[NLRS] RF read water meters

Sat Jul 21 12:52:49 EDT 2012

Sofar I've detected nothing. The display hasn't changed from 
transmitting on HF, 6m 2m or 432 though the roof mounted antennas are 
not far from its usual resting spot. I laid the 10:1 probe of my Tek 475 
against the display case and triggered the read request several times. 
Nothing detected and that's flat to 200, 5 dB down at 400 and quits 
about 450 MHz. I fired up the counter stack (HP 5338B provides a super 
reference for the EIP. Neither counter admitted by showing its input was 
triggered of detecting any signal. HP 100 or 200 MHz (doesn't have the 
1500 MHz optional input), EIP that counts to 18 GHz admitted nothing and 
I know its working because I used it to set my sweeper to 10368 for 
matching a feed horn and coupled horn to horn. I use a bit of thin 
solder for the counter antennas. It will take a lot more tries to find 
it with continuously tunable receiver even at wide FM bandwidth. Maybe 
if I run out of projects some year, I'll find out.

The installation and programming manual for the installer, 
ORION_IOM_Water-Meter-Monitor_ORI-IOM-41.pdf does require it to be 
programmed to the meter serial number 7 digits. It says its part 15 and 
must accept interference and not produce any harmful unterference. With 
some meters it can be set to update the reading automatically every 4 
seconds, though with some the monitor gets new data every 4 seconds but 
only updates the visual display hourly. Neither the monitor nor the 
manual admits an FCC registration number from which we could find more 
about the frequency from FCC files.

73, Jerry, K0CQ

On 7/21/2012 9:34 AM, Jim Klassen wrote:
>
>
> Thanks everyone for the responses.
>
> It sounds like there is nothing to worry about w.r.t. the new meter.
>
> 73,
> Jim Klassen (KB0UAZ)
>
> On Jul 20, 2012, at 2:42 PM, Dr. Gerald N. Johnson wrote:
>
>>
>>
>> Mine is an Orion made by Badger Meter Company. The battery operated
>> readout only updates when I push the read button.
>>
>> Many water meters have some sort of rotating wheel or chamber that could
>> spin a little generator through some gears to charge a nicad or nimh or
>> lihium ion battery or super capacitor to accumulate power for
>> responding. Just causes some pressure drop and on this rural water
>> system, there's a pressure regulator on the main side of each customer
>> meter because its miles to the nearest water tower and there are hills
>> and valleys, causing the line pressure to vary and to be as high as 200
>> psi which domestic plumbing can't stand. My pressure runs about 55 psi
>> by my indoor gauge that I use to check for leaks by shutting off the
>> main and watching for any pressure drop. And if I detect a low pressure
>> while the main is on and nothing is using water here, I call the water
>> company to report a leak. So far they've already known about it but
>> thanked me for the call.
>>
>> The previous readout was on the post with an LCD. Water service came to
>> this house in 2004 and that readout was beyond reading with very low
>> contrast a couple years ago so it lasted only about 6 years. The meter
>> from the same water company at my farm put in about 1994 uses a veeder
>> root type display. It never moved, though I used considerable water
>> spraying crops some years, one day they checked, and compared the remote
>> readout to the meter, replaced the remote readout and sent me a bill for
>> 2000 gallons of water. Since then I've rented out the farm and the
>> tenant can't get to the hydrant and has a cheaper source of water for
>> spraying and while the remote probably has broken again, the dials on
>> the meter itself haven't moved either because I've probably used ten
>> gallons a year since then occasionally washing my hands when working on
>> equipment there.
>>
>> I could get the remote readout on this Orion system next to a wide range
>> scope and counter and see what its putting out. Might not last long
>> enough for the counter. If its under 450 MHz, I'll be able to see it
>> with my scope.
>>
>> As for data and modulation format, there are many that can do the job,
>> the amount of data is small, probably includes a meter number as well as
>> the reading and at least a meter number in the query from the remote so
>> as to be usable in crowded urban applications with a dozen or gross of
>> meters per 200 feet of street. I suppose it could even be encrypted with
>> forward error correction and still use up less than 64 bits per
>> transmission.
>>
>> 73, Jerry, K0CQ
>>
>> On 7/20/2012 1:43 PM, Doug Reed wrote:
>>>
>>>
>>> They replaced my meter last month in Maplewood. I haven't bothered to
>>> try and find what frequency it operates on. The meter they installed
>>> here works from scavenged power, most likely from the water flow winding
>>> a spring until it trips to drive a magnet and generate a voltage spike
>>> in a coil. At least that is the way I'd probably build it. I don't
>>> really like the spring option because it might break, but how many
>>> mechanical watches ever broke a main spring?.... Whatever it is has to
>>> be designed for more than 20(?) year MTBF or the water company isn't
>>> going to want it.
>>>
>>> I'd tend to go for a simple burst transmission with an ID code and a 16
>>> or 24-bit pulse count for the water usage. The TX would be random based
>>> on water usage and if any packet was missed, the next would have the
>>> most current data.
>>>
>>> ITI/GES used to build battery powered alarm sensors using AM pulse
>>> position burst transmissions at 320MHz, about 10-20mw RF output. The
>>> cheap receivers were designed to hear a minimum 2mw transmitter at
>>> 500-600 feet LOS. The best receivers we sold would hear the TX at
>>> 2100-2500 feet, or about 1/2 mile. This technology was 20 years old and
>>> would have been easy to integrate into a water meter. These days the new
>>> products are using ASIC chips with the RF and other electronics
>>> integrated on a single chip. Lower parts count should improve
>>> reliability.... I would choose to use 434MHz or another low-power band
>>> rather than 915MHz if I could help it.
>>>
>>> I wouldn't expect the meter to have an active RX-TX system as I've heard
>>> suggested because that would require a more reliable power source that
>>> I've described. But if your water meter mounts outside, it might have
>>> solar cells. If it has an AC power connection indoors, then it might
>>> have a RX-TX polling or mesh system. On the other hand, maybe the water
>>> wheel generator has more power capability than I'd expect. It should
>>> certainly be capable of more "work." Of course this is all pure
>>> speculation on my part, although I was involved in a similar
>>> demonstration project 20 years ago....
>>>
>>> 73, Doug Reed, N0NAS.
>>>
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>
> James Klassen
> Graduate Student
> University of Minnesota
> Natural Resources Science and Management
> 210 Green Hall
> 1530 Cleveland Avenue N.
> St. Paul, MN, 55108
> Email: klas0037 at umn.edu
>
>
>
>
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