For a second night my station, as well as others, was QRT due to weather. While storm noise dictated that remaining QRT was probably just as well, a number of stations report a nice, almost typical session. Geomagnetic conditions remained quiet with a stable Bz and solar wind in the low category.
Nicolas, F4DTL, reported his first 630-meter QSO with Scotland, as he completed a QRSS3 QSO with GM3YXM. QSB was strong at the beginning of the QSO but conditions improved near the end.
David, GM3YXM, sent the following screen capture and reports that Nicolas was a strong RST 559.
John, WA3ETD / WG2XKA, had a QRP adventure during the session:
John added in a follow up email that band conditions in the East were quite strong, in some cases uncharacteristically so. John’s QRP outing is consistent with my observations when the band is good. While “this ain’t 20-meters”, a good band can allow low power to go a long way. Don’t get hung up on the idea that you need kilowatts. Its just not true.
Neil, W0YSE/7 / WG2XSV, operated JT9 during the session and reports best receive signals for VE7BDQ at -5 dB S/N at 0742z, VE7CNF at -1 dB S/N at 0844z, and WI2XBQ at +4 dB S/N at 0938z. During this same interlude, Toby, VE7CNF reported Neil at -21 dB S/N at 0506z. Laurence KL7L / WE2XPQ, observed the activity and sent the following contents of his receive window:
Regional and continental WSPR breakdowns follow:
There were no trans-Atlantic or trans-African reports during this session.
In spite of noise in the southern and eastern US, Eden, ZF1EJ, and Roger, ZF1RC, did a good job hearing the stations that were on the air. Eden even reported WG2XKA’s QRP signal.
In Alaska, Laurence, KL7L / WE2XPQ, was not transmitting again in order to focus on some VLF reception work but he did report a few stations, including Merv, K9FD/KH6 / WH2XCR.
In Hawaii, Merv, K9FD/KH6 / WH2XCR, experienced a bit of a down session from the US mainland where noise and storms resulted in many stations off air during the session. Merv did better in the Pacific, where the usual suspects in VK and JA were present.
Phil, VK3ELV, had the following session reports from Hawaii and Japan.
Additional statistics, comments information and anecdotes:
Jim, W5EST, provided the following description of a concept that he has been developing for a long time to predict propagation:
“4-QUADRANT DIAGRAMS IN 630M PROPAGATION PREDICTION
Today, 630m propagation prediction is front and center. This is a tough topic. How can we get some prediction techniques, or at least some testable and predictive rules of thumb?
Like any really hard project, one needs first to prepare the workspace and sharpen the tools. Tooling is what today’s blog item is about – specifically, a method for testing propagation predictions.
I’m going to borrow an analogy from the medical field. Picture a pregnancy test that supposed to give a plus + when one is actually pregnant, and a minus – when there’s actually no pregnancy.
You could look at 630m propagation like that! Yes, 630m and pregnancy make only a remote analogy. But go a little way and work with me here. 🙂
630m is “pregnant” for DX or not on a given night. 630m is pregnant for daytime sky wave or not on a given day. Yes, some judgement could be needed to characterize in-between propagation conditions. And you can get more specific about which part of the world or which part of the country you are considering.
Suppose we actually came up with some candidate predictors for 630m propagation prediction. They would likely resemble formulas stating numerical conditions on solar weather and/or geomagnetic field and/or some type of specified reception rate hours beforehand or perhaps a day prior.
How would we test a candidate 630m propagation predictor? One method uses a 4-quadrant 2×2 table illustrated in blue with columns that signify whether 630m is “actually pregnant” plus (+) or minus (-), and rows that signify whether the propagation technique indicated “630m pregnancy predicted” plus + or minus -. The 2×2 table has various hypothetical numbers of nights (or daytime days instead) from which you can tell how well a hypothetical test works.
Propagation on the 630m band has a characteristic feature that desirable things like nighttime DX or daytime sky wave are less-frequent occurrences. So, for the hypothetical test, I’ve entered a relatively small number of 20 “true positive” days predicted positive and actually positive and a relatively large number of 55 “true negative” days predicted negative that were actually negative.
At lower left are tabulated 7 days predicted negative but actually were positive. These analogize to false negatives in medical jargon. 630m was “pregnant” but the 630m pregnancy test mistakenly showed minus “-” for those seven days.
Opposite at upper right lie 18 “false positives”: days 630m was “not pregnant” but the 630m pregnancy test mistakenly showed plus “+” for those days. (Of course, medical-commercial pregnancy tests should do far better than this!)
Believe it or not, these hypothetical table entries represent what for 630m propagation prediction would constitute a very powerful test–probably beyond our 630m state-of-the-art just now. One would enjoy 3 times as many good 630m sessions (3:1) compared to the number missed by QRT relying on negative prediction. Moreover, the operator would have at least a 50-50 chance (20:18) on any positive-predicted session of it turning out to be actually positive.
Whether any propagation prediction method we can come up with approaches this quality level or not, I suggest that we at least “set the bar” according to both requirements of this 2-fold test:
P+(+) > 3.0 P-(+) #True positives exceed 3.0 x #False-negatives. (False neg rate < 25%)
P+(+) > 1.0 P+(-) #True positives exceed 1.0 x #False-positives (Precision or PPV > 50%)
Because of our current inability to predict 630m propagation, dogged persistence night after night has become a necessary virtue. And the 630m community can rightly be proud of that persistence so many non-USA hams and Part 5 USA station operators and RX-only ham operators display.
Is predicting transoceanic 630m nighttime openings an unnecessary luxury if stations are transmitting or receiving to reach nearer stations in their own region anyhow? Then transoceanic predictions would mainly be useful only to enable or encourage stations to do any last-minute optimizations or antenna heading adjustments beforehand, rather than decide whether to activate in the first place.
Regarding daytime 630m sky wave propagation events, on the other hand, only a few of us can arrange to keep TX or RX stations running day after day to test for daytime prop. And the rest of us may find it difficult in the daytime even to follow a reflector to see if daytime prop occurred for some station pair, not to mention get our own station activated in response.
On that basis, creating a 630m daytime propagation prediction method could be useful. To create it we’d gather what historical information we can assemble on daytime 630m propagation and compare it with some 630m daytime propagation prediction method candidates to see what works. Easier said than done?
Can you offer any candidate predictor either in words or as a formula? Let us know! TU & GL.”
Additions, corrections, clarifications, etc? Send me a message on the Contact page or directly to KB5NJD <at> gmail dot (com)!