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<font face="Arial">David, et al, the values from Dave Witten's
software are in microteslas so 46.9 to 47.1 uT is a 200nT jump,
quite large in comparison to what may be no more than +/- 20nT
diurnal variation in the absence of signficant geomagnetic
activity. <br>
<br>
I believe you need to interchange your Z and X values (as read
from the software which assumes the RM3100 PC board is horizontal
with connector pins pointing down and the white arrow in the left
corner of the board indicating the magnetic North direction.<br>
<br>
But, even considering the large magnitude of those signals, they
are pretty clearly man made and could relatively easily be removed
from the data stream.<br>
<br>
Regards,<br>
Jules<br>
<br>
</font><br>
<div class="moz-cite-prefix">On 6/30/2021 5:59 PM, David Waugh
wrote:<br>
</div>
<blockquote type="cite"
cite="mid:9A246DC1-D5B3-4A13-81FC-18AFD7E62444@kent.edu">
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<div class="">N5PA was interested in the what the lawnmower would
do, and I had a chance to look at that. The image below (I’m not
positive the list can take attachments) is a crude and not
proofread illustration of the data. My mower is just a steal
deck battery powered self-propelled mower that looks like a
normal gas push mower. The times indicated by the vertical red
lines were inserted into the timeline based on timestamps of
photos from my cell phone, so for the two “big” events there is
a lag between me fumbling with the phone and getting the photo.
Below the first panel of graphs is all the data I have for that
day to provide some context. So it’s clear that when the mower
was really close to the magnetometer (and stationary), it
produced a large signal, but when examined in context of the day
it was just a very minor spike that I’m guessing could be easily
ignored. By the time I was working on the central part of the
yard, the signal hardly shows up. </div>
<div class=""><br class="">
</div>
<div class="">I’ve got more data on parked cars which seem to have
a larger, or at least more persistent signal, although in an
initial test a car about 70 feet away produced very little, if
any signal, I would like to narrow down what that distance
really is. Cars within ~32 feet still create a signal, although
I don’t know to what extent that would degrade the usefulness of
the data (that would be an interesting conversation to have with
those using the data). -David KE8QEP</div>
<div class=""><br class="">
</div>
<div class=""><img apple-inline="yes"
id="6D4A2F40-292B-432C-8A44-58D75CC19558"
src="cid:part1.AA6AD940.8B1C6D5E@fairpoint.net" class=""><br
class="">
<div class="">
<div class="">David A. Waugh, Ph.D.<br class="">
Research Assistant<br class="">
Department of Anatomy and Neurobiology<br class="">
NEOMED<br class="">
4209 State Route 44<br class="">
Rootstown, OH 44272</div>
</div>
<div><br class="">
<blockquote type="cite" class="">
<div class="">On Jun 28, 2021, at 8:33 PM, n5pa <<a
href="mailto:n5pa.dx.341@gmail.com" class=""
moz-do-not-send="true">n5pa.dx.341@gmail.com</a>>
wrote:</div>
<br class="Apple-interchange-newline">
<div class="">
<meta http-equiv="content-type" content="text/html;
charset=UTF-8" class="">
<div dir="auto" class="">Tnx for the info David!<br
class="">
<br class="">
<div dir="ltr" class=""><span style="background-color:
rgba(255, 255, 255, 0);" class=""><i class=""><b
class="">73,</b></i><br class="">
<i style="font-weight: bold;" class="">Alan Clark,
N5PA<br class="">
</i>Ellisville, MS<br class="">
Email: <a href="mailto:n5pa@n5pa.com"
title="mailto:n5pa@n5pa.com" class=""
moz-do-not-send="true">n5pa@n5pa.com</a><br
class="">
URL: <a href="http://www.n5pa.com/"
title="http://www.n5pa.com/" class=""
moz-do-not-send="true">http://www.n5pa.com</a></span></div>
<div dir="ltr" class=""><br class="">
<blockquote type="cite" class="">On Jun 28, 2021, at
7:22 PM, David Waugh <<a
href="mailto:dwaugh@kent.edu" class=""
moz-do-not-send="true">dwaugh@kent.edu</a>>
wrote:<br class="">
<br class="">
</blockquote>
</div>
<blockquote type="cite" class="">
<div dir="ltr" class="">
<meta http-equiv="Content-Type" content="text/html;
charset=UTF-8" class="">
Alan, I’m new to the project and can’t answer your
question. I think there was some theoretical limit
for the cable length, but I can’t remember the
number. My understanding with is that with a
distributed network of sensors, local noise can be
filtered out (or maybe in some cases corrected), so
your lawn mower (and mine) will show up as a
momentary spike and could either be “smoothed" or
cut from the dataset. I would assume some of this
early data will help the end users (of the data)
figure out what sorts of setups are usable, and come
up with strategies to filter the data as needed.
