Rigolet, NL

[ChrisSmolinski]

Rigolet, NL has been a tough catch here, rarely appearing at all prior to Sallisaw going QRT on Dec 31st. These are the dates with at least one decode, all other dates had zero decodes:
Aug 22-23: 10 decodes - this was the first night I ran Amalgamated DGPS, I think.
Sep 13-14: 1
Dec 4-5: 2
Dec 17-18: 4
Dec 20-21 1

Here are the decode counts since then:
Jan 1-2: 6
Jan 2-3: 62
Jan 3-4: 0
Jan 4-5: 27
Jan 5-6: 0
Jan 6-7: 0
Jan 7-8: 0
Jan 9-10 0
Jan 10-11 42
Jan 11-12 877
Last night (Jan 12-13) I had 4093 decodes

Please explain to me how longwave propagation works  

I took a look at A and K index values, and don't see a strong correlation:
#                Middle Latitude        High Latitude            Estimated
#              - Fredericksburg -     ---- College ----      --- Planetary ---
#  Date        A     K-indices        A     K-indices        A     K-indices
2016 12 15     2  0 0 1 1 1 1 1 1     1  0 0 0 1 1 0 0 0     3  1 1 1 1 0 0 1 1
2016 12 16     2  1 1 0 0 1 1 0 1     0  1 0 0 0 0 0 0 0     3  1 1 0 0 0 0 0 1
2016 12 17     3  1 0 0 1 1 1 2 2     3  0 0 0 0 2 1 2 2     6  1 0 1 1 1 1 2 3
2016 12 18     6  2 3 2 1 1 2 1 1    11  2 3 3 1 4 3 1 1     9  3 3 3 2 2 2 1 1
2016 12 19     5  1 2 1 2 2 1 2 0     7  0 0 3 3 3 2 1 0     5  1 2 2 1 1 1 2 1
2016 12 20     4  1 1 1 2 1 2 0 2    11  0 1 3 5 1 3 1 1     6  1 1 1 2 1 2 1 3
2016 12 21    18  2 2 2 3 3 5 4 3    36  1 1 2 5 5 7 4 3    23  2 2 1 3 4 6 4 4
2016 12 22    15  4 4 3 3 2 2 3 2    38  4 3 6 6 5 4 3 3    23  5 4 4 3 3 3 4 3
2016 12 23    17  3 4 3 3 3 2 3 4    37  3 4 5 6 5 4 4 4    24  4 4 3 4 3 4 4 4
2016 12 24    10  3 2 3 2 2 3 2 1    27  3 2 5 5 5 4 3 2    14  3 3 3 2 3 3 2 2
2016 12 25    12  3 3 2 2 3 3 3 2    27  2 1 2 6 5 4 4 3    21  4 4 2 4 4 4 4 3
2016 12 26    15  4 3 3 2 3 3 2 3    45  4 4 5 6 6 6 2 2    22  5 3 3 3 4 4 3 3
2016 12 27     8  3 3 1 2 2 1 2 2    12  3 2 1 4 4 2 2 1    11  4 3 2 2 2 1 2 3
2016 12 28     4  1 2 0 1 1 2 1 1     5  1 2 0 3 1 2 1 1     6  2 3 1 1 1 2 1 2
2016 12 29     2  2 1 1 1 0 1 0 0     9  1 1 1 4 3 3 1 0     5  2 1 1 1 1 2 1 1
2016 12 30     2  0 1 0 0 1 0 1 1     1  0 0 0 2 1 0 0 0     4  1 2 0 1 1 1 1 1
2016 12 31    10  1 2 1 3 3 3 3 2    21  0 0 1 5 5 5 3 2    12  1 2 2 3 3 3 3 2
2017 01 01     9  3 3 3 2 1 2 1 1    26  2 4 4 6 5 2 2 1    14  4 4 3 2 2 3 2 2
2017 01 02     5  1 3 1 1 2 1 1 0    23  1 2 6 4 5 3 1 1     7  2 3 2 2 2 2 1 1
2017 01 03     8  0 1 2 4 2 2 2 2    24  1 1 2 6 5 4 3 2    12  1 2 2 4 3 3 3 3
2017 01 04     8  1 1 2 2 2 2 3 3    13  1 1 1 4 4 2 3 3    11  1 2 2 2 2 2 4 4
2017 01 05    15  3 3 2 2 3 3 3 4    23  3 3 3 1 5 5 4 3    18  3 3 2 2 3 4 4 4
2017 01 06    14  3 4 3 2 3 2 2 3    28  4 4 5 4 5 3 4 2    16  4 4 3 2 3 3 3 3
2017 01 07    14  3 2 2 2 4 3 3 3    37  3 2 5 4 7 4 3 3    20  4 3 3 2 4 4 3 3
2017 01 08    11  3 3 2 2 2 2 3 3    26  2 2 3 6 4 4 4 3    16  3 3 2 3 3 3 4 4
2017 01 09     8  3 2 2 1 3 2 1 2    20  4 2 1 3 6 3 2 2    12  4 2 2 2 4 3 2 3
2017 01 10     5  1 1 2 0 1 2 2 2     9  1 1 2 2 3 3 3 1    10  2 2 2 1 1 3 3 3
2017 01 11     7  3 2 2 1 1 2 2 1     7  1 2 2 0 3 2 2 2     8  3 2 2 1 1 2 2 2
2017 01 12     3  1 2 0 0 2 1 1 1     0  0 1 0 0 0 0 0 0     5  2 3 0 0 1 0 1 1
2017 01 13    -1  1 1 0 0 1-1-1-1    -1  1 1 0 2 2-1-1-1     4  1 1 1 1 1-1-1-1

