What is that noise?

Looking at the trace from the 5.7 'quake NW of the Kuril Islands, I wondered what that noise band was at ~30Hz

30Hz and constant is usually something electrical (60Hz in the US). So traced it back to see when it began

Hmmm 04:00 … my lawn sprinklers are set to start at 4am.

This shows relative locations

The star is the ‘shake. The lawn is 165’ away, and the well head is about 60’, but the pump itself is then about 300’ down. I initially thought it was probably the sprinklers that it was picking up … but 30Hz … it almost certainly has to be the pump.

Finding a quiet spot for a 'shake anywhere around human habitation is harder than you think.


Very curious Philip, but also very interesting! Never seen the noise from a sprinkler’s system pump before.

And yes, especially if you have limited space, you need to do a fun “treasure hunt” for the quietest spot in your house, which can be fun and rewarding!

1 Like

The well provides all the water. For the house as well as the lawn. I never noticed that before, probably for two reasons:

  1. I never looked for it.
  2. Normally, the pump will be running very intermittently, providing much less water.

The location in the barn was the quietest I could find. Nowhere in the house was quiet enough, especially when the AC/Heat Pump was running. I might be able to do better if I wanted to construct something to house it and run power out to it.

BTW, I also checked the “other end” of that signal - it cut off cleanly 2 hours later, when the watering cycle completed.


Finding a quiet spot free of cultural noise is hard. I initially set my RS&B up in the house, and found I had all the usual noise, like washing machine, doors, etc so I thought I’d move it out the the observatory which is about 15m from the house. I set it up there and it ran briefly before comms failed and I had to reburn the SD card to get the shake working again, but it was long enough to work out that the observatory was very little different from inside the house - it still got the washing machine, and some door closures in the house, etc and of course it made no difference to the log trucks passing along the road out the front (about 100m away).

So in the house was easiest, where I can connect directly to ethernet.



My 'shake is ~22m from my office. The barn is metal, but has a window and wooden door on the side, not directly facing the house.

I use a coupe of these:

To extend my network into the barn. The barn end is mounted internally. I wondered if I would get away with that, but it works fine, both are running about half power.
I have a UPS for the WiFi radio and 'shake. It has been pretty reliable. The only interruption was a power outage that lasted about 5 hours. I have generator power for the home network, but not in the barn, so after about 2 hours the UPS shut down.

It is an acceptable compromise (for me). I might be able to do better, but I could spend a lot of time and money only to find other issues arising.