On 02/02/2017 01:59 PM, paul swed wrote:

So eLORAN, both the present experimental form and the expected future
standard, is completely forward-compatible?

-Ruslan

Ruslan,
Seems to be backward compatible. Yes.
All of my stuff works austrons and SRS 700.
Whats your location? The transmitter is in NJ and I am near Boston. So
somewhat close for me. My antenna is the standard boat preamp and whip
antenna. 6 foot off the ground.
Regards
Paul
WB8TSL

On Thu, Feb 2, 2017 at 7:55 PM, Ruslan Nabioullin rnabioullin@gmail.com
wrote:

I don't have a Loran receiver, and I live in Colorado. But I'd still
like to check late at night to see if I can see a signal on my SDR
receiver. I tried looking at old posts, and did some research online,
but the best I can tell is that Loran C (and I assume eLoran) is
transmitted at around 100 Khz. Anyone know precisely what frequency(s)
are used by the Wildwood eLOran station?

Regards,

John

On 2/2/2017 11:59 AM, paul swed wrote:

On 02/02/2017 09:47 PM, paul swed wrote:

Very exciting news!  I and my modest metrology lab is located in
southern NH.  But time transfer won't work, right?  I'm not interested
in LORAN-based frequency transfer due to my having a number of modern Cs
standards, Rb standards, a disciplined OCXO standard, and currently one
low-end (+/- 150 ns) GPS time and frequency receiver (the XL-AK).

-Ruslan

All Loran C signals are transmitted at precisely 100.00000... KHz.

They are a pulse signal system, where each member of the chain uses
a different repetition rate to time the placement of its pulses.

The repetition rates are designed so that they pulses from any
two chains are not coincident, but for random times, over very
long intervals.

There are numerous Wiki's, and other sources of information that
can be found by searching for Loran C.

-Chuck Harris

John Marvin wrote:

100 khz.

73,

Bill, WA2DVU

-----Original Message-----
From: time-nuts [mailto:time-nuts-bounces@febo.com] On Behalf Of John Marvin
Sent: Friday, February 3, 2017 1:21 AM
To: time-nuts@febo.com
Subject: Re: [time-nuts] eLoran test 6 Feb for almost 2 months

I don't have a Loran receiver, and I live in Colorado. But I'd still like to check late at night to see if I can see a signal on my SDR receiver. I tried looking at old posts, and did some research online, but the best I can tell is that Loran C (and I assume eLoran) is transmitted at around 100 Khz. Anyone know precisely what frequency(s) are used by the Wildwood eLOran station?

Regards,

John

On 2/2/2017 11:59 AM, paul swed wrote:

time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

Hi

Loran C is a pulse based system. All transmitters world wide run on the same 100 KHz frequency. The thing that
distinguishes one transmission from another is the repetition rate of the signal. If you have a spectrum analyzer
and hook up a piece of wire near one of the transmitters, the signal shows up over many 10’s of KHz of
bandwidth each side of 100 KHz. 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).

Bob

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.
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.
Regards
Paul
Swedberg

On Fri, Feb 3, 2017 at 2:08 AM, Ruslan Nabioullin rnabioullin@gmail.com
wrote:

In message 589490F1.4090902@erols.com, Chuck Harris writes:

Actually, they're not.

The envelope changes the frequency in rather interesting ways.  I used
to have a plot of it, but it seems to have disappeared into my
archives some time go...

Stick to the zero-crossings.

--
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.

In message CAD2JfAjSGrpoj5TJtB7uNeoAPng5zJUKLCJM2Kkgfp-pD8aOTA@mail.gmail.com, paul swed writes:

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:

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:

"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 02/03/2017 10:02 AM, paul swed wrote:

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