I also looked at the DST index, and again nothing obvious jumps out.

This is a coverage map of the DGPS stations in the Maritimes:


The patterns certainly help explain why Rigolet is a tough catch here, although the others are much more regularly received. I am looking for an explanation of the differences in propagation from night to night, and how this might help us better understand LF/MF propagation overall.

[ChrisSmolinski]

As an update... there is a curious pirate logging from this morning. There were two stations on 6925, but it seems one of them (the one playing piano music) was being heard at the same time (1430z) in NY and CA. That's pretty unusual propagation for 43 meters at that time of the morning.

[jFarley]

Please explain to me how longwave propagation works  

And then you can explain it to me.  It is exceptionally fascinating.  "The numbers" in general seem to tell me when props are going to be bad.  "The numbers" may give an indication as to when props might be good.  No matter what "the numbers" seem to say, you still have to play the game.  "The numbers" - and the Blitzortung map - just give a hint of where to set my recording span for the night given a list of targets I need.

Last night from the NDB side:

Several central USA reporters ment generally good props to most directions.  The DST trend since 11Jan17 has been upwards and looks like it may continue to improve even more given no sun farts.  The DK0WCY magnetometer plot was flat and stable during the overnight period.  Both of these would suggest good props.  But to where?

From Chicago I experienced good props to the East.  I logged a few in NY and PA, and a fairly common beacon in Buffalso was in all night w/o break.  AB and  SK had strong signals at times.  But the best props came from a band above Hudson Bay, from about 2300 to 3500 km and many beacons in upper NU and QC were noted or logged.  The beacons a bit farther to the south in these provinces, not so much.  Were they skipping over me?  Dunno.  Props were OK to the SE, but nothing unusual noted.  Props were good to TX early on, but seemed to peter out in the morning hours.

https://www.hfunderground.com/board/index.php/topic,31582.0.html

I would like to find a comprehensive and authoritative and believable discussion of what really occurs during long haul LW propagation, particularly with regards to factors which can enhance or diminish propagation.  There seems to be a lot of opinion and apochrypha on the internet, and I haven't found what I am looking for yet.

[ChrisSmolinski]

It's so unpredictable, even on days with bad geomagnetic field numbers, sometimes you get interesting catches. I wonder how subjective our relationship between the various indices and actual propagation is - do we remember the times they correlate the way we expect them to, and forget about the times they don't?

I'd like to find a way to objectively compare the DGPS decodes and various indices and other numbers, and see if anything resembling a science can be established. As of now I feel we'd be better off examining entrails.  To me, that means something automated. I think there's potentially some interesting data in the reams of DGPS decodes, especially if data from multiple listeners could be used. When I observe an opening to station X at time Y, what are other listeners hearing? Someone 50 miles away, 500 miles away, and 1,000 miles away? Anything at the same time? Or a few minutes before or after?

