A review of my session data suggests only an “OK” session here. Noise was elevated in spite of improvements in geomagnetic conditions. A few strategically placed storm systems no doubt had an impact on activity although activity seemed worse in the West where fewer storms were present compared to the East. Most of the S/N levels were consistent with JT9 QSO levels, even on shorter paths that normally yield single-digit or even positive S/N values.
Geomagnetic activity has returned to very quiet levels with the Bz hovering near unity and solar wind velocities in the low range below 400 km/s. There were a few periods of elevated protons reported during the session:
This morning’s CW sked yielded solid results as the new VFO provided very good stability. The original VFO, which showed signs of frequency instability and loss of power regulation yesterday, appears to be ok. The power source that has been used for years is really not suited for application where frequency stability is required. The original VFO will be kept as a spare since the new VFO has a much smaller foot print.
Ken, K5DNL / WG2XXM, reports high QRN levels and subsequently decoded two WSPR stations while being decoded by seventeen unique stations during the session. He also notes 22 decodes at WH2XCR with the best at -16 dB S/N.
Joe, VO1NA, continues to operate 5-wpm CW on 477.7 kHz. Roelof, PA0RDT, who often reports Joe’s CW, indicated that he had a PC problem that prevented reports during the previous session. Two sessions back Roelof reported Joe’s signal in spite of high noise levels.
Neil, W0YSE/7 / WG2XSV, reports a more challenging session than the previous and offers these statistics and comments:
Regional and continental WSPR breakdowns follow:
There were no reports from the trans-Atlantic, trans-Equitorial, or trans-African paths. UA0SNV and PU3VRW/SWL were present but no reports have been filed at this time. PU3VRW/SWL continues to report the old WSPR frequency but it remains unclear, even after emails, whether his receiver really is on the incorrect frequency or not.
In the Caribbean, Eden, ZF1EJ, reported WG2XXM and WG2XIQ:
Laurence, KL7L / WE2XPQ, reports that he decoded WH2XCR 22 minutes after his local sunrise. He also reported WG2XXM overnight:
Merv, K9FD/KH6 / WH2XCR, had limited reports from the Pacific Northwest, which is surprising given the amount of activity there overnight. Merv was reported in the south-central US in addition to Alaska and the usual suspects in Australia:
Jim, W5EST, presents, “REPRESENT DAYTIME PROPAGATION ON THE SNR BULLS-EYE DIAGRAM”:
“The June 15, 17, 20 blogs illustrated SNR bulls-eye diagrams of somewhat-cyclic daily and annual features of 630m propagation. One could use an ordinary rectangular graph of SNR vs. time to represent signal behaviors. However, a bulls-eye diagram more satisfactorily represents the cyclic diurnal or annual nature of much LF/MF propagation dynamics, I believe.
For purposes of those blog posts, a time-independent outer power circle of radius PTX + GtxAnt + GrxAnt can encircle a bullseye diagram that has SNRTX-RX plotted through the time cycle. If noise is constant or small on a quiet receiving night, then propagation-related variations in dB path loss LPATH correspond to the varying radial graphical distance from an SNR curve outward to the power circle.
The SNR at the bulls-eye center was flexible and established at some minimum guesstimated daytime SNR. Conceptually, all SNRs weaker than that are “below the bathtub drain” that reaches down to minus infinity dB (). Intuitively, one thinks of stronger SNRs as bigger in radius on the diagram. Thunderstorms depress or pinch SNR inward on the diagram, see June 17, this blog.
Some much for background. Today’s illustration turns the SNR bulls-eye diagram inside-out to invert the radial dB legends on its concentric SNR reference circles. One intuitively pictures a vintage radar scope image and now arranges the bulls-eye diagram so that weak signals now have their SNRs “farther out.” Likewise, one thinks of a bulls-eye center as the sought-after place on a target, which here would signify high SNR at the RX. So a strengthening signal brings SNR closer to the target RX “bulls-eye.” The SNR of the bulls-eye center now is legended +10dB (or whatever strong SNR you like). Plus-infinity SNR () is out of sight.
Intuition aside, inverting the dB legending on a bulls-eye diagram graphically magnifies weak SNRs and more conveniently represents their curves for propagation investigation. The SNR curves portray the nighttime SNRs of DX and transcontinental stations in purple and green beneath. In red, the often-weaker daytime SNRs of much closer regional stations traverse their daytime courses in the upper half of the diagram. One red curve for just one station is shown.
Multiple software instances for WSPR2, WSPR15, and QRSS can be opened on your computer to receive different stations transmitting their preferred deep-SNR probing modes. You can read more about QRSS technique in the June 1-4 posts to this blog.
Either way that SNRs might be ordered or inverted on a bulls-eye diagram, the left-right positions can also be reversed to represent 1) 24 hour clock time with sunset SS left and sunrise SR right, or instead as 2) SR left-SS right as shown, or 3) array the months of the entire year around the circumference for either global hemisphere.
We know very little about the very low SNR regimes that provide LF/MF DX and daytime propagation. Our aspirations reach through the 24-hour diurnal cycle and throughout each year. What do we know about these things over decades? Almost nothing. Be part of the amateur/experimenter efforts receiving and/or transmitting on LF/MF. Surprise the experts as well as your friends, extend our knowledge at short and long ranges, and show what the LF/MF community can do!”
Additions, corrections, clarifications, etc? Send me a message on the Contact page or directly to KB5NJD gmail dot (com)!