Digest for sci.electronics.repair@googlegroups.com - 10 updates in 5 topics

captainvideo462009@gmail.com: Jul 07 08:22AM -0700

We received a notice from the power company that they intend to replace our two electric meters with the new wireless units. These meters emit short bursts of RF multiple times a day at a fairly substantial RF level. These transmissions are received by a "collector" which is apparently mounted on a utility pole on the street. This data is sent to a receiver and computer in a power company truck as it drives by and returned to their office where it's downloaded and bills are generated. Great for the power company but not for the meter readers. There are people all over the country up in arms over these things. Some have blocked installations and have been arrested for it.
 
While it's true that many of them are non technical people who just need something to jump up and down about my grand children sleep in the room adjacent to the meters and I think that I understand a little bit more about this, and it concerns me.
 
I asked the power company to provide me with more information and initially I was stonewalled until I contacted my state representative who then contacted them for me. Now they're kissing my ass with information but still telling me this is going to happen at some near point in the future.
 
Has anyone else had to deal with this and can you comment on my safety concerns? If it's true that there is no recourse to them making this modification, to increase the distance squared I've considered moving the meters to a utility pole which is on my property about 75 feet from the house. this would probably have to be at my expense I suspect.
 
The following is some information about these meters. Some of it I had requested and some extra which they threw in. I know that it's a lot to look at but if you can I'd really appreciate if you guys could please have a look at it and tell me what you think. I'm really concerned about this. Thanks very much. Lenny
 
Q. I understand these units operate in RF - Radio Frequency. Are they emitting short or
long range signals?
A: The signal from the meter is transmitted in the range 902-928 MHz (mega-hertz). The
reading capability is dependent on a number of variables and cannot be accurately assessed
without site specific information, but typically the signal may be received by the meter reading
equipment within 1/4 mile or so.
2)
Q: Regarding the signal, is it a "Bubble-Up" unit where it is transmitting all the time or is it
a "Wake-Up" unit where it transmits when it receives a signal?
A: The meter transmits reading data every 30 seconds in a brief milliseconds burst. The
manufacturer designed it that way to accommodate any reading schedule required by the
utility. The meter is a one-way communication device. The meter would not know when the
reading device was going to be in close proximity to the meter, therefore it needs to transmit
frequently so that it may be read whenever the reading device is nearby.
3)
Q: What frequency and wattage of transmit power is the unit operating at and at what
antennae gain?
Ex. Unit transmits at 900MHz with 1 watt of transmit power with antennae gain of 0.
A: The signal from the meter is transmitted in the range 902-928 mhz (mega-hertz) The
maximum power output for the endpoint devices is less than half a watt, while the maximum
power output of the collection device is less than 1 watt. In comparison, the average light bulb is
60 watts.
Frequency = 909 to 922 MHz
Transmit Power = 147 mW (21.67dBm)
Antenna Gain = 0 dB.
4)
Q: What's the antennae gain at peak power and what wattage is the peak power?
Ex. Antennae gain of 4.0 dBi for peak level power of 2.5 watts.
A: The maximum power output for the endpoint devices is less than half a watt, while the
maximum power output of the collection device is less than 1 watt. In comparison, the average
light bulb is 60 watts.
Frequency = 908 to 923.8 MHz
Transmit Power = 250 mW (24dBm)
Antenna Gain = 2.2 dB
5)
Q: How many times in total - both average and maximum - is the unit scheduled to transmit during a 24-hr time frame?
A: The meter transmits reading data every 30 seconds in a brief milliseconds burst - about 53 milliseconds referred to as the "duty cycle". The total RF transmission time in a 24 hour period is between 1.5 - 2.5 minutes depending on the type of meter and therefore data being transmitted. Signal levels are 1/10th of the "Maximum Permissible Exposure Levels" as defined by the FCC--lower than many everyday appliances and electronic devices around your home, and are only transmitted briefly and periodically rather than constantly.
What's the "first hop" technology being used to send?
Ex. Mobile Radio Frequencies? Mesh Radio Frequencies? Fixed Radio?
A: This is not AMI, this is AMR. There isn't any 'first hop', the data is transmitted to a computer in a vehicle driving nearby and then the computer is returned to the utility at the end of the day and directly connected to the utility internal network and the meter readings are uploaded to utility internal systems.
6)
Q: Is this unit considered to be a "Licensed" or "Unlicensed" transmitter by the FCC?
A: The meters operate in the unlicensed 902-928 MHz frequency range and the devices are regulated by the FCC. Itron's products are stringently evaluated for RF safety and meet all Federal Communication Commission (FCC), Industry Canada (IC), and Institute of Electrical and Electronic Engineers (IEEE) standards. FCC OET Bulletin 65 supplement C Edition 01-01 (known as OET-65C) provides further guidance on determining compliance for portable and mobile devices.
7)
Q: Because each unit needs power to run itself, what is the unit's power consumption rate per month?
Ex. 2 kW hours? 1kW hours?
Also, what would be the additional monthly cost of the power the unit needs to function (based on the # of kW hours it needs to function) as I know you guys just had a rate hike?
· A: The power to the meter components is supplied on the line side of the meter. Therefore there is no cost difference associated with the running of the AMR meter to your previous meter. We are enhancing our technology to serve you better. Installing AMR meters allows us to continue to provide safe, timely, accurate meter reading but at a lower cost. Controlling costs is an important factor in determining Eversource rates.
8)
Q: Does the unit have a battery? What is the battery's life (in years)?
A: Yes there is a battery in the unit. The battery's life is the same as the life of the meter which is 20 to 25 years..
For more information pertaining to the AMR C1SR Meter please visit the ITRON website:
https://itron.com/na/resourcesAndSupport/Pages/RF-Resource-Center-FAQs.aspx
https://itron.com/na/resourcesAndSupport/Pages/RF-Resource-Center.
Baron <baron@linuxmaniac.net>: Jul 01 07:47PM +0100

