by: Larry Bloomfield & Jim Mendrala
Note - 060
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Andy Toms email@example.com
Comments on the Web site.
came across your web site during my efforts to gain some insight
into the transition to DTV/HDTV. It is interesting to see some opinions
that do not necessarily just pander to the desires of equipment
manufacturers, as is so common in most of the trade magazines.
Point to Ponder:
Poor quality unchallenging programming remains so, whatever the
definition, digital or analog.
Toms, Chief Engineer -- Studio Post, Edmonton, Alberta, Canada
From: Jim Waschura
Tech-Notes -- 059
Thank you to John
Luff of STI Digital for his remarks concerning committee work.
I have participated in SMPTE engineering committee meetings for
a few years now and no one asked me for my secret card before I
could participate. I just volunteered to work for the best
interest of the community, and to respect the practice of keeping
intermediate work confidential among the participants. There's
absolutely nothing "back room" about it; anyone who's
willing to work can participate. In particular, the committee
I work on has published specific questionnaires and requests for
information in trade journals to obtain industry input (and received
very little response, I might add).
I hope the acidulous level of correspondence can be squelched soon.
I doubt that it will be productive.
Waschura, SyntheSys Research Inc.
A. Luff Synergistic Technologies, Inc. firstname.lastname@example.org
The following are excerpts from an e-mail we received in response
to Tech-Notes 59. We were asked not to publish it. In
deference to the author, we have only shared part of this e-mail
as the author, John Luff makes some good points that need to be
mentioned. Since it is my opinions – Larry Bloomfield – with
whom he disagrees, I will take the liberty of making comment in
italics, surrounded by [ ]’s through those parts we have chosen
to print. In many respects, we are not that far off.)
I see (this)
as exceedingly complex and intertwined. [Agreed!]
ATSC does at
times act in ways that seem to those who are not involved to be
without adequate explanations. It is important to note that the
standards work is done by individuals who labor long and hard to
solve the problems they are handed, in the most appropriate manner
they can. [Agreed! And they are to be commended for
their Herculean efforts.]
The fact that
DVB seems to have "gotten it right" in the opinion of
some in our industry is in part because they started later and had
the benefit of close coordination with the research labs in Europe
who were developing COFDM and evangelizing its capabilities on both
sides of the Atlantic. Unfortunately for the US market they were
a little too late in developing a demonstrable system. [I
do not believe it is ever too late to look at better technology.
If that were the case, we might still be driving teams of horses
instead of cars.]
I find it particularly
interesting that broadcasters in general showed little interest
in the entire DTV proceeding until it came time to implement.
[This is a very true statement! Where were the broadcasters
when all this was being put together? They certainly have
always had a vested interest, but seem to have taken a rather cavalier
attitude.] Very few spent any time in the
ACATS or ATSC processes. It is regrettable that the best science
of 5 years ago is now proven to be at least suspect, but it was
not done in the dark, or by a rump committee that wanted to somehow
promulgate a travesty on the American consumer. [I don’t
believe any right-think person believes it was. It’s just
that something better is available now and the old should give way
to the new. The patches and band-aids don’t seem to be working very
You seem to
be crying out that you want to know what is being said and done...seems
to me that is not prior restraint, but lack of personal knowledge.
[Agreed it is lack of knowledge due to lack of disseminated
information. If ATSC, or any other standards making body for
that matter, put out progress reports saying what they were doing
and were they were in their deliberations, the air of suspicion
would certainly be dissipated.]
privacy statement is no different that a Non-Disclosure Agreement,
many of which I suspect you have signed, as have I, over the years
when working closely with manufacturers. [I disagree with
this. An NDA is to protect a company’s proprietary interest
and their developmental efforts. It is not an instrument to
keep the public from knowing about standards that will impact their
lives.] ATSC manufactures intellectual property, which
is in the public domain when finished. [It should be from
start to finish.] I cannot see why it is not within
the legitimate rights of ATSC to manage the dissemination of information
about things that MAY be done in the future any differently that
it is with the FCC, or for that matter GM or AOL. [The
FCC had better keep things public. GM and AOL are private
concerns and unless they are developing standards for all of us
to abide by, I don’t care what they come up with.]
contact the FCC and ask what they are doing in the OET about the
problems. I think you will find they have already said that VSB
progress is acceptable to them (loose interpretation by myself,
and poor science by them), but they are doing their own comparison
field tests now, as well as is MSTV. [If you read these
Tech-Note regularly, you will see where we have said that the FCC
is today a mere shell of a once well respected engineering organization
that has been so politicized that it bears little resemblance of
what it once was when we could depend on them to find the best ways,
out in the open, for broadcast industry standards of technology.]
