Antenna trial and error

[uiaunder]

Love rtlamr - using it for a water meter and a gas meter. Fingers crossed that the utilities don't encrypt any time soon. The meters both push a consumption message every 30 seconds. I invoke rtlamr every 5 minutes and set a 2.5 minute timeout.

The gas meter is maybe 40 yards and behind another structure from where I'm trying to read it. I tested a bunch of antennas and my hit rate on getting a reading was about 50% on most, but with this one simple antenna, setting flat against the wall, I am getting 100% success - so highly recommend trying this little antenna for anyone with antenna struggles: https://www.amazon.com/dp/B0CZ8CBQ1T

My water meter is in a pit roadside, probably 60 yards away. Couldn't read it unless I was outside and almost on top of it. I buried a coax from the house to the pit and stuck the little antenna above in the pit. I "sealed" it in tape to try and protect it. That setup gets me a reading rate of 100%.

I'm using a Raspberry Pi 4B to run RTLAMR. I experimented with an Orange Pi zero 3, and a Raspi Pi zero W, but found they both would miss picking up a reading about half the time. I'll guess it has to do with the Pi zero having a lower effective sampling rate.

[uiaunder]

oh, found a thingaverse for the diy crowd:

https://www.thingiverse.com/thing:4566088

[bemasher]

Just curious: why run rtlamr every 5 minutes with a 2.5 minute timeout? Why not leave it running?

[uiaunder]

I'm remote from the location and needed it to be unattended. My simple idea for reliability was to kick off a script every 5 minutes, make sure rtl_tcp/rtlamr are not running, fire them up to try a reading, then close them down. I guess I thought that was more reliable at working for months on end than leaving them running.

[bemasher]

It's probably more reliable to leave it running, and use a service manager such as systemd to restart it when it fails. rtlamr is designed to exit when it encounters an unrecoverable error, like lost connection to rtl_tcp.

[uiaunder]

yeah, I thought about monitoring and restarting, but that seemed like more work :-)

the water meter monitoring has been running for going on 3 years this way without issues so I'm not inclined to mess with it

well, it did fail once a year ago when the battery in the meter died (10 years old), and the water co replaced my meter - I had to update my script to look for a different meter