Back in the greed filled 1980s, I worked for several years on a project
to build a radio interrogated gas meter. We developed a prototype that
worked at about 404 and 455 MHz. It was designed for ultra low power
consumption, and used the first CMOS microprocessor I had ever seen. I
was mainly involved with the antenna design and testing, but also built
and tested the microstrip RF circuitry. I presume that most of the
modern units are Part 15 devices also, and work in the 900 MHz and 2.4
GHz range. The way our system worked, the meter transponder woke up on
a certain rate, scanned its optical encoder for gas usage, and also
looked for a radio transmission from the mobile interrogator
transmitter. If it were being called by its serial number, it would
respond with a coded sequence containing that serial number and its
latest meter reading. It was a really neat idea. It allowed for much
faster and safer meter readings. No biting dogs, and in really rotten
neighborhoods, you could take readings from aircraft. My city has
switched to a remotely interrogated water meter system. I do not work
above 2 meters, and have never noticed any interference with my station.
My water bills are stable, but rising, reflecting more of the greed of
the local governments, than any interference of the meter system by my rigs.
73,
Steve WA9JML
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