Hi Folks,   The mystery NOISE is solved!   Thanks to your suggestions, I =

removed the magnet assm. from the coil, of the sensor, and the noise=20
stopped.  It started again when I replaced the magnet. RFI noise was=20
therefore unlikely.

 The spikes looked similar to when I approached the sensor and stood =
next to=20
it, as it sensed my weigh on the concrete floor.  During the night time=20
hours the noise was gone.  It first I thought of road construction but =
it=20
continue even on Sat and Sun.so I looked for other possibilities.

  On Thanksgiving, on our way to the in-laws, we had a road detour.  I =
gave=20
it no thought as I had turkey and pie on my mind.
I drove back to the detour work area this morning before 8:37am to see =
if=20
they had heavy equipment, like a bulldozer.
I found a large backhoe used to remove old roadway, and someone already =
at=20
the controls, but it was not running.  I spoke to the guys, explained my =

interest, and ask about their work schedule.  They said they did not =
work on=20
Sat and Sun.  but pointed down the road to another crew and other =
equipment,=20
saying they might work weekends.  I thanked them and ask permission to =
walk=20
down to the other crew.
There I found a huge pile-driver, inactive.  I talked to the crew and =
asked=20
their schedule, it matched my noise.  One of the guys volunteered to =
call me=20
at home when they were ready to drive the next pile.  The pile were iron =

I-beams maybe 10" square x 24' long.  The site is only 1.5 miles =
Northwest from=20
my sensor.  The sensor is pointing North/South and is a Lehman Horz.=20
Pendulum.  When I got home I waited for the call, but could  already see =

some noise about 1/2 the size and shorter time durations, then my =
earlier big spikes.  Very similar to=20
what you would expect by digging up the road with a backhoe, but no 5 to =
30mins patterns. No call at this time, but=20
I figured the backhoe was now operating.

Later, I got the call, from the second crew, they were ready to start=20
the pile-driver, as they did, the sensor started picking up the same =
mystery=20
noises.   I know this was a "DA!" moment.  If I would place my ear to =
the ground I=20
might hear something that huge. =20

I am going to print the signals and enlarge them, one each for the road=20
crew.  The trace, to me is interesting, and I now can pick out which is =
the=20
backhoe and which is the pile-driver.

It was suggested to post a picture of this noise, on Larry's site and a=20
picture of the sensor.  If I can do this I will try to include a =
location=20
map and a picture of the heavy equipment.

Many thanks to all of you for your help.  Ted







Hi=20
Folks,   The mystery NOISE is solved!   Thanks to =
your=20
suggestions, I 
removed the magnet assm. from the coil, of the =
sensor, and=20
the noise 
stopped.  It started again when I replaced the =
magnet. RFI=20
noise was 
therefore unlikely.

 The spikes looked similar =
to when=20
I approached the sensor and stood next to 
it, as it sensed my weigh =
on the=20
concrete floor.  During the night time 
hours the noise was =
gone. =20
It first I thought of road construction but it 
continue even on Sat =
and=20
Sun.so I looked for other possibilities.

  On Thanksgiving, =
on our=20
way to the in-laws, we had a road detour.  I gave 
it no thought =
as I=20
had turkey and pie on my mind.
I drove back to the detour work area =
this=20
morning before 8:37am to see if 
they had heavy equipment, like a=20
bulldozer.
I found a large backhoe used to remove old roadway, and =
someone=20
already at 
the controls, but it was not running.  I spoke to =
the guys,=20
explained my 
interest, and ask about their work schedule.  They =
said=20
they did not work on 
Sat and Sun.  but pointed down the road to =
another=20
crew and other equipment, 
saying they might work weekends.  I =
thanked=20
them and ask permission to walk 
down to the other crew.
There I =
found a=20
huge pile-driver, inactive.  I talked to the crew and asked =

their=20
schedule, it matched my noise.  One of the guys volunteered to call =
me=20

at home when they were ready to drive the next pile.  The pile =
were=20
iron 
I-beams maybe 10" square x 24' long.  The site is only 1.5 =
miles=20
Northwest from 
my sensor.  The sensor is pointing =
North/South and=20
is a Lehman Horz. 
Pendulum.  When I got home I waited for the =
call, but=20
could  already see 
some noise about 1/2 the size and shorter =
time=20
durations, then my earlier big spikes.  Very similar to =

what you=20
would expect by digging up the road with a backhoe, but no 5 to 30mins =
patterns.=20
No call at this time, but 
I figured the backhoe was now=20
operating.

Later, I got the call, from the second crew, they were =
ready=20
to start 
the pile-driver, as they did, the sensor started picking up =
the=20
same mystery 
noises.   I know this was a "DA!" =
moment.  If I=20
would place my ear to the ground I 
might hear something that =
huge. =20


I am going to print the signals and enlarge them, one each for =
the road=20

crew.  The trace, to me is interesting, and I now can pick out =
which is=20
the 
backhoe and which is the pile-driver.

It was suggested to =
post a=20
picture of this noise, on Larry's site and a 
picture of the =
sensor.  If=20
I can do this I will try to include a location 
map and a picture of =
the=20
heavy equipment.

Many thanks to all of you for your help. =20
Ted