a strong enough field,
there is a company in St. Louis that makes a medical device
that creates 3D fields strong enough to rip a piece of
metal around inside the brain under computer control for
Parkinson surgery.
Their fields are in excess of 1 to 3 tesla,
John,
If you buy a GPIB card for your laptop *and* your analyzer
has the GPIB interface *and* you get your analyzer's
software manual, you can learn and write all the software
you need for your project in less than 2 hours.
Ok, ok, more like 6 hours, but still
-
Derek,
Most of the PS manufacturers I've dealt with use passive
dummy loads or quiet active loads. These very handy
quiet active loads provide programmable loading, BUT IN NO
WAY SIMULATE THE SUPPLY'S ACTUAL USE. In other words, how
many quiet loads do you power? Almost every load is a
micro
I use 3, with 10 as worst case.
- Robert -
Robert A. Macy, PEm...@california.com
408 286 3985 fx 408 297 9121
AJM International Electronics Consultants
101 E San Fernando, Suite 402
San Jose, CA 95112
-
Doesn't Excel work for this?
If not, I use a simple one called Grafdemo.exe which is
best for plots up to 150 data points *and* has curve
fitting SW for smooth displays and approx formulas.
Or, Computer Calculus 4.0 CC4 which plots 2D and surface
plots
CC4 has good presentation of 2D
Most spectrum analyzers don't do very well with a single
event. The repetitive waveform needs to be there to be
operated upon.
- Robert -
Robert A. Macy, PEm...@california.com
408 286 3985 fx 408 297 9121
AJM International
Interference from an adjacent/inband radiating source is
likely to cause the receiver's AGC circuitry to limit the
incoming RF signal to the point where the signal you're
trying to receive gets buried in the system's noise. Or,
the interfering signal is of sufficient magnitude so as to
simply
Don,
It is my understanding that physical switch contacts are
cleaned with current - and use.
It is probably ok at the lower signal levels since from
time to time you're running the higher levels through the
switches.
Is there someway you can switch and then verify contact?
If GW, wouldn't that voltage be more like 600KV/m, or at
least 30KV/m?
- Robert -
Robert A. Macy, PEm...@california.com
408 286 3985 fx 408 297 9121
AJM International Electronics Consultants
101 E San Fernando, Suite 402
San Jose,
To me, all this regulation can be synopsized:
Electronics shall not put out stuff - conducted or radiated
Electronics shall not be upset when stuff comes in -
susceptibility to conducted or radiated.
Difference in attitude between US and elsewhere:
It is my understanding that in the US
Being a past employee of HP and having met David Packard and Bill Hewlett
(just as the HP-35 calculator was coming out), it was with great sadness I
watched as the management team headed by Carly F effectively dismantled
everything they had built and stood for despite and in front of Bill's son.
Ian,
Contact me off line and I will share with you the SW tools (free on the
internet) that I use to do these calculations.
The first is an antiquated tool that runs on DOS called Computer Calculus
4.0, or CC4 I like it because it's powerful but easy to learn and retain.
The second is a 2D
Do you have the liberty to share your report - or details and results with
the group?
- Robert -
Robert A. Macy, PEm...@california.com
408 286 3985 fx 408 297 9121
AJM International Electronics Consultants
101 E San Fernando,
Dear group,
A fabricator of shell and tube heat exchangers located in Stafford, Texas
has a requirement for a California PE to perform a structural design check
on supports on two vessels that will be erected at the Shell Oil Plant in
Martinez, California.
Could you recommend a California PE?
Andy,
About 4 years ago I bought a book called something like Programming Guide
for the ... from HP which cost around $20. Not sure if it was for this
model or not, but watch out. Their system had the wrong part number and I
got some unrelated book and it took another 10 days to get the right
...@verifone.com
To: 'Robert Macy' m...@california.com; emc-p...@ieee.org
Sent: Monday, August 12, 2002 12:52 PM
Subject: RE: Need copies of specs addressing ISM bands in Europe
Try the following URL.
http://www.ero.dk/
Technical Staff
Senior EMC Engineer
William Morse NCE
Phone 916.630.2540
Apologize if duplication of question here.
