NOAA Weather Radio "beeps"

Dec 16, 2003
Seattle, WA
Hey folks.

I am curious about an occasional medium-frequency, low-volume beep, or double-beep that is heard over NOAA Weather Radio. The beeps repeat every few seconds. They are audible under the voice.

I most recently heard it on the Lubbock NWR, but several minutes later it stopped. I've noticed it from time to time for years.

It's an indication that the transmitter is on low power. One beep for the primary transmitter, two beeps for the secondary transmitter. Main-line transmitters are configured for 1000 watts, and any number of circumstances can trigger low power. Not sure of the exact wattage when on low power, but coverage is greatly reduced.
I asked a tech at MKX about this years ago, and he said the 1,000 watt primary site drops to something like 10 watts when running on batteries (if the generator fails) or if the power amplifier trips (when the tower is hit by lightning).