[time-nuts] Re: long term eLORAN time-transfer monitoring results?

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Regarding the current eLoran rollout for timing, it seems like UrsaNav has the only hardware that interacts with the timing signal.

They had one of their boxes on display next to a BPS (Broadcast Positioning System) display at NAB earlier this year, getting time over the eLoran signal and comparing it to BPS (which itself was being received by an area TV station's ATSC3 transmission, which I believe had time set via GPS at the transmitter).

I wrote up a bit about it (with a link to UrsaNav's info) in a recent blog post: https://www.jeffgeerling.com/blog/2025/bps-gps-alternative-nobodys-heard

-Jeff Geerling

> On Aug 2, 2025, at 10:48 PM, paul swed via time-nuts <time-nuts at lists.febo.com> wrote:
> 
> Jean I did see your post and not sure how to answer it.
> If you're in the US there are 3 eLORAN sites operational in the western US.
> Several of us have been monitoring the transmissions with Austron receivers
> and automatically logging the details 24 X 7 Rodger (Fellow time-nut)has
> done the most monitoring. We are both on the East Coast.
> The eLORAN signals have been on the air for about 18-24 months now.
> GRI 59900
> Site references are HP5071 cesium with backup units hot switched if needed.
> Here is why I haven't responded.
> As far as time transfer goes there should be something in the eLORAN data
> channel. But no one that I know is decoding that.
> They are not doing the old loran C TOC. So I don't see a way to answer your
> question.
> With respect to the frequency and propagation, that is logged and our local
> references are things like GPS, Rb, and CS references.
> Various plots do show the propagation changes. An alternate consideration
> is the vlf 60 KHz wwvb signal. It behaves the same pretty much.
> Assuming you are in North America.
> Hope this helps.
> Paul
> WB8TSL
> 
>> On Fri, Aug 1, 2025 at 4:17 AM Bob Camp via time-nuts <
>> time-nuts at lists.febo.com> wrote:
>> 
>> Hi
>> 
>> There’s a lot of data on Loran propagation from “back in the day”. Start
>> digging in around 1960 or so and you should turn up a number of papers.
>> Propagation for eLoran is no different than the good old Loran-C signals.
>> 
>> Simple answer: Back when we used it for timing, you picked a time of day.
>> You looked at things “at that time” each day. The same “pick a time of day"
>> was true for WWVB. The main advantage for Loran was more stations ment you
>> might be able to find a shorter path from you to the station you used.
>> Something around midnight or noon generally were popular choices for “that
>> time”.
>> 
>> Bob
>> 
>>> On Jul 31, 2025, at 10:28 AM, jeanmichel.friedt--- via time-nuts <
>> time-nuts at lists.febo.com> wrote:
>>> 
>>> After reading again
>> https://febo.com/pipermail/time-nuts_lists.febo.com/2023-May/107744.html
>>> I was wondering if anyone had some long term (> 1 month) record of time
>> transfer over eLoRAN,
>>> especially how day/night ionosphere impacts the 100 kHz delay, and how
>> the eLORAN station
>>> oscillators are disciplined.
>>> 
>>> Thanks, Jean-Michel
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