It is my opinion
that stirring the public caldron will only make the introduction
of DTV slower. I suspect you do not share that opinion. [Perhaps
you’re correct, but I’d rather stir the public caldron than be saddled
with a standard that is second place. I never want to see
us take second place in anything, especially technical standards.]
seem to be afraid of what is being done TO broadcasting by parties
who you seem to feel are not involved in the craft. If you
attended even one meeting you would find that to be untrue. [Not
so. We can do a fine job of shooting ourselves in the foot
without any help from outside the industry.]
Why don't you
come into the tent for just a minute and see what is in there.
[I accept!] You would be required not to report to your
newsletter the contents of but one short meeting, the contents of
which would no doubt end up on (an internet) forum within hours
anyway without your complicity. [I cannot, nor will I ever
agree to keep confidential any standards setting sessions that affect
the entire industry and possibly the world. These are not
priority issues!] You may well find that you can make a contribution
if you try. Participation is available by dial in [Send me the
numbers.] so long as you agree to the privacy guidelines. [I’ve
addressed that and I will not play politics!] I think
you would find it worth your time, and of service more to the industry
than complaining without knowledge of what you are complaining about.
[I would be more than happy to contribute my time and efforts,
but I will not join in with anyone who must make public standards
behind closed doors. And by the way, Jim Mendrala doesn’t agree
with me on this, but understands where I’m coming from. Do
Dick Hobbs Dick_Hobbs@compuserve.com
Tech-Notes -- 059
thoroughly approve of your dismissal of John Luff's arguments. It
is quite clear that, with very few exceptions, groupings of learned
bodies have produced deeply flawed compromises rather than best
engineering practice. As the English proverb has it, the camel is
a horse designed by a committee.
wishing to tell you folks on the left hand side of the Atlantic
what to do, I cannot help thinking that, if there was rather more
public scrutiny of the FCC's workings, then perhaps it would have
taken more notice of the digital television experiences of us on
the right hand side of the Atlantic.
(writer and commentator on the application of broadcasting technology
as it relates to the viewing experience.)
Roy Trumbull - ENG email@example.com
I've been kidding
for several years that for DTV transmission we need the equivalent
of the old Simpson 260 multimeter to do basic testing. I've looked
at several systems that do detailed analysis of the digital signal.
But the sorts of information they collect would be what a system
designer or software developer needs. I just want to know if the
system is alive and has normal vital signs.
a recent SMPTE meeting, Joseph Nigro, the sales manager of Triveni
demonstrated a tool they've developed that runs on a laptop with
a receiver card. It captures a sample of the signal and then displays
the packets in multiple colors. TV services are in different shades
of green, audio packets are red, null packets are black, PSIP packets
are another color, etc.. You can click on a packet and find out
what's in it.
For example, clicking
on an audio packet gives a red waveform display that can be expanded.
The normal profile is stairsteps of data filling a buffer and then
a steep falling edge as the buffer unloads. We tuned in a station
that's acquired a certain fame for having a faulty encoder. The
profile was very different. There were fewer steps, a long plateau,
and then a drop. The display shows where your audio is relative
to the model of receiver buffers so you can avoid causing underflow
and overflow problems. Similar displays profile video.
short, I felt that this product would give you what you need to
know. I don't have a model number or a price, but I want one.
From: Bill Ruck
is something that all of you that are in the 1.0 V P-P world may
have an interest in.
The TIA/EIA has
proposed to reaffirm EIA Standard RS-250-B, Electrical performance
Standards for Television Relay Facilities without changes or updates.
This version of the standard was adopted September 1976.
