It should be obvious that the band was pretty good during this session, particularly if you were bound by the Pacific ocean. I don’t recall a night where JA reception reports were so plentiful and strong for so many stations. In Europe, DK7FC and DJ0ABR enjoyed rare reports from UA0SNV, which is a very long distance for a signal to cross over land. Trans-Atlantic reports were even present which is not often seen in sessions where the band is so good in other regions.
Part of this may have been the quiet but elevated geomagnetic conditions which may have provided enough “spark” to allow these opening to flourish. Solar wind was elevated during this session and Bz was more variable than it has been in a few days. Joe, NU6O / WI2XBQ, noted very strong conditions on 40-meters over the previous sessions where conditions were also strong on 630-meters. I suppose it is safe to say that there are variables that impact both bands positively and negatively and sometimes they can cross over.
VE3OT was audible here in Texas during the evening. I found Mitch by accident as I was preparing to call CQ on 474.5 kHz CW when I heard his beacon on frequency. Mitch has recently been on 475 kHz and its unclear whether this relocation was accidental or intentional but I will continue to monitor before I call CQ on CW and adjust my frequency accordingly.
Mark, WA9ETW, reported heavy QSB on Mitch’s signal which seemed to vary inversely with my signal strength. Ken, SWL/K9, in Indiana also noted that Mitch’s signal was down a bit and snow QRN was up. I suppose the band was long, which explains why I was hearing Mitch so well again.
Larry, W7IUV / WH2XGP, like several others, received reports from JA1NQI-2 during this session. Larry also reports that he decoded nine unique stations and was decoded by 42 during the session.
WSPR participation was very high, with 88 MF WSPR stations observed at 0335z. Regional and continental WSPR breakdowns follow:
There were no reports from the trans-African path.
Vasily, UA0SNV, received DK7FC and DJ0ABR across a very long land path:
EA8/DL9XJ and EA8/LA3JJ continue their activity from the Canary Islands.
DK7FC is reported in North American on the trans-Atlantic path at WE2XGR and VE3IQB.
Eden, ZF1EJ, was alone in the Caribbean during this session and provided reports across North America and Hawaii.
Laurence, KL7L / WE2XPQ, had the distinction of being received by six JA stations overnight. He also reports that there was a WSPR upload problem that he has since corrected. WG2XXM was decoded a total of nine times after 1100z.
In the Pacific, Merv, K9FD/KH6 / WH2XCR, experienced the return of the JA path as well, in addition to VK reports.
In Australia, Phil, VK3ELV and Roger, VK4YB, received a few reports from Japan and Hawaii.
Additional statistics, anecdotes, information and comments:
Ken, K5DNL / WG2XXM, reports that he decoded nine unique stations and was decoded by 42 stations in a session that was abbreviated due to overnight storms. I too experienced high winds and QRTed at 0630z until near sunrise out of an over abundance of caution.
Toby, VE7CNF, reports that he decoded eight unique stations and was decoded by thirty, including first time reports from VE3IQB, WB8ILI, and VE4BJZ.
Ken, SWL/K9, in Indiana sent the following comments and recommendations about setting audio levels after the large number of phantom spots were observed in the previous session:
Its probably a good time for all of us to check our sound device settings to ensure that they are operating properly.
Jim, W5EST, provided the following Part 2 discussion entitled, “IONOSPHERE SURFACE TEXTURE AND DRIFT FROM 630M SNRs”:
“Today let’s look at the subject of ionosphere surface texture and drift from a phasing viewpoint. I emphasize that my posts yesterday and today are 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.
As we know, if portions of a 630m RF signal reach the receiving antenna from different paths, the signal portions add if they are in phase, subtract if they’re out of phase. More generally, they “add” like arrows tip to tail and oriented based on their phase relationship. A perfectly flat, horizontal, motionless E-region would only reflect at the midpoint of a hop to connect the TX and RX stations.
If the E-region is dynamic, and not perfectly flat and horizontal in the middle of the night, then two or more reflections of the planar 630m RF signal’s wavefront at places not far from the path midpoint may come into the picture. See the illustration. Reflections from different places will generally have different path lengths.
In short, today’s picture involves multipath fading with its phase differences of reflections. It’s not unlikely the reflections will have similar amplitudes since the reflections occur near the path midpoint. With similar amplitudes in play, relative phases can do their work to significantly vary SNRs as the dynamic E-region contours slowly warp and drift.
I tried estimating how far “Δx” from the path midpoint would put a second reflection 180° out of phase on 630m. (Request the derivation if you like.) The result was Δx ~ sqrt(λd) where λ=630m and distance d is the great circle distance from TX to RX. For a d=900km path, Δx ~ 25km. that’s a lot more than the value Δx ~ 1.5km that I calculated yesterday, so you can see that today’s picture is a rather different one from yesterday’s.
How much would the ionosphere have to tilt relative to horizontal at path midpoint, to deliver a second reflection into the RX? Answer: Not much.
I got: Tilt Angle = 0.5° = 2 x 57° hE Δx / d2
For the 900km path with 150km E-layer height hE and Δx ~ 25km, that works out to a half-degree Tilt Angle ½°.
The ionosphere is already somewhat curved on average due to the curvature of the earth. Earth’s radius RE is 6371km. That angle of earth curvature at 25km away from path midpoint works out to one-fifth of a degree:
Earth Curvature Angle =0.2° =57° Δx / (RE + hE).
The Net Tilt at 25km relative to a perfectly horizontal ionosphere at that displaced location would be
Net Tilt Angle = 0.3° = 0.5° tilt – 0.2° due to earth curvature.
So where’s the net tilt coming from? Remember from yesterday that we’re talking about curved contour surfaces of electron concentration. I think the surfaces are departing from horizontal due to some kind of internal motion like convection and not from waves of compression. The reason I say so is that compression waves travel at the speed of sound regardless of whatever deeply subsonic frequency they might have. The speed of sound— ~600 m/sec in the ionosphere–is roughly comparable to its 300 m/sec speed at ground level. The speed seems far too fast to explain why 2200m SNRs vary so much more slowly than 630m SNRs. Physical geometry of the ionosphere is the same on both bands. Compression waves would move along Δx ~ 25km in 40 seconds on 2200m just as fast as on 630m. So it seems unlikely that compression waves could explain the usual nighttime variations in SNRs we see on these bands.
Let us know any better info you may have. Thanks!”
Additions, corrections, clarifications, etc? Send me a message on the Contact page or directly to KB5NJD <at> gmail dot (com)!