Local Radio overlap with Accelerometer Measurements
Local Radio overlap with Accelerometer Measurements
(OP)
Hello there,
I work as a graduate engineer at an acoustic engineering firm here in Sydney. This is week 10 into the job and I'm loving it!
Last week I noticed something very strange while analyzing data from one of our ground-borne noise measurements at a residential property.
We had 3 PCB accelerometers (one per axis) setup in the property's backyard and 3 inside the property. While going through the recordings at the office, I was VERY surprised to hear that the accelerometer had recorded a local (maybe?) radio broadcast! So while I could hear the roadheader I was supposed to be hearing, I was also clearly able to hear the music from a local channel playing South Indian music. Now neither me, nor my colleague, heard anything while on site. Moreover, the accelerometers inside picked up nothing, and neither did the SLM we had setup.
While everyone at the office had a good laugh at this, we couldn't explain why this had happened. Loud music playing far away? Recording was way too clear for that. Signal crossover from an unauthorized radio broadcast? Maybe but how?
Have any one of you ever come across this?
I work as a graduate engineer at an acoustic engineering firm here in Sydney. This is week 10 into the job and I'm loving it!
Last week I noticed something very strange while analyzing data from one of our ground-borne noise measurements at a residential property.
We had 3 PCB accelerometers (one per axis) setup in the property's backyard and 3 inside the property. While going through the recordings at the office, I was VERY surprised to hear that the accelerometer had recorded a local (maybe?) radio broadcast! So while I could hear the roadheader I was supposed to be hearing, I was also clearly able to hear the music from a local channel playing South Indian music. Now neither me, nor my colleague, heard anything while on site. Moreover, the accelerometers inside picked up nothing, and neither did the SLM we had setup.
While everyone at the office had a good laugh at this, we couldn't explain why this had happened. Loud music playing far away? Recording was way too clear for that. Signal crossover from an unauthorized radio broadcast? Maybe but how?
Have any one of you ever come across this?





RE: Local Radio overlap with Accelerometer Measurements
Walt
RE: Local Radio overlap with Accelerometer Measurements
I didn't pick up anything on my SLM or internal accelerometers. Also, the radio signal on the external accelerometer wasn't from a pass by, it was a long event that encompassed almost the length of the recording.
RE: Local Radio overlap with Accelerometer Measurements
Cheers
Greg Locock
New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?
RE: Local Radio overlap with Accelerometer Measurements
The cable for the external acc was 30m, compared to 5m for the internal acc.
The acc was PCB Model:352C04 single axial accelerometer.
RE: Local Radio overlap with Accelerometer Measurements
What signal conditioner and accelerometer cables are you using?
Best regards,
Jason
RE: Local Radio overlap with Accelerometer Measurements
Ted
RE: Local Radio overlap with Accelerometer Measurements
Cheers
Greg Locock
New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?
RE: Local Radio overlap with Accelerometer Measurements
Walt
RE: Local Radio overlap with Accelerometer Measurements
How is the gain used in context of the accelerometer?
What do you guys mean by an A/D system?
RE: Local Radio overlap with Accelerometer Measurements
Cheers
Greg Locock
New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?
RE: Local Radio overlap with Accelerometer Measurements
Steve