Copyright: 1996 - 2024
BSEE - KB3UON
RF Cafe began life in 1996 as "RF Tools" in an AOL screen name web space totaling
2 MB. Its primary purpose was to provide me with ready access to commonly needed
formulas and reference material while performing my work as an RF system and circuit
design engineer. The World Wide Web (Internet) was largely an unknown entity at
the time and bandwidth was a scarce commodity. Dial-up modems blazed along at 14.4 kbps
while typing up your telephone line, and a nice lady's voice announced "You've Got
Mail" when a new message arrived...
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and text used on the RF Cafe website are hereby acknowledged.
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FireWire of a Different Sort
FireWire of a Different Sort
Two items in the news headlines
recently brought to mind yet another memorable (funny) incident in my many-faceted
electronics career. The first item is a survey of the number of homeless people
being reported in the latest accounting of Chicago downtown streets – an astoundingly
low number of just 24. According to skeptics, this number purportedly was designed
to help make the city look attractive as a location for the 2016 Summer Olympics.
The second news item is the recent rash of thefts of copper off construction sites
countrywide – both plumbing pipes/fittings and electrical wire. Copper has skyrocketed
in price in the last couple years, as anyone who has lately bought Romex wire for
a home project can attest to.
Back in the early 1990s, I worked as the lead
re-design engineer on a van-mounted remote utility meter interrogation unit that
was used to collect consumption data for electric, gas, and water meters. According
to the company's literature, the transceiver was capable of achieving something
like 99.5% read rate on all installed meters while traveling at up to 45 miles per
hour. The system's meters worked in the unlicensed 900 MHz ISM (Industrial, Scientific,
and Medical) frequency band, and so did the interrogation unit. Meters had to be
situated within 1,000 feet of the roadway, and not be enclosed in a metal framework.
The system was first deployed in the 1980s while there were relatively few users
of the 900 MHz band. By the time I arrived on the scene, the 900 MHz noise floor
had been raised significantly due to wireless baby monitors, wireless security camera
systems, wireless SCADA (Supervisory Control And Data Acquisition) systems, to name
a few. Consequently, the remote meter reading equipment performance had degraded
significantly, to the point where many of the utility companies were reporting read
rates of 90% or worse, even with the van traveling at very low speeds. They were
Because our company's remote meter reading equipment was expensive
to install - all existing meters needed to be replaced with ERT-based (Encoder-Receiver-Transmitter)
models – the main customers were large urban utilities. Part of the motivation for
deployment of these remote reading systems was to eliminate the need to send human
meter readers on foot into some of the dicier sections of the city. It was (is)
not uncommon for the utility companies to have to hire armed, off-duty policemen
go into some areas to read the meters because the crime rate is so great. They told
us stories of finding meters with bullet holes in them. Some meter readers had been
shot at while attempting to get into a meter room or into an alley to access meters,
having happened upon a drug deal going down or maybe a mugging.
a few months of studying the problem, testing the existing equipment, designing
retrofits, and testing new equipment, we scheduled a field test in one of the roughest
environments available – Chicago. I was not exactly thrilled at the thought of being
a White-boy, riding with another White-boy, in a minivan with curtains on the windows
and a ¼-wave whip antenna on the top, through the streets of some of the most notoriously
crime-ridden sections of Chicago. Try as I did to convince the higher powers that
perhaps our own rural location in southern Minnesota might serve the same purpose,
my persuasion powers had no sway with them. Besides, we had to pacify our big $$$
customers. So, off we went for a four-day extravaganza in the Windy City.
Let me digress to comment on the impressive level of ingenuity and engineering
that went into the original system. It was designed mostly by former employees of
Johnson Radio (the mobile and Citizens Band radio people), who really knew their
stuff. The entire product was born out of an alliance between this new company,
a handful of utility companies, and the University of Minnesota – at least that
is my recollection. The ERTs were a marvel in and of themselves, using a custom
ASIC (not so common in the late 1980s), a current-sipping superregenerative receiver
and a transmitter sharing a single transistor, and a 12-year lithium battery. A
frequency-hopping spread spectrum scheme was used in the van-based unit to collect
data from the meter units. It was truly ahead of its time.
We arrived at
the ComEd (Commonwealth Edison, part of Exelon) offices early one September morning
and met with their project manager, who briefed us on the areas we would use for
our tests. The HQ building was located near Grant Park. Reports were provided of
problem regions where read rates were the lowest. They were some of the worst areas
in the city and, unfortunately, our chosen targets. One of the ComEd engineers rode
with us for the first couple passes, and then we were on our own. It might be my
imagination, but he sure seemed glad to get out of the van and wave goodbye.
We spent the next couple days driving west of there, around the Roosevelt Street
region, within about a 10 mile radius. I do not recall the specific areas, but in
a plot of places we were glad to heed the ComEd engineer's advice of not even stopping
for red lights or stop signs. We drove past chop shops, strings of blocks where
all the store windows had heavy iron bars over them, red light districts, congregations
of employment-challenged people, and many other sights not normally seen by most
people. We received some very threatening stares, and even had times when groups
of people would start moving toward our van (of course we scrammed immediately).
To make matters worse, we needed to make multiple passes through each planned route
in order to get enough data for a statistical analysis. Other than the time I made
a wrong turn while driving through Philadelphia do I recall witnessing urban blight
close-up. I suppose I have lived a sheltered life, in retrospect.
side note: One of the most secure and clean areas we traveled was a Section 8 housing
project where signs were clearly posted that the residents had a zero tolerance
policy for criminals, and they constantly had people patrolling the streets. It
was proof positive that living below the poverty line is no excuse for criminality.
I cannot recall the name of the project.
One of the routes we ran happened
to include a metal recycling facility. They took in aluminum, steel, copper, iron,
etc. We would sometimes stop there to get a drink from the vending machine. All
over the parking lot would be guys with copper and aluminum electric cable stripping
off the insulation – it had to be removed before any payment would be made for it.
They would tie one end to a fence pole and stretch it out, then take a pocket knife
and strip off the insulation. It was a lot of work to get all that insulation off,
and it took quite a while to get enough copper to buy a six-pack or a fifth. They
came in a continual train off the street with their shopping cart filled with copper
wire and pipe. It did not take a genius to figure out that those guys did not get
the material through legitimate channels.
Now here is the good part. One
day we were sitting there in the green zone, drinking our Cokes, when we noticed
a billowing cloud of black smoke coming from the other side of the overpass just
past the recycle station. It seemed to be getting slowly closer. Curious, we fired
up the van and headed off toward the smoke.
As we crested the overpass, we
just could not believe what we saw – some guy had figured out a way to avoid all
that tedious insulation stripping by burning it off in the shopping cart while walking
toward the recycle station. I kid you not. He struggled to keep upwind of the significant
amount of smoke, never seeming to care about the attention he had brought to himself.
We turned around to follow him to confirm our suspicion of his ultimate destination.
At least one police car just drove right on by him, never bothering to challenge
his business practices.
So the question is, should the guy be condemned for
polluting the atmosphere, or celebrated as an early adopter of the recycling movement?