Interesting how you only get three daytime stations, all under 500 km. I need to see what I can get here in the daytime.
I used to get more, but the U.S. Army Corps of Engineers decommissioned a few back in May-July. My favorite was St Paul, as it was strong throughout the day and when it was breaking up, I could tell bad storms or something was wrong. There were times when I thought my station might have a problem, but St Paul confirmed it was just propagation.
I just realized how much closer to Alaska you are. The Alaskan DGPS stations are mostly around 3,000 km from you, Kodiak is 4,167 km. Upolu Point, Hi is 6,285 km, I guess that is your furthest catch?
Yes, so far Upolu Point the furthest, at least that I've been able to confirm.
The west coast stations are around 3,600-3,800 km from me, Alert Bay is 4,016 km. Level Island Alaska (which I have heard) is 4,415 km from me, and Kokole Point Hawaii (which I have not heard) is 7,874 km. Azores is 4,122 km, and Madeira is 5,374 km. Portugal is 5,648 km and Helgoland Germany is 6,233 km, I think my furthest catch - a brief 19 second opening with 3 decodes, on a split channel which helped I am sure. Hmm, Koblenz Germany was also received once with 3 decodes but over 12 minutes. But also on a split channel. 6,385 km.
In many ways, the Alaskan stations are a similar distance from you as the west coast stations are for me. And Hawaii for you is about the same as Europe for me. Also these both are our longest distance catches, and they are very similar in distance. Your path to Hawaii has to travel over a bit of the US first before the Pacific Ocean, I have a shorter distance to the Atlantic, but then for stations from continental Europe there is a bit of land again. You do get Hawaii more consistently than I get Europe, and with many more decodes. A lot of this is a function of what other stations the desired target has to compete with (part of my motivation to build the loop)
Very true. A couple of things:
- Hawaii is a little lower in latitude than I am, so our daylight is about the same. Over in Europe, some of them are further north which means in summer, more daylight.
- For the path MN to HI, over middle of US then over water. For MN to EU, its a more polar route. For MD to EU, its still more polar than from MN to HI.
- Then there's MN to AK. All over land, and AK is way up north, but it comes into southeast AK. Still impact from polar conditions.
- With winter on the way, this will be interesting.
Q: How much does the polar impact LW/MW propagation?
I find it interesting how comparable the distances are, and whether they represent the maximum range possible.
Unknown, unless we had stations every 0.5 km in a full grid on the earth. Far too many holes in the DGPS stations.
There's also the transmitter power (and antenna pattern) of each of the stations. I believe Canada has coverage maps on their site. How many of these stations have omni directional antennas, how many are purposely directional, and how many are accidentally directional due to local terrain? I believe there is a west coast DXer that routinely gets DGPS from Australia. Quite a long haul, but if it is only over the ocean, that helps a lot.
This is one of the biggest factors. You can see from the CCG maps a great disparity in patterns (assuming they're accurate).
And then there's there's the ground between them & us.
Water (esp salt water) helps a lot. You can see that with some coastal U.S. MW stations and their patterns.
I need to read up a bit on MW/LW (DGPS sits right at the intersection of the two) propagation. I wonder what distance is covered by each hop, and is roughly 6,000 km a maximum because it is several hops already, and any further is attenuated too much?
Good question. At ~6km , daylight can't be far away on either end, esp when in summer. If we could turn the sun off for a couple of days...
Especially for the power level, I believe these stations are typically a few hundred watts. vs the megawatt (or at least hundreds of kW) that the broadcast stations use. NDBs are at roughly the same power as DGPS stations I think, although CW is going to be a more efficient mode. If only decoding of it over the entire band could be automated.
The power of NDBs and DGPS stations are roughly the same. I think the NDBs range from 25W to 1-2kW, with modest antennas.
The NDBs- There is the carrier + LSB + USB. That would be harder to decode. They're all on 1.0 kHz spacing, with US stations the MCW is at 1030 Hz. Canada is 400, IIRC. I don't know about doing the entire band at the same time, but if you pick some target stations, listen for the LSB+USB signals. If they match, then look for something midway that could be identified as a carrier, then lock onto that thing. Measure the carrier. If one sideband is lost, no big deal, listen to the other. If both are lost, then could no longer consider the carrier as ID'd. Or something like that. Measure the strength of the carrier & the sidebands (independently).
However, trying to decode weak CW may be hard, as an H may turn into an S. Which is one reason why I think fine resolution may not be possible. Would need to listen to the CW over time and determine its true ID vs problems from fading.
That should work, until you factor in multiple stations on the same frequency. Or even adjacent freqs since the 1 kHz spacing is pretty close to the 1.03 kHz spacing of the MCW.
Topic: DGPS Logs Aug 29, 2017 UTC 2306 - Aug 30, 2017 UTC 2312 (AFE822x) (Read 1466 times)