Is there a website to get a copy of the European Community's rules regarding
ISM bands similar to FCC Part 15.245-9?
- Robert -
Robert A. Macy, PEm...@california.com
408 286 3985 fx 408 297
The people who supply these inbedded filter connectors, Regal Electronics,
can answer this and more.
- Robert -
Robert A. Macy, PEm...@california.com
408 286 3985 fx 408 297 9121
AJM International Electronics Consultants
619
Still use KHz
For me it's a logical carrier over from
small letter = small value
capital letter = large value
mOhm means milli Ohm NOT mega Ohm
mHz is milliHertz
KHz is kilo Hertz (note magnifier is larger than one)
MHz is megaHertz
and so on
Scott,
Not knowing how your system is exactly built makes it difficult to second
guess the lightning.
However, here is one way to protect your amplifiers: Move the protection
interface out to the edge of your building. Use rod located there with all
referenced to ground. At this same
No
- Robert -
Robert A. Macy, PEm...@california.com
408 286 3985 fx 408 297 9121
AJM International Electronics Consultants
619 North First St, San Jose, CA 95112
-Original Message-
From: Doug McKean
Then why would a 10 A surge change their characteristics?
Unless it cracks it?
- Robert -
-Original Message-
From: Robert Wilson robert_wil...@tirsys.com
To: Robert Macy m...@california.com; emc-p...@majordomo.ieee.org
emc-p...@majordomo.ieee.org
List-Post: emc-pstc
He may have magnetized it. Degaussing with one of those Radio Shack
thingies would probably brought it back. Can he try it again?
- Robert -
Robert A. Macy, PEm...@california.com
408 286 3985 fx 408 297 9121
AJM International
.
- Robert -
-Original Message-
From: Bill Ellingford bill.ellingf...@motion-media.com
To: 'Robert Macy' m...@global.california.com; emc-p...@majordomo.ieee.org
emc-p...@majordomo.ieee.org
List-Post: emc-pstc@listserv.ieee.org
Date: Monday, May 13, 2002 1:56 PM
Subject: RE
408 286 3985 fx 408 297 9121
AJM International Electronics Consultants
619 North First St, San Jose, CA 95112
-Original Message-
From: Bill Ellingford bill.ellingf...@motion-media.com
To: 'Robert Macy' m...@global.california.com; emc-p
Bill,
Thanks for the site.
Went there and found the same formula and constant I use.
For copper, Temp Coeff = 3.9 x 10-3
Then I clicked on table of coeff and there was a very long list of
materials, but the temp coeff of copper there was 6.8 x 10-3 ???!!!
Any ideas for this disparity?
Ned,
Not familiar with this K term. For straight resitance changes in
transformers, we always used 0.0039 per C. Does K somehow include contact
resistance, not just bulk resistance?
This is definitely the time to measure it.
Environmental chamber at -50, 0, 50, 100, and 150. Make your own
Slight adjustments
Part I http://www.pcdmag.com/mag/archives/OEG20010928S0122.html
Part II http://www.pcdmag.com/online/redux_0701_esd.html
- Robert -
Robert A. Macy, PEm...@california.com
408 286 3985 fx 408 297 9121
AJM
Amund,
I believe it's a law in the US that all products be labeled with their
country of origin.
- Robert -
Robert A. Macy, PEm...@california.com
408 286 3985 fx 408 297 9121
AJM International Electronics Consultants
Years ago in ultrasonic echocardiography instrumentation (the ultrasonics
analog is a wide band receiver listening in the 1-10MHz region down to less
than 10uV, so the digital had better be quiet!) which used a bit slice
architecture system containing Schottky logic with a clock of 20MHz for
Ed,
Thank you. Especially the part blaming Woodgate.
My grandfather's name was Fay (son of Irish immigrant) and I always wondered
at the origin of that name.
- Robert -
Robert A. Macy, PEm...@california.com
408 286 3985 fx 408 297 9121
horror would be examples of the
gotchas I was looking for.
