All Song Meter models predict when the sun will rise and set based on the internal clock, latitude and longitude, and the time zone. The internal clock and latitude/longitude values can be set manually or by attaching a Wildlife Acoustics GPS accessory for long enough for the Song Meter to sync these values to a GPS signal. Note that because time zones are determined by national and state/provincial boundaries as well as local conventions regarding Daylight Savings Time, the recorder's time zone must always be set manually.
If you notice that your Song Meter is incorrectly predicting the times of sunset and sunrise, here are some settings you should double-check:
- Make sure that the date and time settings are accurate to local time.
- Check that the recorder's latitude and longitude settings are approximately accurate for the recorder's location. Note that Song Meters do not use negative latitude or longitude values to denote the Southern and Western hemispheres, but instead use N/S and E/W characters. For example, rather than noting the location of São Paulo, Brazil as (-23.6,-46.6), you would enter it as (23.6 S, 46.6 W).
- Confirm that your UTC offset is set accurately for your timezone. With a few exceptions near the prime meridian and antimeridian, regions in the Eastern hemisphere have positive UTC offsets, and regions in the Western hemisphere have negative UTC offsets. Note that if your region observes Daylight Savings Time, there will be two different UTC offsets depending on time of year (see note on DST below).
Daylight Savings Time
When a region is observing daylight savings time, the UTC offset for the region is increased by (usually) 1 hour, and the clock is adjusted to match the new offset. For example, US Eastern Standard Time is UTC -5:00, and US Eastern Daylight Time is UTC -4:00. If DST starts or ends in the middle of your deployment, your Song Meter will not automatically adjust its UTC offset or clock, since it has no way to know if or when your region observes DST.
If your Song Meter is scheduled to start recording at sunrise, it will continue to do so accurately, but all time stamps will be relative to the UTC offset programmed into the recorder. For example, if sunrise is supposed to be at 07:30 US Eastern Daylight Time (UTC -4:00), but the recorder is still on US Eastern Standard Time (UTC -5:00), then it will wake up at 06:30 according to its internal clock. Even though the timestamp is off by an hour, the recorder is still waking up when the sun rises.