Usually there is not much action on our side. Now the interesting
part, we both heard this strange noise. I have been to the GLR warning
signs at least 40-45 times and never heard anything like this before.
It sounded like a rumble just past the first set of hills. I thought
it sounded like a hot air balloon when they pull the cord to fill it.
It sounded like engine thrusting but there was nothing in the sky. It
would last 12-15 seconds at a burst and then stop suddenly. This
happened at least 3-4 times. Is it possible to hear engine thrust
testing from Groom at the GLR warning signs. To me it seems way too
far. I was able to capture this sound twice on my digital camera. The
video quality sucks! The loudest sound is my camera. If you
concentrate on the background sound you will hear the rumble. It was
quite noticeable at the GLR. Everybody heard it and questioned what it
was. If you watch the video a few times you can hear the sound.