- Robert -
-Original Message-
From: peter.pou...@invensys.com peter.pou...@invensys.com
To: Robert Macy m...@california.com
List-Post: emc-pstc@listserv.ieee.org
Date: Tuesday, March 19, 2002 8:23 PM
Subject: Re
Group,
What are the relative merits of the various logic families HCT, HC, AC, ACT
with regard to generating RFI?
I remember one time we replaced an HCT which made more noise than Schottky
TTL due to an internal overlap in the switching causing a power rail
shorting spike.
I'm sure by now that
Doing high voltage power supplies we found we always got in trouble using
20,000 V/in and things worked well when we kept below 10,000 V/in.
Metric that's 790 V/mm and 390 V/mm
This was free air and not some kind of pointy structure.
- Robert -
Robert A. Macy,
Did you take a look at the people who make traffic light controllers? , and
the magnetic sensor people?
If you can't find something, I'll see what's in archives around here. Know
nothing related to your needs, just some of the players' names.
Also, you'd be amazed the information you can get
Recommend you get a copy of Westinghouse Lighting Handbook
In one table they show lumens output for various fluorescent lamps with
current and volts input required.
for the Preheated
des.len curr. vol. *pwr lumens *lumens/watt
4W 6 0.132 32 4.32 115
Jim,
You touch on an important issue concerning a fuse - just how does it blow?
Years ago I discovered by accident that fuses were designed with some
remarkable properties, when we had to make our own transient generator to
verify some telcom equipment's compliance to a BABT power supply
Chris,
Using a PCB layer as an RF shield. Don't forget you probably have that PCB
layer cut into swiss cheese with vias, unless you used blind vias.
Background:
A microstrip trace will radiate off the board a certain amount - makes sense
since part of its
Our experience with gas discharge tubes was that they worked according to
spec in the lab. fired perfectly around 400V like they're supposed to, but
down inside of the PVC oil tank holding the 150KV isolation transformer they
liked to fire at 600V+
Guess they needed photon energy to make the
Derek,
Yes, do it all the time. As long as you don't get into saturating any
cores, you can pretty much use lumped models and none of the nonlinearities
associated with core material.
Don't forget to include your AC mains cable. It's a trifilar wound
transformer. A Belden AC cord looks like
Tony,
When we had to test a 100MHz video two board system, weaknesses in grounding
structures of the PC's became extremely evident. Two stood out as the best
(best internal motherboard grounding) Gateway (best) and Dell (very close 2nd
best). No other PC's yielded a compliant system. [ Even
That's Tesla, which is a weber per sq meter. It is a measure of the B
field, flux per area. If you're English, 1 tesla is 10,000 gauss.
I don't believe those numbers. We have light rail train go by here which is
powered by 600Vac (I believe it's 600 Vac) I haven't seen the fields from
the
Agree, worthwhile.
All the newspaper articles in the Career section of the newspapers say that
after being laid off to take off a few weeks, gain bearings, then look for
your new position. I totally disagree. I say take 20 minutes, shake your
head, and go for new places as agressively and
Hmmm...measured with a current meter, then measured with a wattmeter and got
different answersHarmonics out of phase? contain no power?
- Robert -
Robert A. Macy, PEm...@california.com
408 286 3985 fx 408 297 9121
AJM International
I'm going to say British pass on the left because the jousting pole is
usually held by right handers.
Sailors pass on the right, yet don't know the origin of that. Maybe the
sailing tradition started a propensity to pass on the right for colonists.
Automobiles in the US are made so the driver
It is my understanding that the conversion factor converts the voltage
reading on a 50 ohm receiver to the amperage reading directly. In other
words, 1dbuV *is* 1dBuA and already takes into account the 50 ohm input
impedance.
Sadly, all this was written before advancements in electronics
Perhaps, it merely interfered with the sensor electronics, not the true
magnetic field that was being sensed.
