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OFF AIR - but back tonight after dark for more CW

Trans-Atlantic opening returns for first time since early April with WH2XXC -> G8HUH; Trans-Pacific openings very similar to previous session; W5EST presents ”Part 2: 630m Sunrise SNR Seasonality”

– Posted in: 630 Meter Daily Reports, 630 Meters

The details for July 5, 2016 can be viewed here.

IMPORTANT REMINDER: Neither 630-meters nor 2200-meters are open to amateurs in the US yet.  Please continue to be patient and let the FCC finish their processes.  Click here to view the proposed “considerate operators” frequency usage guide for 630-meters under Part-97 rules that was developed with the input of active band users.

Noise conditions were not much different from the previous session in North America with very similar regions experiencing ongoing storms.  Morning lightning activity was probably more wide spread than the previous session.

11-hour North American lightning summary

 

Geomagnetic conditions were also about the same, remaining at very quiet levels.  The Bz is currently pointing to the North and solar wind velocities are averaging near 320 km/s.  DST values continue to ride the centerline, perhaps trending to more positive levels on peaks.

 

 

 

Its been a few months since I reported trans-Atlantic openings but this session was graced with a single report for WH2XXC by G8HUH, which can be viewed here.  This behavior is not extremely abnormal as we have observed in previous years brief mid-Summer openings that yielded a handful of reports over the span of a few weeks.  Whether it is actual favorable propagation or European stations actively listening for North America is unclear.

Phil, VE3CIQ, reported that he heard six WSPR stations and he was heard by ten unique stations.  Phil indicates that lightning noise remains high.

Neil, W0YSE/7 / WH2XSV, reported a routine night, decoding three WSPR stations and he received reports from nine western stations including WH2XCR.  Neil added that he has “been decoded by John, VE7BDQ, 24+ hours now, day/night at 373 km.”

Larry, W7IUV / WH2XGP, provided reports for four WSPR stations and he received reports from sixteen unique stations.  As W7IUV, Larry provided reports for five WSPR stations.

WH2XGP session WSPR activity (courtesy NI7J)

 

Mike, WA3TTS, submitted this overnight report:

“Best DX over night was a single WH2XGP decode at….

09:18   WH2XGP   0.475688   -25   0   DN07dg   5   WA3TTS EN90xn   3227   89

I tried listening different directions, perhaps I should have listened longer to SW and QRN was higher to NW in mid evening.

Others decoded were XXP, XXM XRM, XUF, CIQ, AA3GZ(WH2XNG), and XXC. No decodes of WH2XND overnight on 2200m.

As mentioned, WH2XXC was decoded by G8HUH at 0228.  I noticed stronger than average signals from XXC both just before and after XXC was decoded by G8HUH…his other decodes were more in the -6 range with occasional decodes around 8~12dB stronger

01:52   WH2XXC   0.475648   +7   0   FM18qi   5   WA3TTS EN90xn   382   31
02:28   WH2XXC   0.475647   -27   0   FM18qi   5   G8HUH IO81mg   5730   50
02:34   WH2XXC   0.475648   +5   0   FM18qi       WA3TTS EN90xn   382   311″

 

Trans-Pacific report details, excluding KL7 and KH6, can be viewed here.

Hideo, JH3XCU, submitted these tables showing peak S/N and number of reports for DX -> JA for the session.

Roger, VK4YB, reported “High QRN from storms in the Tasman sea, which are likely to hang around for a few more days.  I noticed the TA spot and was hoping for a lift in the Pacific area, but it was all very average here. What happens in the Atlantic seems to be uncorrelated with our conditions.”  Roger received reports from 7L1RLL4 and he shared two-way reports with WH2XCR.  He provided reports for ZL2AFP.

Ward, K7PO / WH2XXP, received reports from 35 unique stations including VK2XGJ, VK4YB, ZL2BCG, and ZL2AFP.

WH2XXP session WSPR activity (courtesy NI7J)

 

Regional and continental WSPR breakdowns follow:

North American 24-hour WSPR activity

 

European 24-hour WSPR activity

 

Japanese 24-hour WSPR activity

 

Oceania 24-hour WSPR activity

 

Eden, ZF1EJ, provided reports for two WSPR stations and he received reports from five unique stations including WH2XCR.