Hi Jon,
 
Jon Elson prodded the keyboard with:
 
> timer. So, it has to be SERIOUSLY old! All the old ones had a
> single motor/pump that was reversed to do both functions. Even our
> much newer one with electronic controls only has one pump/motor
assembly.
 
> Jon
 
Ours is a Philips "Wirlpool" dishwasher, UK made, it has a separate
drain pump. The main motor is a two pole induction one.
 
The only one that I've ever seen with a single motor would have been
30 years old or more, and that had a weird rubber flap valve with a
peg on it that was moved in one direction or the other by the
impellor blades themselves. The valve opened the drain port when
pushed one way and blocked it off when pushed the other.
 
The problem with this arangement was that if debris held the flap away
from the drain port, was that the machine would very slowly empty
itself.
 
--
Best Regards:
Baron.
N_Cook <diverse@tcp.co.uk>: Jul 06 09:36PM +0100

On 06/07/2015 10:46, whit3rd wrote:
> Alternately, if one were to mold the sidewalls as planks with
> an outie-circular edge and innie-circular opposite edge, they'd
> be easy to mortar together at any angle.
 
Standardizing the size of the panels makes sense if destined for either
a 110V or 240V country , as would only be run in parallel , if an odd
number of panels. Kiln cement covers up all sorts of irregularities,
like angled vertical gaps between panels, and refactory bricks can
easily be cut, likewise.
Clifford Heath <no.spam@please.net>: Jul 07 02:05AM +1000

On 06/07/15 23:44, John Robertson wrote:
>> non-symmetry of firing or something?
 
> Well, if you want to get technical, the kiln is actually 8-sided. It has
> a hexagonal box, then a base and a lid.
 
Count again. There are seven vertical sides, a bottom and a top.
N_Cook <diverse@tcp.co.uk>: Jul 07 12:30PM +0100

On 06/07/2015 21:36, N_Cook wrote:
> number of panels. Kiln cement covers up all sorts of irregularities,
> like angled vertical gaps between panels, and refactory bricks can
> easily be cut, likewise.
 