The standard was
approved for reaffirmation by the TIA TR-14.10 Subcommittee on Electrical
Performance Standards for Steel Antenna Towers & Antenna Supporting
Structures. I've been told that they claim there was no interest
in modifying or updating the standard by the broadcast industry.
would expect that there might have been a few changes in TV since
you are interested in participating in the standard process, contact:
Zidek-Conner -- Standards Secretariat
Industry Assiciation (TIA)
Wilson Blvd., Suite 300
process is open to all interested parties.
Ruck, Chair -- Northern California Frequency Coordinating Committee
CBS Field Sequential Color System
CBS field sequential color system in its simplest form consisted
of a rotating color wheel of red, blue, and green filter segments
in front of a monochrome camera, feeding a black and white CRT receiver
viewed through a second rotating color wheel. The two wheels were
kept in phase synchronization, such that successive television fields
were viewed using identical color primary filters to that at the
camera. To overcome flicker, the field rate was increased 60 to
144 fields per second resulting in 24 complete color frames per
second. To compensate for the increased field rate within the standard
6-MHz channel, the lines per frame were reduced from 525 to 405.
A 29,160-Hz line rate resulted. This led to the basic incompatibility
of the CBS system: no standard monochrome receiver could present
an intelligible picture during the color telecasts.
had first broadcast its Field Sequential Color System as early as
28, 1940. Their 1949 Color System was the third field sequential
approach to be proposed to the FCC for adoption. They had suggested
that their field sequential standards be adopted in 1941 and 1946.
At those earlier times, with few black and white receivers in the
hands of the public, the adoption of the CBS system might have been
It is interesting
to note that today a 24p or 30p image can be transmitted and displayed
at 144 or 180 fields per second using Colorlink's (http://www.colorlink.com/products/switch/switch.html)
ColorSwitch. This is what we will be seeing in the near future
on some of the new displays that will be coming out shortly. (http://www.displaytech.com/).
Displaytech seems to be a leader in this area so far. They were
demonstrating field sequential at 180 fields per second and 30 frames
at the SID held at Long Beach, California back in May.
the 8-VSB – COFDM Pot Again.
Hardly an issue in
history broadcast has taken on such religions connotations, as has
the debate over 8-VSB and COFDM. Proponents of each appear
to be fighting with their dying breaths to either keep their ground
or at least gain equality, as the case may be.
When it was heard
that House Telecommunications Subcommittee
Chairman Billy Tauzin (R-La.) invited Sinclair to do a live, over-the-air
demonstration of 8VSB versus COFDM--competing digital TV modulation
technologies--at a hearing on digital TV scheduled for this month,
it was time to call Ken Johnson, the congressman’s spokesperson.
Johnson, said: "Obviously
there is a great deal of concern here on Capitol Hill about how
consumers may be impacted during the transition to digital.”
As a result, Congressman Tauzin held a public hearing on DTV standards,
and the transition to digital, not ten days ago.
There is little question
that the transition to digital has met with a multiplicity of unforeseen
obstacles; the robustness of 8VSB as compared with other modulation
techniques such as COFDM is only one of the more visible.
“We are going to invite engineers and broadcasters who support both
DTV standards (8VSB and COFDM) to testify,” Johnson said before
Now a matter history,
it appears that Congressman Tauzin wants HDTV and a band-aid for
the questionable 8-VSB. It came across to me as my son, when
speaking of the misdeeds of my 2-year-old grandson, “so he’ll get
over it.” My question is, in both cases, how do we live with
the situation in the mean time and what happens if he doesn’t get
Prior to the hearings,
Congressman Tauzin met recently with David Smith, President of Sinclair
Broadcast Group (SBG). Smith and the engineers from the SBG
have been vociferous proponents of COFDM as an alternative to 8VSB,
submitting a failed petition representing over 300 full-power broadcast
stations to the FCC on the very issue. Apparently Smith found
a receptive ear with the right Congressman. Johnson continues,
“and he (Smith) made a compelling argument that current standard
may preclude millions of Americans from getting effective digital
“Obviously that sent
up a red flag,” Johnson said, repeating what the congressman said:
“‘it’s time to show me’. So we've asked Sinclair, among others,
to demonstrate what a live, over-the-air signal would looked like.
If it's true, as they say, or it's true as they claim, that many
Americans will be looking at blank screens, I suspect you'll see
a lot of Congressman with blank expressions on their faces at that
hearing,” Johnson concluded.
