Hello all, I'm a recent recruit to this list, it looks very interesting
and I hope I can make a contribution. Though now retired I'm an
electronics & radio engineer and until last March worked for u-blox
(though not on the GNSS side of the business).
Looking at their product integration guide
Hi,
I agree.
In general, you have one 50=>75 transmission loss, cable damping, one
75=>50 reflection, cable damping, a 75=>50 reflection, cable damping,
75=>50 transmission for the direct path of 50=>75 transmission, cable
damping 75=>50 transmission. Thus, the reflection will be two cable
d
Hi
Relay based attenuator. Oddly enough I have data on more than one generator :)
(ouch indeed if it’s not being paid for on somebody else’s credit card)
Bob
> On Nov 22, 2016, at 10:50 AM, Scott Stobbe wrote:
>
> Ouch! Relay stepped attenuator? Or solid state components?
>
> On Mon, Nov 21,
Ouch! Relay stepped attenuator? Or solid state components?
On Mon, Nov 21, 2016 at 11:00 PM Bob Camp wrote:
> Hi
>
> There are packages you can put on a fairly standard HP signal generator
> that will
> do the mismatch stuff without spending all the money Sperient wants for
> one of
> their mach
Hi
There are packages you can put on a fairly standard HP signal generator that
will
do the mismatch stuff without spending all the money Sperient wants for one of
their machines. One suggestion: If you *do* go with the HP solution, running
the
attenuator up and down to simulate fast fades (th
I haven't used one personally but a spirent gps simulator would let you do
a try it and see.
It will be interesting to see if out of the growing sdr community an open
source gps simulator emerges.
On Mon, Nov 21, 2016 at 1:01 PM Dr. David Kirkby (Kirkby Microwave Ltd) <
drkir...@kirkbymicrowave.c
On 11/21/16 3:11 PM, Attila Kinali wrote:
On Mon, 21 Nov 2016 14:36:49 -0500
Bob Camp wrote:
The reflection issue ahead of the antenna is a reflection of the signal from
a single satellite. The multipath
reflection makes that satellite appear to be further away than it really is.
In the case t
p...@phk.freebsd.dk said:
> I think the installation manual for Trimbles timing products say you can use
> either 75 or 50 Ohm cable...
I think they suggest using RG-6, the classic cable TV and/or satellite dish
cable. It's widely available at low cost.
The loss due to impedance mismatch is m
On Mon, 21 Nov 2016 14:36:49 -0500
Bob Camp wrote:
> The reflection issue ahead of the antenna is a reflection of the signal from
> a single satellite. The multipath
> reflection makes that satellite appear to be further away than it really is.
> In the case that the reflected
> signal is *s
Sorry... I pressed the wrong button while editing the Mail and cut short...
Continuing where I left off
> In the case of a mismatched cable, there is no “single satellite” issue.
> Everything is impacted by the mismatch.
> Even if the mismatch is pretty bad, the “primary” wave is the one that
I believe that reflections inside the cable (that is, after the antenna)
are very different from reflections before the antenna. GPS receivers do
their calculations based in the different arrival times of the
satellites signals to the antenna center, so delays caused from
different paths caused
In message
, "Dr.
David Kirkby (Kirkby Microwave Ltd)" writes:
>Whilst the input impedance of the antenna input terminal on a GPS receiver
>is probably marked 50 Ohms, I'd be somewhat surprised if it was very close
>to 50 Ohms. Antenna cables have an impedance, which is typically 50 +/-
I believe that reflections within the cable doesn't matter regarding
the GPS measurements, unlike the reflections coming from outside the
antenna. The measurements are made from the differences in the arrival
times of the different satellite signals to the antenna and delays after
that basical
Hi
Based on extensive testing of the line mismatch issue, the answer turns out to
be “it does not matter”.
The reflection issue ahead of the antenna is a reflection of the signal from a
single satellite. The multipath
reflection makes that satellite appear to be further away than it really is.
People state it is desirable to have a GPS antenna well clear of
obstructions, which I believe is to stop reflections. But there is another
source of reflections which I suspect could be just as problematic.
Whilst the input impedance of the antenna input terminal on a GPS receiver
is probably mar
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