Hello Everyone,
Thanks for the feedback - I certainly have a lot to think about.
Seems eBay could be a preferred vendor for antennas. I don't need anything
too fancy - but I would like something that does OK in wind and rain, I
don't have to worry too much about snow at my current location -
Hi
Once the sat's all arrive at the antenna, a fixed delay (in general) does not
impact things a lot. The gotcha with the filter is that it's delay is unequal
across the GPS band. Doppler puts the sat's all over the place. That gives some
more delay than others. Having unequal delay on sats is
From: Bob Camp
Hi
Once the sat's all arrive at the antenna, a fixed delay (in general) does
not impact things a lot. The gotcha with the filter is that it's delay is
unequal across the GPS band. Doppler puts the sat's all over the place. That
gives some more delay than others. Having unequal
On 9/15/13 10:24 PM, David J Taylor wrote:
From: Bob Camp
Hi
All of the ones I've opened up or seen dis-assembled have had the
ceramic plate antennas in them. That very much surprised me early on,
since I *assumed* they had something fancy inside based on their shape.
No argument about the
On 9/16/13 6:03 AM, David J Taylor wrote:
I am thinking about exact time measurement - getting your PPS edge
exactly on the nanosecond. People can add in the length of the cable as
an offset, so they must also need to enter any delay through any
filters, mustn't they?
Agreed that for
From: Jim Lux
Of course they would factor all this in. That's why the UNAVCO site has
all the phase center locations and delay behavior for the various antennas.
===
Didn't know about:
http://www.ngs.noaa.gov/ANTCAL/
Jim, so thanks for that.
David
--
SatSignal
Alan,
Well, you shamed me into actually setting it up and measuring the IRQ
delay. Amazingly, the delay varies from 25 to 110 milliseconds, depending
upon what type of triggering is involved. I did the test using their
lightning simulator and measuring the delay between the magnetic pulse
the
Jim wrote:
Spectrum regulators know this, of course, and assign adjacent
services accordingly.
They do? Remember, it was the FCC that came up with the idea of
using the Mobile Satellite Service L-band downlink spectrum for
terrestrial broadband service in the first place (setting the stage
Hi Bob,
Doppler shift is +-3.5kHz.
Bandwidth for the CA signal is ca 2MHz, narrow correlator receivers takes
in 10MHz to mitigate multipath errors.
So doppler spread is about 1/1000 of the spread spectrum signal. Does the
filter delay really change that much with 7kHz total doppler variation?
Hi
On Sep 16, 2013, at 9:48 AM, Jim Lux jim...@earthlink.net wrote:
On 9/16/13 6:03 AM, David J Taylor wrote:
I am thinking about exact time measurement - getting your PPS edge
exactly on the nanosecond. People can add in the length of the cable as
an offset, so they must also need to
:-)) sorry Tom I couln't resist the dig but it looks like the result was
interesting and a little unexpected ! its always better to measure it
yourself, where possible, than rely on datasheets which can sometimes be
quite imaginative
Well done
Alan
- Original Message -
From: Tom
The AS3935 chip has a DSP on it that is doing a lot of statistical analysis.
It only draws a few microamps, so it's gotta be slow. I'd be VERY surprised
if the detection to output timing was even slightly deterministic.
Hello Everyone,
While we're on the subject - not to get too far off on a tangent - I have
been doing 'web-research' on this - but can someone recommend a great site
or reference for the specifications of the GPS signaling sent down by a GPS
satellite? For instance, I learned that PPS for a
With all the talk about choke rings, and having spent all my pennies elsewhere,
I looked around to see if there were any do-it-yourself versions. I found this
one: http://www.mauve.gr/var/DIY_Choke_Ring_GPS_Antenna.htm. Is it worth the
effort, other than as an experiment? Are there any other
It could be... It' s not hard to add nop's so that the detection always
takes the slowest possible time (but deterministic, or near).
Em 16/09/2013 20:36, Mark Sims hol...@hotmail.com escreveu:
The AS3935 chip has a DSP on it that is doing a lot of statistical
analysis. It only draws a few
I use galvanized stovepipe end caps; they can be cut and soldered. I
think the 6 inch is about right for 1520 MHz
Don
Bob Stewart
With all the talk about choke rings, and having spent all my pennies
elsewhere, I looked around to see if there were any do-it-yourself
versions. I found this one:
This response didn't make it to the list for some reason.
Hi Don,
Would you care to elaborate? Remember, I know nothing about this other than
what I can read on that guy's site. I guess I'm looking for ~63mm height?
What part are you talking about soldering? The seam? And what do you
On 9/16/13 6:43 PM, John C. Westmoreland, P.E. wrote:
Hello Everyone,
While we're on the subject - not to get too far off on a tangent - I have
been doing 'web-research' on this - but can someone recommend a great site
or reference for the specifications of the GPS signaling sent down by a GPS
On 9/16/13 9:13 AM, David J Taylor wrote:
From: Jim Lux
Of course they would factor all this in. That's why the UNAVCO site has
all the phase center locations and delay behavior for the various antennas.
===
Didn't know about:
http://www.ngs.noaa.gov/ANTCAL/
For what
Thanks Jim.
Best Regards,
John W.
On Mon, Sep 16, 2013 at 9:25 PM, Jim Lux jim...@earthlink.net wrote:
On 9/16/13 6:43 PM, John C. Westmoreland, P.E. wrote:
Hello Everyone,
While we're on the subject - not to get too far off on a tangent - I have
been doing 'web-research' on this - but
On 9/16/13 6:51 PM, Bob Stewart wrote:
With all the talk about choke rings, and having spent all my pennies elsewhere, I looked
around to see if there were any do-it-yourself versions. I found this one:
http://www.mauve.gr/var/DIY_Choke_Ring_GPS_Antenna.htm;. Is it worth the
effort, other
David J Taylor wrote:
GPS 18x PC/LVC 3.90 (August 28, 2013)
Folks, I have received notice of an update to the GPS 18x LVC firmware,
which can be downloaded here:
http://www8.garmin.com/support/agree.jsp?id=4055
...
Any reports would, I'm sure, be welcome.
Thanks for the firmware
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