630-meters had a lot to offer during this session. While openings seemed slow in the East from my station in Texas, the band got significantly better as the evening progressed. Later openings are a feature of longer days as the Earth begins to tilt closer to its Spring and Summer positions in the northern hemisphere.
Some interesting early openings did occur on the transcontinental path, as Steve, VE7SL, reported that VE3OT’s CW beacon was audible nearly two hours before sunset in British Columbia. Larry, W7IUV / WH2XGP, reported Mitch’s audible signals at 0200z and periodically through the evening. Mitch was curiously not audible here in Texas during the evening, which is abnormal since he has been heard here most nights that he has been active this season. Mark, WA9ETW, reported that Mitch’s signal was down from typical levels during the evening and also reported that my WSPR CW ID was RST 589 at 0252z. There was lots of variability in the band.
There was a moderate amount of QRN from storms in the south eastern US during the evening but that noise tapered off as the evening progressed. It was obviously not enough of a problem to prevent Doug, K4LY / WH2XZO, in South Carolina, from decoding DK7FC’s WSPR’s multiple times. As Jim, W5EST, noted in the ON4KST chat/logger, imagine what the S/N reports might have been like with no QRN! QSB was also a feature but it was generally insignificant. Larry, W7IUV / WH2XGP, and I completed JT9 and JT65A QSO’s during the evening and even with variable signal levels, QSO’s were still easy to complete.
As a side note, I typically preach that because of the narrower bandwidth of JT9, it is more suitable for a 7-kHz wide band. Larry notes that JT65A is actually somewhat better when conditions are unsettled. I will have to examine this more closely. While JT65A is considerably wider, Larry’s signal was audible in spite of being outside of the usual S/N range for audible signals, particularly in USB receiver bandwidth!
The geomagnetic field was quiet but elevated at points during this session. Protons also were elevated during the late afternoon in North America while the Bz was variable. Solar wind velocity was also elevated to moderate levels in excess of 460 km/s.
John, WA3ETD / WG2XKA, experienced an early weather-related shut down but had a strong session while he was transmitting and submitted the following report:
Neil, W0YSE/7 / WG2XSV, reported that he would be operating QRSS3 during the evening on the 600-meter research group email reflector and followed the QRSS activity with WSPR. Neil provided the following comments:
Peter, VK4QC, posted the following information on the VK 600-meter email reflector about on-going activity with Roger, VK4YB, and anyone else interested in joining them:
“We’ll be up on 472.5 CW nightly from 0900 UTC then QSY 479 LSB for a while”
WSPR activity was very good, with 82 MF WSPR stations observed on the WSPRnet activity page at 0220z. KP2XX was listening briefly but its possible that storm QRN from the south eastern US prevented him from hanging around for the duration. John, WA3ETD / WG2XKA, reported that the path to Cayman Island opened later than normal. Reports from Jim were just not meant to be this night.
Regional and continental WSPR breakdowns follow:
There were no reports from the trans-African path. UA0SNV was present from Asiatic Russia but no reports were found in the WSPRnet database.
Stefan, DK7FC, once again corners the market with trans-Atlantic reports. He was decoded by WE2XGR, and WH2XZO:
Eden, ZF1EJ, and Roger, ZF1RC, were present and providing reports from the Cayman Islands. Eden reported WH2XCR:
Its always a good session for Laurence, KL7L / WE2XPQ, when he is reported in Japan.
Merv, K9FD/KH6 / WH2XCR, received a few reports from John, VK2XGJ, and Roger, VK4YB, while providing reports for Roger and Phil, VK3ELV. The path to Japan appears to be cut off again. This might be related to an approaching weather system that Merv reported yesterday. Larry, W7IUV / WH2XGP, reported that Merv was still being decoded an hour after sunrise in Washington state.