Perhaps with standard voltage and wattage and size panels then a
12-sided kiln having 12 panels would be 3x the power of a 4 panel one,
probably not far off the requirement. Anything else can be cattered to a
great extent, in the on/off programming temperature control
OldeGuye <spamnot@nospam.com>: Jul 06 03:45PM -0700

Just wondering.
Old laptop with all USB2 connectors.
Favorite USB port seems to be wearing out.
I have one USB3 flash drive (Sony) that always connects.
I have several other USB3 flash drives (SanDisk) that either will not
connect or I have to wiggle to get a connection.
I can plug those SanDisk flash drive into other USB2 ports on this same
laptop and they work just fine. These are less often used.
 
What design difference is there such that this would happen?
 
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Jeff Liebermann <jeffl@cruzio.com>: Jul 06 08:56PM -0700

On Mon, 06 Jul 2015 15:45:47 -0700, OldeGuye <spamnot@nospam.com>
wrote:
 
>I can plug those SanDisk flash drive into other USB2 ports on this same
>laptop and they work just fine. These are less often used.
 
>What design difference is there such that this would happen?
 
There are no design differences, but that assumes that the
manufacturers will actually follow the USB connector specifications.
The worst offenders are the USB flash drives, wireless devices, and
mouse dongles that are crammed into a USB connector. It save space
and cost, they use a PCB (printed circuit board) with 4 traces instead
of a proper 4 pin connector. The result is usually a lousy
connection.
 
However, you don't have anything that qualifies, so that's not the
problem. My guess(tm) is that your USB port or plugs are filled with
lint and dirt. Very time I put a flash drive in my pocket, the
connector ends up full of lint. Blow out the loose lint from the
connectors and polish the 4 connections with something made from wood.
I use a toothpick or a wood coffee stirrer. Unless the connector is
obviously mangled and in need of straightening, don't try to "improve"
the connection by smashing the connector so that it will have more
connection force. That never seems to work.
 
If you must use all the ports on your old laptop, you might consider
getting a short USB pigtail cable or adapter, to reduce the wear and
tear on the connector in the laptop.
<https://www.google.com/search?q=usb+right+angle+adapter&tbm=isch>
 
--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
Jeroni Paul <JERONI.PAUL@terra.es>: Jul 06 12:03PM -0700

Jeff Liebermann wrote:
> <http://www.ptb.de/cms/en/ptb/fachabteilungen/abt4/fb-44/ag-442/dissemination-of-legal-time/dcf77/reach-of-dcf77.html>
> Yes, the signal is probably not very strong and you're in the skywave
> only region.
 
Good observer, yes, Spain. Also the Pyrenees are in the way blocking most ground signal.
 
 
> That sounds like the older amplitude modulated system. DCF77 also
> transmits a phase modulated signal,
> <https://en.wikipedia.org/wiki/DCF77#Phase_modulation>
 
I knew about the phase modulated encoding on the signal but I am not sure if any of my clocks use that. The older ones sure do not, time ago I dissassembled the oldest alarm clock and scoped the signal output from its radio board and I could see the 0.1/0.2 sec signal drop.
 
There is a long wave radio transmitter in France at 162 kHz that carries time information by phase modulation of its carrier:
https://en.wikipedia.org/wiki/Allouis_longwave_transmitter
I find it an efficient way to use existing resources, also you can check for reception by listening with a LW radio.

> for an antenna, they are directional, with the strongest signal
> perpendicular to the loopstick. I was having random updates until I
> moved my WWVB clock away from several switching power supplies.
 
Yet, if I had one clock next to a noise source I would expect it to sync less times than the rest. But no, there appears to be a random distribution.
 
 
> It's a bit more than just the parity bit. Some chips require that the
> correct time be received successfully more than once before it will
> sync. This is a function of the chip design.
 
That's what I belived, but then how did it receive incorrect data? Did it actually receive the same wrong data twice in a row? The algorithm could also check for a reasonable deviation against the current setting.
 