One problem with the DGPS stations vs CW beacons is that the DGPS decodes at any given time are limited to one station. To hear station A, not only must it propagate to your QTH, but station B (and maybe C and D as well) on the same frequency must also NOT propagate to your QTH. So if you're not hearing A, it doesn't mean A isn't reaching you, but perhaps B has a stronger signal. That's the reason I added the graphing window to ADGPS, so for a given frequency you can observe patterns of stations fading in and out. Even though Annapolis on 301 kHz is only 81 km away, I can still sometimes get decodes from Angleton, TX over 2,000 km away. Not many, but a few each night, usually in a short burst. The best theory I have so far is that there is some sort of destructive interference that is nulling out Annapolis for that brief period of time, perhaps a sky and ground wave cancelling each other out? I recall reading that MW stations suffered from an effect where listeners tens of km away could not hear them due to such mixing of ground and sky waves, at certain times of the day. In the Annapolis/Angleton case, it may also help that one uses 100 and the other 200 baud. Since DGPS is MFSK, each baud rate uses a different shift.

[PirateSWL]

As an update... there is a curious pirate logging from this morning. There were two stations on 6925, but it seems one of them (the one playing piano music) was being heard at the same time (1430z) in NY and CA. That's pretty unusual propagation for 43 meters at that time of the morning.

I thought the broadcast was odd myself. The music made the people talking very difficult to understand and I doubted someone would produce something like that. Wasn't sure if 2 people were transmitting at the same time with the same signal strength or the person broadcasting was mixing the music and OM/YL skit together. Either way it was a tough hear, no better then S3 in the beginning then quickly dropped to no signal at all within the first 10 minutes.

[skeezix]

I recall reading that MW stations suffered from an effect where listeners tens of km away could not hear them due to such mixing of ground and sky waves, at certain times of the day.

Yes.

I was talking with a US MW broadcast engineer (now retired, but managed a few 50kW flamethrowers over the decades) earlier this year and he mentioned this exact thing. IIRC, it was around 25 miles. Its not full cancelling, but can definitely hear the interference. Some stations configure the antenna to decrease the skywave.

There is a 50 kW day/25 kW at night that's about that far away and under some conditions, I do hear the cancelling. Its not full cancelling, but enough to be noticeable. It sounds kind of like selective fading on SW.  Currently listening on an old 1928 Radiola with a 25' long wire, and can't notice it. But, when I listen on the SDR with either a loop or omni, I can very clearly hear it. The Radiola has 2 knobs and a switch, so of course it knows what to do. A Sony ICF-2010 with its internal loop and an external loop also shows the ground & sky wave interference.


As far as the propagation of Rigolet-  Numbers are inconsistent with what we know and it seems magical. Which means, that there is another (or multiple) factors ... to be discovered. Is it another set of numbers that we collect but haven't associated with this? Is it weather? Some other phenomenon? Was Chuck Norris nearby?

I agree that we should analyze the decodes that we have. I've been saving mine. Also need to pull the solar data & keep that. One thing that really should be confirmed (for better scientific analysis), is that the stations are putting out the stated power & directivity. Has the USCG or CCG measured the signal strength around their transmitters, instead of using modeling? I've seen some reports they make, and they drive down a highway. While that's good, that's not fully around the station.

Definitely need more receive sites.

Now that Sallisaw is decommissioned  , will the USCG will sell the site, and could we get an FCC experimental license for the band? Then we can put it on its own frequency with no one else and feed it data that is consistent and predictable. Continuous transmission of a short, useful message with a mode that has high confidence of the integrity of the message. For extra credit, switch to RTCM SC104 with our own select data instead of satellite corrections and compare its robustness.

Would like more than one of these sites, however, scatter a few in various parts of the country, incl HI, AK.


This is exciting.

[ChrisSmolinski]

As far as the propagation of Rigolet-  Numbers are inconsistent with what we know and it seems magical. Which means, that there is another (or multiple) factors ... to be discovered. Is it another set of numbers that we collect but haven't associated with this? Is it weather? Some other phenomenon? Was Chuck Norris nearby?