There’s little question
that Sinclair has fought a strong, uphill battle. It seemed
like it was all over but the shouting when the FCC summarily dismissed
the Sinclair petition in February, but apparently Smith and company
had one more ace up their proverbial sleeve.
In a public statement
on the same subject, Johnson said: "Even though this
is a technological argument, our eyes may tell us a lot more than
our ears. That's why we want to have a public demonstration
during a Congressional hearing."
Referring to the
SBG/Smith visit, Johnson said: “They make a very compelling
argument that millions of Americans may be looking at blank screens.
If members are looking at blank screens, I think a lot of jaws are
going to drop,” Johnson warned.
certainly doesn’t hurt to have the Chairman
of the Congressional committee that signs the FCC’s pay checks in
your corner… Now all they have to do is make their point!
But did they?
From reviewing the various testimonies given, it is difficult, at
best, to determine what will become of all this. Between the
political/half-baked-scientific rhetoric, good old fashioned Washington,
DC BS (I don’t mean bachelor of science either) and detracting misinformation,
those who had something worthwhile to share were lucky to have been
seen in the spill from the misguided spotlights. I walked
away with the idea that 8-VSB was given just one more of many chances
to get its collective act together and then who knows. If
what is said: “broadcasters are simply trying to delay the transition”
is true, they sure got lots of help from the congressional hearings.
Where’s the lady?
I don’t think she’s even begun to warm up as yet, much less come
to the microphone. Remember, we still have the somewhat stalled
biennial review by the FCC. If fact cannot overcome
the shortcomings of what we now have, we may have gotten to the
point of diminishing returns when it comes to getting an alternate
technology for a modulation system.
Through all the skull
dungaree and Washingtonian intrigue, we will one day wake up to
find that we are not the only ones on this planet! World standards
are a must or we will be condemned to relive our history to the
tune of many pieces of latnum. I’ll never understand why all
that good hard earned, but wasted money never falls into my coffers.
I’m somewhat glad it doesn’t, because I like being able to sleep
at nights with both eyes shut.
History? I've got a few tales
From: Robert Lund,
Avenir Designs firstname.lastname@example.org
good to see someone who appreciates the legacy of the technical
development of this medium, which engulfs modern life. Plans for
a web site go round in my head, but daily life has a way of putting
it off to some hopefully near future date. I can't write my contribution
to history right here on a Sat. morning, but lemme give you an idea
of my connection with telecine et al.
When I left Bell
Labs to work at Teletronics in 1972, Armando Belmares-Sarabia and
Robert Lieberman did telecine transfers using an “automated” color
correction system custom-built. Metal tabs were clipped to the film,
which triggered the system during transfers to kick in the next
sequential set of corrections. Color parameters were stored in one
of 9 potentiometer banks, which were selected by thumbwheel switches.
You get the idea, a totally analog hardware solution. I got familiar
with PDP-11 minicomputers there and then, the basis of the early
CMX systems I was charged with maintaining and upgrading. So we
designed and built a computerized system to replace the old pot-based
suite, based around a PDP-11. Designed in concert with the end user,
Joe Bond, it was tailored to his needs, and stored data in a table
in core memory. It was a big moneymaking hit, and we built two more
systems for the facility. Sarabia's attorney got the thing through
the patent office (in spite of the fact that young, naïve me maintained
that it was "just a project, not a true invention"), and
a patent was granted in 1978, shared by Armand, Stan Chayka, and
myself young technician. Armando and Stanley took the patent and
formed their own company, eventually suing many manufacturers AND
customers during the 1980s as though he had the patent on computer-assisted
telecine color correction. Testifying at depositions against
my old boss on behalf of a consortium of manufacturers/defendants
in the 1980s was extremely interesting and rewarding.
you'd like to know more about this aspect of telecine history, lemme
know, and I can dig into my archives and provide many more details
and anecdotes. Great thing you're doing!
“So many good
ones, and so many bad ones; that's what you get for trying."
Dutch Schultz, last words
There’s no way telecine will go away in digital television or
HDTV. The fact of the matter is that most all HDTV material
on the air weekly, now, originates on film and is transferred to
HDTV by one of the Colorists from the telecine/post production part
of our industry.)