- Robert -
Robert A. Macy, PEm...@california.com
408 286 3985 fx 408 297 9121
AJM International Electronics Consultants
Great, Now we have to start adding information on the sales brochure, like As
the purchaser of this product places this product into service said purchase is
forming a licensed arrangement with the vendor to not hold said vendor culpable
for all uses and potential misuses of this product
I offered to forward this to the emc group for help.
Please answer directly.
- Robert -
Robert A. Macy, PEm...@california.com
408 286 3985 fx 408 297 9121
AJM International Electronics Consultants
619 North First St, San Jose, CA
Hear, hear.
It may have been hand waving but I always assumed that test sites never
correlated very well (although their calibration curves do) because the
actual radiators one is measuring are strange and not well controlled
impedances like an antenna. The sources can be low or high impedance
Wow! I've been telling clients that even a Beta test is allowed, as long as
absolutely no revenue is derived from it. Can't sell it. Can't rent it.
With no revenue, it is an exhibition, a test.
Is this wrong?
- Robert -
Robert A. Macy, PEm...@california.com
NoiseFigure new
= sqrt ( ( NF1^2 - 1 ) + ( NF2^2 - 1 ) + ( NF3^2 - 1 ) + ... + 1 )
where all noise figures are ratios and referenced to a
single location.
A few points:
1 Definition:
Noise Figure is the ratio of increased noise in a system above the expected
level of
Just a reminderalways make certain that no signal gets in to saturate,
or even start to overdrive, your amplifier at frequencies you're not looking
at.
- Robert -
Robert A. Macy, PEm...@california.com
408 286 3985 fx 408 297 9121
Low frequency conducted noise is usually generated by the periodic demand on
the energy storage cap (greatly, greatly affected by esr). This noise is
differential and no y-cap (unless it's so large it becomes a killer size,
and then not really) will stomp on it.
Your first problem (conducted
Did you see Regal Electronics? They make filtered RJ45 connectors
If not, try
Regal Electronics 408 988 2288
4251 Burton Dr
Santa Clara, CA 95054
might have a website around www.regalusa.com
A technical contact is Bill Kunz
- Robert -
Robert A.
Nick,
Contact this man, he has a lot of experience in the technical aspects of the
power distribution business.
Don Kelly
d...@home.com
- Robert -
Robert A. Macy, PEm...@california.com
408 286 3985 fx 408 297 9121
AJM
AR!!
I went there, read down through much, before it soaked in.
- Robert -
-Original Message-
From: Pettit, Ghery ghery.pet...@intel.com
To: 'Robert Macy' m...@california.com; James Collum
james.col...@usa.alcatel.com; emc-p...@majordomo.ieee.org
emc-p
In deference to the warning label on the peanuts bag. Some people have life
threatening allergies to peanuts and take warnings such as that and warnings
on cookies, etc very seriously. But then again, you'd think with the main
label Peanuts would be sufficient. Perhaps, someone is making
It is also interesting that 2mG limit closely approximates the emotional
one established through epidemiological studies.
Here in the Bay Area the field is around 50uT( 500mG )
It is my understanding that the magnetic field has been steadily declining.
From the time of Christ until now it has
Muriel,
Good thinking.
The answer is, depends..Keep in mind that at 30MHz the 1/4 wavelength is
still over 8 feet, so we're not really talking much about waveguides and
volumetric resonators.
Two areas to consider:
First, at the low frequencies most of the energy is simply not used *and*
Perhaps, it's time to utilize Alert instead of Warning for Class A
compliance information.
- Robert -
Robert A. Macy, PEm...@california.com
408 286 3985 fx 408 297 9121
AJM International Electronics Consultants
619
John,
Your point is well taken with regard to testing a unit while closely
matching the testing environment to the environment it will be used in.
However, we don't sell a lot of equipment to people who have 40 meters of
ground plane, either.
It is my understanding a reasonable false
Don't know if anybody responded, or not.
