eLoran test 6 Feb for almost 2 months
In message CAD2JfAjSGrpoj5TJtB7uNeoAPng5zJUKLCJM2Kkgfp-pD8aOTA@mail.gmail.com, paul swed writes:
John absolutely 1 frequency 100 KHz. The repetition rate is 89700 us. Its
pulse and you need about +-15KHz BW. If listening its just a ticking sound.
Instead of your SDR it might be smarter to use either a digital
oscilloscope or spectrum analyzer.
You will need a frequency of exactly 1/0.089700 us = 11.14827201... Hz.
(HP5359A's are great for this, but most DDS sig-gens will work too.
You use this to signal to trigger your scope/spectrum analyzer, feed the
antenna signal to the input and select averaging mode.
If you have a really good antenna signal and a scope/spec-an with high
X-resolution, you can halve the sync frequency and, so that the pulse
polarity does not cancel out about half the loran pulses.
--
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
phk@FreeBSD.ORG | TCP/IP since RFC 956
FreeBSD committer | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.
On 02/03/2017 09:53 AM, Bob Camp wrote:
With reasonable gear, you can pick up the European Loran chains in
the US on a regular basis. You can also pick up the Russian system
that runs on the same frequency. The gotcha there is that you are
looking at “skywave” rather than “ground wave” signals to some
degree. That degrades their value for timing or for navigation. (Yes,
it is all a lot more complicated that than very simple / quick
summary).
Oh wow, I did not know that LORAN reception is adequate over such long
distances. So Chayka is essentially compatible with Loran-C frequency
transfer receivers? And is it still online? If so, it could be used as
a fallback in the unfortunate case that eLORAN R&D projects in the US fail.
-Ruslan
In message e5ec7150-1fb4-bd31-07ed-45cd1ce6fcf3@gmail.com, Ruslan Nabioullin writes:
On 02/03/2017 09:53 AM, Bob Camp wrote:
You can also pick up the Russian system
that runs on the same frequency.
"Chayka" on GRI 8000 is almost useless, I'm told this is so
even in Russia, because the GRI is an integral multiple of
1 millisecond, which means that you cannot average out CW
signals on integral kHz frequencies.
--
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
phk@FreeBSD.ORG | TCP/IP since RFC 956
FreeBSD committer | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.
Hi
The Russian system runs an incompatible pulse format. A “normal” Loran receiver
pretty much pukes when you try to tune to the Russian chains. It also is a bit unclear
just how stable their system is timing wise.
For timing you need ground wave. Anything that is more than 1,000 miles away is
not going to do much good in a timing system. To me this is one of the basic issues
with a eLoran system that only operates out of a single location. I’m happy with it if
it’s in the north eastern part of the US. I’d be really bothered if the only transmit location
was in Nevada ….
Yes once upon a time I had data on the Iceland chain as received in Ohio. I did it more
as a “because I can” than anything else. There were periods that things looked ~ok and
lots of gaps where they didn’t look very good at all. If I had not already calibrated the
local standard against a nearby chain … no way to figure out which data was correct.
Bob
On Feb 4, 2017, at 3:05 AM, Ruslan Nabioullin rnabioullin@gmail.com wrote:
On 02/03/2017 09:53 AM, Bob Camp wrote:
With reasonable gear, you can pick up the European Loran chains in
the US on a regular basis. You can also pick up the Russian system
that runs on the same frequency. The gotcha there is that you are
looking at “skywave” rather than “ground wave” signals to some
degree. That degrades their value for timing or for navigation. (Yes,
it is all a lot more complicated that than very simple / quick
summary).
Oh wow, I did not know that LORAN reception is adequate over such long distances. So Chayka is essentially compatible with Loran-C frequency transfer receivers? And is it still online? If so, it could be used as a fallback in the unfortunate case that eLORAN R&D projects in the US fail.
-Ruslan
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On 02/03/2017 10:02 AM, paul swed wrote:
Ruslan
NH will be easy to pick it up. The core frequency is 3 Cesiums in a
cluster. As for time transfer it can but its really a pain in the
backend and that information is indeed in the data channel. So make
us jealous with your CS and RBs. :-) I am down in Franklin Ma so we
are actually close compared to others.
I'm actually jealous of your LORAN time/frequency metrology capability
:). Apparently UrsaNav (headquartered locally in North Billerica, MA!)
are the ones performing these particular aforementioned R&D efforts; I
have visited their corporate website and have read about their projects
and product portfolio, and have developed a liking for this company
(despite being anarchosocialist). The reason is that philosophically
I'm a strong advocate of resilient technology and social policies, and
consequently that is the entire purpose of my nonprofit time/frequency
metrology and transfer project. As an example, the redundant
timekeeping and NTP transfer minicomputers will be provided with 7--10
WWV and CHU channels received with redundant auto-failover HF antennae,
just in case some channels fail (and that is in addition to redundant
GPS and of course the set of redundant UPS-, solar-, and
generator-backed standards, which hopefully will grow to there being a
fused ensemble of two modern Cs standards at any one time, rather than
the current scheme of the VXI-based controller simply running one at a
time in an auto-failover configuration).
-Ruslan
Hi
For NTP grade timing, there are still a lot of broadcast sources out there.
You do need to be careful about propagation and when to (not) use
them during the day. Focusing effort on that part of it is probably more
useful than waiting for funding to appear for eLoran….
Bob
On Feb 4, 2017, at 11:51 PM, Ruslan Nabioullin rnabioullin@gmail.com wrote:
On 02/03/2017 10:02 AM, paul swed wrote:
Ruslan
NH will be easy to pick it up. The core frequency is 3 Cesiums in a
cluster. As for time transfer it can but its really a pain in the
backend and that information is indeed in the data channel. So make
us jealous with your CS and RBs. :-) I am down in Franklin Ma so we
are actually close compared to others.
I'm actually jealous of your LORAN time/frequency metrology capability :). Apparently UrsaNav (headquartered locally in North Billerica, MA!) are the ones performing these particular aforementioned R&D efforts; I have visited their corporate website and have read about their projects and product portfolio, and have developed a liking for this company (despite being anarchosocialist). The reason is that philosophically I'm a strong advocate of resilient technology and social policies, and consequently that is the entire purpose of my nonprofit time/frequency metrology and transfer project. As an example, the redundant timekeeping and NTP transfer minicomputers will be provided with 7--10 WWV and CHU channels received with redundant auto-failover HF antennae, just in case some channels fail (and that is in addition to redundant GPS and of course the set of redundant UPS-, solar-, and generator-backed standards, which hopefully will grow to there being a fused ensemble of two modern Cs standards at any one time, rather than the current scheme of the VXI-based controller simply running one at a time in an auto-failover configuration).
-Ruslan
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