By: Larry Bloomfield
It was mid-Monday
morning, May 22, 2000, that the news wires began to buzz with a
story about a news incident that occurred in Southern California.
It was the kind of story that none of us in the broadcast industry
like to hear: one of our own was hurt while covering a news story!
It was a typical
Monday morning. Assignment editors were sending out newscrews
and minivans to begin putting together the stories that would appear
on their stations daily news fair. At about 9:40 that Monday
morning, photographer/technician Heather MacKenzie and reporter
Adrienne Alpert, arrived to cover
a Los Angeles police news conference in Hollywood on Santa
Monica Boulevard where they would join other news crews to report
on a story about child car seat safety. The assignment itself took
a backseat to the very unfortunate incident that was about to occurred.
As assignment editors
across the country became aware that something “hot” was unfolding,
they called up Telstar Six, One Delta and it was there that the
chilling story unfolded before their very eyes, bring a halt the
beehive of activities associated in their respective newsrooms while
they mused: “My God! That could have been us!” Unsteady
cameras showed what had happened and it was not what they had been
sent to cover, but rather what had happened to a news van and members
of their crew.
A KABC-TV news van
microwave dish had brushed a power line in Hollywood, burning reporter
Adrienne Alpert over 25% of her body. Adrienne Alpert is a well-respected
veteran of over two decades, who has covered stories from nearly
every venue in both the San Diego and Los Angeles markets.
After arriving to
cover the story, they apparently agreed that the location they had
first chosen to park was directly under the power lines, so they
moved to a location a few feet away. Nothing particularly unusual
about that, but the location chosen had a pronounced slope downward
toward the street, where they had just come from. Since
the van sat on a slope, the mast was listing from vertical. Eyewitnesses
say that the driver side of the van was within a foot or two of
being directly underneath a 34,500-volt service. Above those lines
were perhaps a dozen other lines carrying even higher voltage.
the truck MacKenzie called in to begin transmitting and steering
the dish to a relay site. Witnesses, including a couple of mechanics
working near where the two had parked, said they began yelling at
the two in the van from outside to “stop the raising mast.” A crew
across the street from KRCA, channel 62 started videotaping the
mast as it brushed the wires, while they too were yelling and waving.
Alpert decided to
get out of the van's passenger side doors. As Alpert stepped
out of the van, that completed the circuit from the 34,500-volt
line, arcing through the top of the parabolic dish to its inner
reflective mesh, its mount, down the aluminum mast, through the
van body and its door handle, through Alpert’s left hand, through
her body and out her right foot.
van was parked so near the building that the door apparently struck
the wall. A nearby drainpipe that appeared to be an air conditioner’s
condensate (water) runoff was seen in several after shots with a
large char mark where the pipe enters the steel mesh-filled stucco
wall. The pavement was wet where the water had been draining near
the front of the van. Whether Alpert stepped on wet ground is not
clear. It is believed that when the door hit the wall, the main
explosion apparently occurred.
to assist, but weren't sure whether they were clear of electrocution
danger yet. The mast came down from the wires rapidly; the seals
had failed. It wasn’t clear whether Alpert’s windpipes had
been burned or her diaphragm had been paralyzed, but she had trouble
breathing and asked for help.
The closed circuit
feed showed horrible burns on Alpert’s limbs where she had suffered
fourth-degree burns. Doctors have performed vascular surgery
to remove blood. The result of this injury has caused Alpert to
go through amputations of the left forearm and right leg below the
knee and had required assistance from a respirator. There
is no question that Alpert is glad that was the extent of her injuries
and just happy to be alive.
the van’s driver and technician, was not injured.
and not wanting to spawn misinformation, many insiders have been
reluctant to discuss the specifics of the accident. Nonetheless
in speaking to folks "on the inside" at KABC-TV, there
remain a lot of unanswered questions on her accident, and multiple
versions of the details of what happened, and why.
Despite that this
incident occurred in Southern California, it could have, and has
happened, all to frequently else were. Peter MacNaughton a
30-year-old photographer/technician on assignment from KGAN-TV in
Cedar Rapids, Iowa, while preparing for a live news report at Squaw
Creek Park in Marion, was shocked and burned just five days later
on May 27th, as he was raising the mast on a microwave news van.