I need to read up on how propagation in this band is supposed to work. DGPS is really right on the line between LF and MF. Perhaps it has its own modes and patterns of propagation. In absence of any other data, I'm going with the Chuck Norris theory.

I agree that we should analyze the decodes that we have. I've been saving mine. Also need to pull the solar data & keep that. One thing that really should be confirmed (for better scientific analysis), is that the stations are putting out the stated power & directivity. Has the USCG or CCG measured the signal strength around their transmitters, instead of using modeling? I've seen some reports they make, and they drive down a highway. While that's good, that's not fully around the station.

Definitely need more receive sites.

Now that Sallisaw is decommissioned  , will the USCG will sell the site, and could we get an FCC experimental license for the band? Then we can put it on its own frequency with no one else and feed it data that is consistent and predictable. Continuous transmission of a short, useful message with a mode that has high confidence of the integrity of the message. For extra credit, switch to RTCM SC104 with our own select data instead of satellite corrections and compare its robustness.

Would like more than one of these sites, however, scatter a few in various parts of the country, incl HI, AK.

This is exciting.

It is indeed exciting, I think there is a lot to learn and discover here.  An experimental license on a single frequency, but with a large number of stations operating on a time slotted basis, could also be a lot of fun. That would allow folks to park a single conventional radio on the channel and decode. Even Fansome could do it, knobs and all. How easy it is to actually get said license is another story. There is the 160-190 kHz LOWFER band, you get a watt and 50 ft of antenna wire. With some sort of good error correcting code you might be able to make it work?

[skeezix]

I need to read up on how propagation in this band is supposed to work. DGPS is really right on the line between LF and MF. Perhaps it has its own modes and patterns of propagation. In absence of any other data, I'm going with the Chuck Norris theory.

It is indeed exciting, I think there is a lot to learn and discover here.  An experimental license on a single frequency, but with a large number of stations operating on a time slotted basis, could also be a lot of fun. That would allow folks to park a single conventional radio on the channel and decode. Even Fansome could do it, knobs and all. How easy it is to actually get said license is another story. There is the 160-190 kHz LOWFER band, you get a watt and 50 ft of antenna wire. With some sort of good error correcting code you might be able to make it work?

This band, straddling LF & MF (but the definition is arbitrary, nothing magical happens at 300 kHz) is reminiscent of 220 MHz. If you're used to 2m & 70cm, suddenly 1.25m is an oddball. How does D, E, F1, F2, F (night) impact DGPS band? How about sporadic-E? Is there a different mode that hasn't been discovered yet that enhances the LF/MF freqs, but not HF and above? Right now, its kinda like predicting how a cat will behave.

The time slot freq sharing would be good, but it has to be in sub-second sharing (e.g. TDMA). Then less of a chance to miss something. However, would still prefer to have dedicated stations with continuous transmissions, at least to start. Which got me to thinking... Chopping it up into digital bits could still miss something. Is there an analog solution that would capture everything? But, how to determine that vs noise. Modulate the carrier with a distinctive pattern that will not occur in nature nor with QRM. This requires far more thought.

Would like a bunch of these things scattered across the country (incl AK, HI, and if possible, including PR & Guam) also near & on the poles.

160-190 is good idea, but that's 2/3 - 1/2 the frequency of DGPS and propagation is probably significantly different there. That would be a separate experiment from DGPS. Sticking a few transmitters down there, along with stations in the 283.5-325 band would be very useful. Ideally at the same site. Since I'm asking for the moon here, put a set of tx down around 85 kHz, 400, 515, and 1720.  If the LORAN-C stations are decommissioned, borrow some of their sites (with our own tx) and retune to just below the LORAN-C bandwidth (so as to not interfere with Dana, Seneca, and others that may come back online). Would like to go further down from 85 kHz, but antennas will be large, difficult & expensive. Maybe the USN could help us and when they're not sending messages on 25.2 kHz, they can transmit unencrypted messages for us.

With that said, we can do 160-190 now. I think we should at least try. But 1W into 50' at that frequency will be very weak. I've dabbled there in the past (rx only) and only found one beacon. Way back in the late 80's or early 90's, the USAF had their GWEN stations around there. Those are long gone now. In fact, it looks like the USCG was able to get those old sites and use them for DGPS.