I’m helping a client that runs a small town’s water network with a meter-reading pilot, about 1,500 meters, in Europe. One radio vendor is pushing a TV white space system (Weightless-style, long range, says it goes through anything). Two questions:
- How do you even work out which white space frequencies you can use? The vendor was vague.
- The client saw Hermetry City in a brochure and wants the meters in there. Does City handle meter networks, or do we go through the normal device side?
I’m a data person, the radio side is not my strength.
As far as I know you don’t pick white space channels yourself. The radio asks a geolocation database approved by the regulator, which tells it what’s free at that spot and at what power.
Aisha’s right. And the catch is the ecosystem: very few meters speak it, so you’d be tied to that one vendor for the meters too. LoRaWAN meters are on the shelf from a dozen makers.
That’s roughly what our procurement person said. The vendor’s meter list was three models long.
I work in water and wastewater and we went through the same thing two years ago.
On City: there’s no doc page for it, so I can’t tell you what it adds for meters. What I can tell you is how the meters themselves go in, which is the regular IoT side with Hermetry’s own LoRaWAN network server. The frequency plan follows your gateway, so EU868 gear in Europe, with OTAA or ABP and Class A or C. There’s a codec library (106 codecs last time I looked) so many meters decode without you writing anything, and pairing mode helps when you’re adding hundreds of the same model.
Things we set up for meters:
- Unconfirmed uplinks. Every ack costs gateway duty cycle, and on 1 % sub-bands that runs out fast.
- The meter’s volume as a counter. On charts and the history API the increase aggregate gives you consumption per hour or day, including when a meter rolls over.
- A Device offline rule so silent meters show up, set longer than the reporting interval.
If the client ever insists on the white space radio, its own gateway would have to report the meters as child devices over MQTT on the v1/gw topics. Possible, but you’d be writing that gateway software yourselves.
The codec list is here: The codec library
How many gateways did you need for a district that size?
Thanks Megan, this settled it. The proposal now says LoRaWAN EU868 meters from two makers whose codecs are already in the library. City the client can ask about separately, the meters don’t depend on it. We booked a coverage survey for three gateway spots.
tsmith, for us it’ll depend on the survey, I’ll post the numbers when we have them.
For the survey: carry one test sensor around and watch the frames log. RSSI and SNR per frame told me more than any coverage map.
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