[time-nuts] Trueposition Antenna Location

[MLewis]

On 03/12/2018 10:56 AM, Mark Sims wrote:
> There is something seriously wrong with your antenna/cable...  With an M8T and GPS/GLO/GAL I typically track 20-28 satellites.  With a crappy indoor antenna I can track 10-15 sats.
>
> ------------------
>
>> With GPS, GLO & GAL, the M8T-10 was averaging 4 satellites, max 9, min
> 0, regularly below 2, often 1, and a too high number of times it hit zero.

Mark,

My bad.

I forgot to say that the count I was reporting is the green sats in LH. 
Those sats with a strong enough signal and the ublox tags them as 
available-for (used in?) the 'solution'. I forget the name of the setting.

With that and my skyview, the difference in your count vs. my current 
counts makes sense to me.

I have less than half of a sky view.
- Less than a 180 sweep of azimuth (building, window frame).
- Less than 90 of elevation (window frame, buildings up from horizon 
across from the antenna).
- Plus the portion of that blocked by the roof over the entrance and its 
supporting poles.
Plus tons of multipath from multiple buildings, electrical cables, metal 
poles & cars. (the road in the attached is actually a parking lot, cars 
nose in on each side with two lanes down the middle)

Three layers of congregated steel above me, one for each floor/story, 
each held a layer's worth of concrete while it originally cured. Plus 
steel mesh in the walls. The view between those layers to the 180 
degrees to the 'North' are blocked by buildings at the same or different 
height with the same construction; so the distant view out from between 
those layers is largely blocked.

BUT, when the M8T was sitting on its board on the table, in 3D position 
mode it was reporting a somewhat wide 3D range. The M8T-10 stayed within 
200 m of me and largely on a "track" (while a few years ago the M8T-01 
wandered as far as 2 km between S and SE). When the board was put in an 
insulated aluminum bottle (fairly thick wall), the bulk of that 
wandering ended, and its intersection with the building at the upper 
left red tag is correct. In the bottle it did still go for a walk during 
testing. See attached.
In or out of the bottle, the reported altitude varied from 29 m to 69 m; 
actual is 80.032 m. This was before the 4" antenna 
re-position/cable-jostling. I haven't checked it on positioning mode 
since then.

Seeing how much it improved being moved 4" along the sill, from
 > averaging 4 satellites, max 9, min 0, regularly below 2, often 1, and 
a too high number of times it hit zero.
to
 > averaging 7 satellites, max 13, min 0, rarely below 3, hit 1 a number 
of times, hit zero once.
the difference could very well be the cable getting jostled. But that 
now transparent transformer is a neat trick.

Right now it sees/tracks twelve sats (reports a signal strength). Six of 
those are green. While writing this, the green have counted between four 
and seven. In the past 12 hours, green available/used: max 10, min 3.

Does that make it add up better?

Michael


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