Another thought, perhaps the difference is between the quality of the
oscillators.
The Resolution T has an ordinary XO while the NTBW50AA has an OCXO
(possibly defective).
I would expect the XO to be noise like in a stable temperature
environment. The OCXO, if defective,
may have semi-controlled excursions from it's design frequency. However,
I don't know
if the 10 MHz of the OXCO is used by the GPS chip and could therefore
affect the calculated
position.
Pete.
On 1/7/2017 4:31 PM, Peter Reilley wrote:
In my case (the original post) there can be no multipath difference,
same antenna and done at the same time.
The length of the cables from the amplified splitter are about the
same; within inches.
This must be some difference in the receiver, perhaps in the math?
Pete.
On 1/7/2017 4:16 PM, Bob Camp wrote:
Hi
In terms of multipath at GPS frequencies, a couple of inches is a
*lot*. Also unless you have
pretty good antennas (as in much larger than 1” each) they will have
phase issues unique
to each antenna. Phase cancellation and addition is what gives you
multipath.
Bob
On Jan 7, 2017, at 4:00 PM, Gary E. Miller <[email protected]> wrote:
Yo Bob!
On Sat, 7 Jan 2017 15:16:34 -0500
Bob Camp <[email protected]> wrote:
The “simple” answer is that the weird legs going out from the central
blob are the result of multi-path / reflections in the received
signal. With enough data you might be able to correlate them to
observed obstructions.
I have lots of data from GPS with the antennas mounted 1 inch apart.
They show different weird legs, so I suspect that local
geology/architecture
is not the whole story.
For example, compare the plot I just sent, to the one attached here.
Two GPS right next to each other, very differently looking plots.
I'll admit to never generating plots over the same time interval, I'll
start a 24 hour test of two GPS right now.
RGDS
GARY
---------------------------------------------------------------------------
Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703
[email protected] Tel:+1 541 382 8588
Veritas liberabit vos. -- Quid est veritas?
"If you can’t measure it, you can’t improve it." - Lord Kelvin
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