The mast came in contact with an overhead power line that was carrying
115,000 volts of electricity. MacNaughton suffered burns over
25% of his body.
There is little doubt
that ENG crews all over the country have recounted these and other
events in their minds. Let he who is without sin cast the first
stone. One’s first reaction maybe: what was she THINKING about
to have raised that mast into that web of electrical lines? This
most likely would be followed by a second reaction: been there;
(almost) done that!
While the Southern
California press focused on the ENG antenna contacting a 34,500-volt
line, engineers know that two points of contact are necessary to
complete a circuit. There are still several unanswered questions:
Was Alpert "blown out of the van" according to some press
accounts, or did she deliberately bail out because of smoke and/or
fear of an explosion? Was there in fact an explosion as some
press accounts reported, or simply arcing? Exactly what did
Alpert (and the two other injured individuals) touch to draw electrical
current? It is tempting to say that Alpert stepped out of
an electrified van thereby completing a circuit to ground, but the
details may be more complex.
While some vans have
the mast deployment controls inside, others require the operator
to stand outside. The older, homemade vans from several years
back, and before, had controls inside the working area at the top
of the rack, so that an operator could engage the mast without ever
getting out of the van to look for obstructions. No roof window,
not even a floodlight was mounted at the bottom. Newer vans,
however, have the controls inside the rear door and a floodlight
shining up which can't be extinguished. An operator must get
out of the van, open the door, reach inside, and engage the air
valve upward. It was not clear which type KABC-TV van was,
but the incident occurred on a clear day in the middle of the morning.
locking the barn after the horse has runaway, it only took two days
for unions representing broadcasters and camera crews to call for
“an emergency meeting” to devise uniform safety standards for newsgathering
in the field. Union representatives said they were hopeful to meet
with stations no later than May 30 to begin establishing safety
guidelines. "We want all (stations) to follow a standard,"
said Gena Stinnett, president of National Association Of Broadcast
Employees and Technicians-Communication Workers of America (NABET/CWA)
Los Angeles area, Local 57. "No station should try to beat
another station to a story by cutting corners on safety," Stinnett
Not to be outdone,
the American Federation of Television and Radio Artists AFTRA) joined
Stinnett's union in calling for safety guidelines. According to
Gerry Daley, AFTRA local spokesperson, there are no “adopted” safety
standards for this kind of thing and the Occupational Safety and
Health Administration (OSHA) has no such guidelines for the broadcast
media. Our research (Broadcast Engineering) found well-documented
guidelines on this very topic.
The bottom line is,
there are a few hints as to the mechanics of the accident, but prudence
dictates that we await the authoritative reports. Once the
true facts are known, accident prevention programs can be implemented
and fine-tuned. This does not belie the old adage; an ounce
of prevention is worth a pound of cure. It is incumbent on
station managers and Engineering Managers to make certain that anyone
who operates an ENG van, truck, or mobile studio, that all their
staffs have been fully trained, educated, and understand fully the
dangers involved where overhead power lines, etc. are concerned.
This is a management must and should be documented in writing.
Refresher courses are less troublesome then attending a colleague’s
Safety is ALWAYS
the crew's responsibility, but a responsibility that must be SHARED
by station management. The crew MUST have the proper tools:
Adequate SAFETY DEVICES must exist and be checked regularly.
And PROPER SAFETY TRAINING must be provided regularly too, just
as it is for an airline crew. Then and only then can the workers
be responsible for doing their jobs safely.
largely the conclusions come down to TRAINING. Hardware issues are
far more limited and manageable.
your staff know:
1. what happens
when you park on a slope and raise a mast?
2. trees can
3. how to get
away from a suspected charged object?
4. what to
do when their GFI won't let their extension cord energize in a rain
5. what to
do when a safety issue seems to conflict with news gathering?
6. how to safely
rescue someone who is being electrocuted?
you have a training packette prepared, how well is it written? For
example, does it say: "you should have 10 feet of clearance
for every 50,000 volts on a line?" That’s meaningless! How
will your staff measure the voltage of the distant line and how
will they measure the distance?
a dedicated technician onboard prevent more accidents? Maybe. Surely,
this question will be dragged into any litigation regarding the
KABC-TV incident. Union shops like theirs, at one time, had a third
person dedicated to set-up and driving ENG vehicles. Unfortunately,
marginal safety loss has to enter into any equation regarding staff
Safety devices back
up trained humans, and trained humans back up safety devices.