The more sensors available the more can be done,
even if each sensor location has some occasional
temporal issues. One can never have enough data, and
data is never perfect. -David KE8QEP<br class="">
<div class="">
<div class="">David A. Waugh, Ph.D.<br class="">
Research Assistant<br class="">
Department of Anatomy and Neurobiology<br
class="">
NEOMED<br class="">
4209 State Route 44<br class="">
Rootstown, OH 44272</div>
</div>
<div class=""><br class="">
<blockquote type="cite" class="">
<div class="">On Jun 28, 2021, at 7:16 PM, n5pa
<<a href="mailto:n5pa.dx.341@gmail.com"
class="" moz-do-not-send="true">n5pa.dx.341@gmail.com</a>>
wrote:</div>
<br class="Apple-interchange-newline">
<div class="">
<meta http-equiv="Content-Type"
content="text/html; charset=UTF-8" class="">
<div dir="auto" class="">
David:
<div class=""><br class="">
</div>
<div class="">Good info on the Magnetometer
tests! I wonder what effect my zero turn
mower would have running over it when it
is buried or my heat pump running. What
would be the maximum distance you can run
the cable?<br class="">
<br class="">
<div dir="ltr" class=""><span
style="background-color: rgba(255,
255, 255, 0);" class=""><i class=""><b
class="">73,</b></i><br class="">
<i style="font-weight: bold;" class="">Alan
Clark, N5PA<br class="">
</i>Ellisville, MS<br class="">
Email: <a href="mailto:n5pa@n5pa.com"
title="mailto:n5pa@n5pa.com"
class="" moz-do-not-send="true">n5pa@n5pa.com</a><br
class="">
URL: <a href="http://www.n5pa.com/"
title="http://www.n5pa.com/"
class="" moz-do-not-send="true">http://www.n5pa.com</a></span></div>
<div dir="ltr" class=""><br class="">
<blockquote type="cite" class="">On Jun
28, 2021, at 5:59 PM, David Waugh via
TangerineSDR <<a
href="mailto:tangerinesdr@lists.tapr.org"
class="" moz-do-not-send="true">tangerinesdr@lists.tapr.org</a>>
wrote:<br class="">
<br class="">
</blockquote>
</div>
<blockquote type="cite" class="">
<div dir="ltr" class="">Tangerine list
folks, with the help of Jules for
suppling the boards (and help along
the way), I was able to get the
magnetometer running. Currently the
magnetometer is buried about 2.5 feet
in the ground under my deck. I have
plans to to move it farther away from
the house and driveways if needed.
Attached is a short run (not perfect
graphs) I made this morning with some
notes about moving the cars around
(purposefully to record the
influence). The cars were parked maybe
30 feet from the magnetometer. Clearly
they show up (moving the cars around),
but it seems as if might be easy to
correct, or recognize and ignore the
disruptions. I can do some more tests,
and a better “write up” to try and
come with a distance for which
periodically moved parked cars show up
in the data if people in the group
think that might be useful. I’m
excited about the project and look
forward to collecting more data. I
will post again once I have some
longer runs, but if there is anything
that I can examine, specifically, that
would be helpful, please let me know.
-David -KE8QEP
<div class=""><br class="">
</div>
<div class=""><br class="">
<div class=""><br class="">
</div>
<div class=""><br class="">
</div>
</div>
<div class=""><cars_moving_June_28.pdf></div>
<div class="">
<div class=""><br class="">
<div class="">
<div class="">David A. Waugh,
Ph.D.<br class="">
Research Assistant<br class="">
Department of Anatomy and
Neurobiology<br class="">
NEOMED<br class="">
4209 State Route 44<br
class="">
Rootstown, OH 44272</div>
</div>
<br class="">
</div>
</div>
<span class="">-- </span><br class="">
<span class="">TangerineSDR mailing
list</span><br class="">
<span class=""><a
href="mailto:TangerineSDR@lists.tapr.org"
class="" moz-do-not-send="true">TangerineSDR@lists.tapr.org</a></span><br
class="">
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href="http://lists.tapr.org/mailman/listinfo/tangerinesdr_lists.tapr.org"
class="" moz-do-not-send="true">http://lists.tapr.org/mailman/listinfo/tangerinesdr_lists.tapr.org</a></span><br
class="">
</div>
</blockquote>
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