Phil, VK3ELV, received reports from Japan, Hawaii, and Larry, W7IUV / WH2XGP in Washington state. It is believed that this is the first reception report of a WSPR station in Australia by a station in the mainland US. Also notable is that neither station is really close to salt water on the great circle path. Larry reports that he was using an EAST -facing BOG that was only 600-foot long. So was the signal really coming out of the East or was Phil simply so strong that F/B did not matter? Jim, W5EST, reports that storms in Phil’s region may have prevented him from hearing Larry for a two-way report.
Additional comments, statistics, anecdotes, and information:
Ken, K5DNL / WG2XXM, reports that he decoded eight unique stations and was decoded by 45 unique stations.
Jim, W5EST, provided the following discussion entitled, “ESTIMATING IONOSPHERE SURFACE TEXTURE AND DRIFT FROM 630M SNRs”
“This post is intended more to provoke your thinking rather than be reliably correct. If you have some experience, some words of wisdom, or some book or article on this topic, e-mail us at this blog.
Let Δt represent a time interval between successive 630m 2-minute WSPR transmissions. In the nighttime regime WSPR SNRs can vary significantly–sometimes 5 to 10dB from slot to slot. Here’s an example: 5w WG2XXM-no1d (OK-AZ) 0500-0758z on a 1399km path on Feb. 27, 2016. One XXM transmission every 4 to 6 minutes is the Δt time interval here. The SNR sequence for this one-hop path far from storms ran along as follows:
-4+1+0 -7 -6-13-7 -8 -2 -1+1+4 +4 (0500-0556z)
-2 -4 -1 -1 -4-12-5-11-12+0-4 -8 -13 (0602-0658z)
-5 -1+0 +0-7 -4 -5 -3 -2+0-2+0 +1 (0702-0802z)
Suppose the ionosphere was slowly changing in place, like the surface of water slowly coming to a boil. Also suppose the reflecting ionosphere halfway from OK to AZ was moving horizontally in some direction as a mass.
Picture quilt-like clouds on an overcast day. The ionosphere could have a somewhat globular, cloudy texture of the plasma as “seen” by 630m RF. The texture is the imperfectly flat shape of the electron concentration contour surfaces. These surfaces enable sufficiently strong (and weak) 630m reflections to deliver the SNRs that the WSPR decoder generated at NO1D in Arizona.
I surmise that the minimum size scale of curvature of this texture is roughly 2λ, two wavelengths of 630m, perhaps 1500m of globular surface. That would be sufficient to offer plenty of surface area for reflection while also being sufficiently coarse so 630m signal SNRs would vary as much as they do.
Moreover, 630m SNRs vary substantially and rapidly on the scale of minutes. By contrast, 2200m SNRs vary much more slowly and deliberately on a scale of a half hour or more. That suggests ionospheric texture variation that’s coarse to 630m and less-coarse to 2200m. The size scale of curvature in this texture is closer to the 630m wavelength than to the 3 times longer 2200m wavelength.
Suppose the ionosphere is moving near the place(s) of 630m reflection with a velocity v and has a somewhat globular texture having a spatial scale of Δx. Then for the SNR to vary greatly during time interval Δt, at least one of the globular surfaces must present different parts of its surface to accomplish this. To estimate what the speed v might be under this assumption, I write a speed formula and substitute some plausible values:
v ~= Δx / Δt (“~=” means “about equal.”)
Δx = ~1500m, that is, more than 2 wavelengths of 630m
Δt = ~ 6 minutes = 0.1 hour
The rough value Δt is the time scale of fast-varying 630m WSPR SNRs on single-hop paths.
The SNR variations might be due to slow changes of the texture without any motion. Consequently the velocity could also be less than the estimate here.
v ~= 1500m / 0.1 hr
v ~= 15 km/hr or 9 mph.
This rough estimate suggests that the ionosphere as 630m sees it, most likely the E-region, can be slowly drifting in the deep nighttime. What do you think?”
Additions, corrections, clarifications, etc? Send me a message on the Contact page or directly to KB5NJD <at> gmail dot (com)!