When you have both components, you have an interlocking, synergistic
system that works.
that we want to put safety measures in place right away so that
these tragic accidents will not, or cannot happen again, at least
in the same way. It's for that reason that many engineers
and technicians are coming up with all sorts of schemes to prevent
this type of accident. It is equally as important; before
we over-engineer our professional practices and procedures we begin
with some basic questions. Is the "one-man band"
ENG crew basically unsafe? Is it unsafe sometimes, and safe
on other occasions? Who determines when it's safe and when
it isn't? There are similar concerns about transmitter engineers
who work alone in rather dangerous areas. Is there a relationship
between accidents in our industry and financial cutbacks?
The picture may indeed be larger than we realize. This will
never change the fact that accidents are very sobering events, happening
lightning fast with life-altering consequences.
additional information on ENG Safety and the two incidents reported
above, visit the following web pages:
LINE PRESSURE SENSOR
From: CGC Communicator
Larry Quick of KSDS
uses a Phartronics "pressure sensor interface" to convert
transmission line gas pressure into a DC voltage for remote monitoring.
The Phartronics PSI-V3 has 0.25% full-scale linearity, works with
pressures in the 0 - 14.5 PSI range and outputs 0 - 4.5 VDC in proportion
to the pressure. A wall wart powers the device, which is supplied.
Cost is about $200 and Harris and RF Specialists sell the units.
The company can be reached at email@example.com.
What kind of handy,
obscure and unique gadgets do you have around your transmitter plant?
Ron Gonsett -- CGC
Advances -- Faster Than
A Speeding Bullet!
You had better
believe it! If what scientists are claiming, there are a few
physics books that will have to be re-written. Until now,
we’ve all been told that nothing can go faster than the speed of
light, but as the song from Porgy and Bess goes, “It Ain’t necessarily
so!” The implications are mind-boggling: Using current thinking,
one interpretation would have light that will arrive at its destination
almost before it has started its journey. In effect, leaping forward
Dr. Lijun Wang and his colleagues, of the NEC research institute
in Princeton, transmitted a pulse of light towards a chamber filled
with specially treated cesium gas; before the pulse had fully entered
the chamber it had gone right through it and traveled a further
60ft across the laboratory. In effect the light existed in two places
at once, a phenomenon that Wang explains by saying it can be explained
by the wave nature of light.
details of the findings remain confidential, as the test procedures
have been submitted to Nature, the international scientific journal,
for review prior to their possible publication.
Needless to say,
this is causing quite a stir in the Physicist community. What
seems to be the key issue is that if light travels forward in time,
it could possibly carry information, breaching one of the basic
principles in physics - causality; the
principle of relationships between cause and effect, which says
that a cause must come before an effect. This would also shoot
some very big holes in Einstein’s theory of relativity which depends,
in part, on the speed of light be unbreachable.
said he could not give details but confirmed: “Our light pulses
did indeed travel faster than the accepted speed of light. I hope
it will give us a much better understanding of the nature of light
and how it behaves.”
Dr. Wang is apparently
not alone. In a paper published by physicists at the Italian
National Research Council, they described how they propagated microwaves
at twenty-five percent above the normal speed of light. The
group speculates that it could be possible to transmit information
faster than light.
Guenter Nimtz, of Cologne University, an expert in the field, agrees.
"The most likely application for this is not in time travel
but in speeding up the way signals move through computer circuits,"
experiment is the latest and possibly the most important evidence
that the physical world may not operate according to any of the
accepted conventions. In the new world that modern science is beginning
to perceive, sub-atomic particles can apparently exist in two places
at the same time - making no distinction between space and time.
Turok, professor of mathematical physics at Cambridge University,
said he awaited the details with interest, but added: "I doubt
this will change our view of the fundamental laws of physics."
that his experiments are relevant only to light and may not apply
to other physical entities. But scientists are beginning to accept
that man may eventually exploit some of these characteristics for
inter-stellar space travel. Maybe some of the things we’ve
seen on Star Trek are more science than fiction.
Tech-Notes are published by Larry Bloomfield and Jim
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