But first I would change your interface to include analog signals (I firmly
believe in never blinding the computer to what's really going on)
Second, the only IF temp meters I remember were made by Raychem, or such
back in the 70's. But they at least
North First St, San Jose, CA 95112
-Original Message-
From: michael.garret...@radisys.com michael.garret...@radisys.com
To: emc-p...@majordomo.ieee.org emc-p...@majordomo.ieee.org
Cc: Robert Macy m...@california.com
List-Post: emc-pstc@listserv.ieee.org
Date: Thursday, October 25, 2001 5:52
fx 408 297 9121
AJM International Electronics Consultants
619 North First St, San Jose, CA 95112
-Original Message-
From: Dan Kwok dk...@intetron.com
To: Robert Macy m...@california.com; emc-p...@majordomo.ieee.org
emc-p...@majordomo.ieee.org
List-Post: emc-pstc
-Original Message-
From: Robert Macy [mailto:m...@california.com]
Sent: Thursday, October 25, 2001 8:50 AM
To: Roman, Dan; emc-p...@majordomo.ieee.org
Subject: Re: skinny power cords.
Just have to jump in here with personal experience:
In our bedroom we have a deLonghi radiator heater
No soldered connections. The arc was external to the plug between the
blades. Carbonizing and then cutting more carbon in the burn track.
Remember the arc was *between* the blades, there was no power going through
the cord itself.
- Robert -
Robert A.
Just have to jump in here with personal experience:
In our bedroom we have a deLonghi radiator heater which uses an extension
cord (high cost UL approved) heavy guage #12 wire to power it - when it's
used. This extension cord plugs into a multi outlet adapter, also heavy
duty UL approved. At
Hope you're using more than one sample. I've been bit by having the one I
brought to the lab not being in compliance. Anyway, make certain.
- Robert -
Robert A. Macy, PEm...@california.com
408 286 3985 fx 408 297 9121
AJM
20log(d)
time is linear, like voltage
not the square, like power, thus the 20log
- Robert -
Robert A. Macy, PEm...@california.com
408 286 3985 fx 408 297 9121
AJM International Electronics Consultants
619 North First St, San
Ok, ok.
For all those whose virus scanners spit up when seeing files with my
mnemonic names - upon request I'll send to you an unzipped version (about
60K total) with every file renamed with the extension *.txt. For example,
PRINT_02.BAT will be PRINT_02.BAT.TXT etc Then you can do with it
I got two NAV (Norton Antivirus) msgs back from the ieee.org that said my
attachment had a virus in it.
If so, please let me know, because there is nothing but text files (that I
know of) and a simple batch program in that attachment.
Very important that *IF* I have a virus, need to know !!!
Apologize for being off topic, but I've attached a printable calendar for
2002.
It prints out on 8 1/2 by 11 (for all the metric people) in landscape mode.
Very little clutter and has big squares to write in. If you have a DeskJet
500, you can print directly to it.
If not, use the text file
Sorry about this being so far off topic, but I don't know where else to find
the largest group of technology professionals who can answer this question:
How much water will flow out of a 3/4 inch pipe which is under 60 psi?
There is a restriction and the actual inside ID is around 7/16 inch.
My
Move the antenna further away. then use correction factors to calculate
what it would have been at the original distance.
Magnetic fields decrease as the inverse cube of the distance. So just apply
a correction factor to boost the amplitude back up. For example, twice
the distance away means
Sorry to post here but am running into a brick wall at trying to find out
something as simple as the resistivity and dielectric constant for skin!
Does anybody have a source? Need quick, please.
- Robert -
---
This message is
Chris,
Fluorescent tubes are noisy anyway, but the old passive ballasts are
starting to be replaced with active electronic ballasts. Those electronic
widgets actually run at frequencies down near what you're using.
Electrically they can be EXTREMELY noisy. The US has no real restrictions.
As
They will deliver less powerabour 50/60 of what you expect.
The power supplies in those ovens are quite inexpensive and use a single
rectifying diode. When the voltage gets high enough, the microwave bursts
on for a short time. Thus, if operated from 50 Hz instead of 60 Hz, the
power will
Did you find out what you need?
Somewhere around here I have the equations that closely approximate twisted
pair for 26 Awg and 28 Awg wire from DC to 10MHz. They were derived from
empirical modeling. You can make various approximations to simplify their
use.
That includes impedance, loss per
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