Hi, I understand that you have done some trials with Audiomoth and LoRa in Belize (based on your post in April 2019). May I know if there are any updates? We would like to use the Audiomoth for sensing gunshots, and real-time alerting of rangers via a LoRa network. Thanks a lot!
Question
1) Does the AM have a resonance, or excess gain at 20kHz? I tried a dozen indoor/outdoor settings, and there is always a band at 20kHz. The spectrum below is inside a quiet room. 2) In most of the indoor, quiet room, recordings, I see a rising thin line in the 30-50kHz range, see the above spectrum, the five panels cover about 20 minutes. Could this be a form of self-noise? 3) The clicking noise, I saw on other posts that this is SD card writing? I only see this occasionally. The image below was from inside a parked car at night - very quiet. Is the suggestion still to get the "Extreme" version of the SD card? Thanks - I love the unit. Keep up the good work - you are making a lot of research possible.
The range in tropical forests was very limited - down to 200m sometimes which was quite disappointing. Suspect that it depends on the terrain, and the density and type of vegetarian so needs more experimentation. If you can get clear line of sight back to the ranger station it would probably work well.
Thanks Alex. I have tried LoRa transmissions on campus, and was also unable to attain reliable communications beyond 500m. May I find out from you, based on your experience in Belize, how long each Audiomoth will last when powered by the 3 AAA batteries?
The configuration app gives the energy consumption depending on the configuration used. For long duration deployments we use Energizer Lithium Ultimate batteries but standard Alkaline batteries are pretty good as well. For the long term deployments in Belize we used large 6V lantern batteries, which with custom firmware running the gunshot detection algorithm, meant we could listen (not record) for 12 hours each day, for one year.