> >I think, however, it is somewhat dangerous to have the clocks sync
> >at night *after* you have checked they are set correctly
 
> Sorry, but you don't have a choice as to what time to sync.
 
Maybe a setting to enable sync only during weekends or only when the alarm function is disabled.
Jeroni Paul <JERONI.PAUL@terra.es>: Jul 06 12:08PM -0700

N_Cook wrote:
> Have you had the situation of the displayed time jumping by an hour or two?
> As an alarm clock, losing synch and drifting a second or two , to a
> background quartz crystal clock, is no great problem
 
I think on one occasion it was several hours off. You could tell it was a wrong bit value as the data would be wrong by a multiple of two.
Jeff Liebermann <jeffl@cruzio.com>: Jul 06 04:42PM -0700

On Mon, 6 Jul 2015 12:03:13 -0700 (PDT), Jeroni Paul
>do not, time ago I dissassembled the oldest alarm clock and
>scoped the signal output from its radio board and I could see
>the 0.1/0.2 sec signal drop.
 
I haven't looked into the situation for about a year. I also don't
know the situation in Europe. To the best of my limited knowledge,
there are no commodity clocks and no commodity chips being made that
use phase modulation, in the USA. The technology appears to be owned
by Everset, which has done absolutely nothing for several years. I
could find no distributor that carries their chips. My previous
requests for samples, pricing, and delivery were ignored:
<http://eversetclocks.com>
If you find a consumer grade WWVB chip or receiver that do BPSK, I
would be interested.
 
>There is a long wave radio transmitter in France at 162 kHz that carries time information by phase modulation of its carrier:
>https://en.wikipedia.org/wiki/Allouis_longwave_transmitter
>I find it an efficient way to use existing resources, also you can check for reception by listening with a LW radio.
 
<https://en.wikipedia.org/wiki/TDF_time_signal>
I'm not sure, but might be able to take the demodulated output of a
162 KHz receiver, and feed it to a decoder made for DCF77, and get
accurate time updates. I searched with Google and found nothing in
the way of a consumer grade DCF time clock.
 
You can probably get better info from the Time-Nuts mailing list:
<https://www.febo.com/pipermail/time-nuts/>
 
>Yet, if I had one clock next to a noise source I would expect it to
>sync less times than the rest. But no, there appears to be a random
>distribution.
 
Nope. WWVB sends the time code at the rate of 1 bit/second (1 baud).
One frame is 60 seconds. Hopefully, the European systems are similar.
<http://www.nist.gov/pml/div688/grp40/wwvbtimecode.cfm>
All it takes is one noise hit every 60 seconds, and you'll receive
nothing. If your local noise source is intermittent or random, then
it's more a matter of timing and bad luck that will determine if the
clock decodes anything useful.
 
>> correct time be received successfully more than once before it will
>> sync. This is a function of the chip design.
 
>That's what I belived, but then how did it receive incorrect data?
 
Good question. I don't know. The only time I've seen an incorrect
display was when I was building a WWVB emulator and spraying garbage
data everywhere:
<http://www.instructables.com/id/WWVB-radio-time-signal-generator-for-ATTINY45-or-A/?ALLSTEPS>
However, I've never seen a random erroneous date or time.
 
>Did it actually receive the same wrong data twice in a row?
 
Very unlikely that it might receive the same garbage successfully
twice in a row but possible. However, note that the redundancy
requirement is totally in the chip uses, which might vary in
programming and capabilities.
 
>The algorithm could also check for a reasonable deviation against
>the current setting.
 
I don't think so. Once it gets a valid time to display, it turns off
the receiver to save battery power. No need to decode more than one
or maybe two frames.
 
>Maybe a setting to enable sync only during weekends or only
>when the alarm function is disabled.
 
Personally, I want a graph of signal strength and SNR over a few days
period. Whether anyone is willing to pay for such a feature is
debatable.
 
 
--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
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