[TangerineSDR] Magnetometer Testing

[David Witten]

Hi Jules,

Yes, I looked at 1.25, 1.5, 2.0 and 3.0 pipe.  The 3.0 stuff is really too
big, but swimming pool noodles (closed cell foam with a hole down the
center fit nicely into it.  But I don't see the advantage of using
something that requires a post hol digger.  I can't do it myself, and my
lot is probably almost all 'clean fill' over weathered limestone. Too much
work.

I found that extruded polyethylene foam insulation (meant for the outside
of 1" pipe) fits very snugly into the 2 inch pipe.  I don't know if that is
needed at all, but it is cheap and available.  I've also been playing with
plugs and shims made from 2 inch polystyrene rigid (pink) foam.  Again,
cheap, workable, and available nearby.

What is your opinion on cascading two mags on two of the new boards with
> different i2c addressing for the two?   My intent here is to get the two
> mags as physically close as possible without interaction to insure
> identical environments for more accurate comparison of the two mags.


Sounds worth a try.  I'm happy to make any mods to the software that are
needed to try this.  It sounds like a good two for (almost) the price of
one.

Thanks,

Dave Witten

On Sun, Nov 1, 2020 at 3:00 PM Julius Madey <hillfox at fairpoint.net> wrote:

> Dave,
> 2 inch PVC is fine .... I chose the 1 1/4 inch because it was a good fit
> for your boards.  2 inch gives you more clearance to work also.  I have the
> same auger set and it works well ... my 1/2 inch cordless drill with
> extended handles for leverage when hitting stones is a big help.
> \
> The earlier email was relative to the pair of mounted mags I had intended
> to send to Hyomin using your original boards.  I could still fab that or
> wait until I get a couple of Scotty's boards or perhaps Gil would like to
> make his own ..... whatever works to get things moving ... I'll wait for
> Hyomin to decided what works best for him.
>
> What is your opinion on cascading two mags on two of the new boards with
> different i2c addressing for the two?   My intent here is to get the two
> mags as physically close as possible without interaction to insure
> identical environments for more accurate comparison of the two mags.
>
> Jules
>
>
> On 11/1/2020 3:01 PM, David Witten wrote:
>
> Hello all,
>
> I apologise for not being very responsive lately.  I have been plodding
> along slowly, but some days have been much better than others for getting
> stuff done.
> I have been testing boards against the known-good boards returned to me by
> David McGaw.  This has been very helpful.
> I have been working on containment like Jules is using, but I'm using 2
> inch Schedule 40 white PVC pipe and fittings.  I'm using this because
> Scottie's magnetometer board is wider than any of the early prototypes, and
> I'm hoping this will serve for all cases.  I'm eager for any discussion on
> what the 'standard' should be.  I hate to deviate from what jules is using,
> but somehow it seems inevitable.  I hope that this is not an impediment to
> getting comparable results.
> The 2 inch pipe fits nicely in the largest hole made by the drill-based
> garden auger set I bought.
> The first hole I have made is about 2 meters (maybe less) from the
> foundation of my house.  I will need to get someone to help me when I put a
> hole at the full distance from my house, because my lot is currently too
> steep for me to navigate.  At that point, my installation will also be in
> shaded woods.
>
> My feeling is that we should get as many of these in the ground and
> measuring as possible, especially in situations where we can compare the
> measurements apples to apples.
> I'm sure that we badly want to know at least three things:
> 1) Inter-sensor variability in identical settings.
> 2) Inter-sensor variability in somewhat different locations.
> 3) How do Scotties boards compare to the prototypes we have.
>
> I'd like to hear any suggestions folks feel we should pursue.
>
> Dave Witten, KD0EAG
>
>
>
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