ZF1EJ 24-hour WSPR activity

 

Laurence, KL7L / WE2XPQ, provided reports for one WSPR station and he received reports from three unique stations including WH2XCR.

WE2XPQ 24-hour WSPR activity

 

Merv, K9FD/KH6 / WH2XCR, provided reports for WE2XPQ, ZF1EJ, and VK5FQ.  He shared two-way reports with VK4YB and he received reports from VK2XGJ and ZL2AFP.  Merv’s DX report details can be viewed here.

WH2XCR 24-hour WSPR activity

 

Jim, W5EST, presents “Part 2: 630m Sunrise SNR Seasonality“:

“In Part 1 on Monday, its Figure 2 compared 7 months-apart sunrise regime SNRs on the 35w WH2XXP-n6skm path, heading 303°, distance 925 km.    http://njdtechnologies.net/070317/  . Today I’ll try to explain them.  Today’s illustration helps show why all this happened, in my opinion.  Explanation numbers correspond to the summary numbers next.

Q1)SR-SR interval between WH2XXP and n6skm RX station sunrises was cut approximately in half between late fall 2016 and beginning of summer 2017.

A1) Terminator moves westward as the earth rotates eastward. However, from season to season the orientation of the Terminator changes.  The more the path heading departs from East-West, the more the seasonal orientation of the Terminator affects the time interval that elapses between SRs at the eastward station and the westward station.   Because the XXP-n6skm path is NW/SE, SR in June can reach N6SKM in a shorter elapsed time after SR at XXP in Arizona, than it did in November.

Q2)Night to day SNR dB dynamic range between Nov. 30 and June 24 appears to have widened about 4 dB, from 33 dB to 37 dB down.

A2) In the summertime after sunrise the sun moves quickly up more nearly in the zenith direction than it does in late fall and early winter. For that reason, the down-ramp rate in SNR dB/hour is faster in the summer than 6-7 months prior. Also, the sun’s ionizing radiation is more concentrated due to the higher angles after sunrise that the sun attains in summertime compared to the opposite months of the annual cycle.  The pre-SR dB SNRs were higher in June, and TX or RX antenna changes might have occurred.  It’s the SNR dB difference or range that’s primary focus of this explanation.

Q3)For November 30, AZ SR has its SNR position far above the blue “halfway line.”  June 24 instead shows the SNR at AZ SR well below the red halfway line.

A3) Referring back to today’s illustration, the sun’s ionizing rays at altitude reach perpendicularly well beyond the apparent line of the terminator on the ground.  This was discussed and diagrammed in this blog April 18:  http://njdtechnologies.net/041817/   .

In today’s illustration, the sun’s rays begin to ionize the D-region and ramp its absorption at the orange colored intersection areas on either side of the red-circled mid-path reflection between the stations.  When the rising sun’s heading last November was nearly aligned with the path, meaning the terminator was perpendicular to the path, the sun’s rays were more delayed reaching these D-region places where relevant absorption can occur. Less signal absorption happened as of the moment of Arizona sunrise in late fall and early winter on this path heading.

However, for other path headings even in the same region, I’d expect seasonality to be different.

Likewise, which of N. or S. hemisphere will matter too.  TABLES 1 and 2 summarize my current opinions about the seasonality of different paths at sunrise in the N. and S. Hemisphere respectively.

It may take a little while to concentrate fully on the TABLE entries. Considering one path example in one season at a time can make your reflection bit easier.  For instance, the entries in the N. Hemisphere TABLE 1 cell in June column for the NW/SE row can apply to XXP-n6skm path. They say “Earlier,  Shorter,  Lower SNR,  More Absorpt.”  Compared to other times of year they say that SR happens earlier, and the interval between station sunrises is shorter.  SNR at Eastward station sunrise SR is positioned lower on the SNR downramp graph.  The range of night-to-day SNRs indicates More Absorption in the D-region in daytime relative to nighttime in summer.

See if your accumulating experience turns up some seasonal counterexamples now or in the future, so the Tables can be revised as appropriate.  For instance, I looked up 5w XGP-n6skm, heading 190°, distance 1090 km. Behavior on that path did not fit the TABLE 1 entry for NE/SW very well: Subject to lots of missing decodes, the 6/17-30/17 database gave one SR decode at high SNR on the downramp one day and some other days rather low SNR on an incomplete downramp or indeterminate.  This may suggest that TX powers typical of most 630m TX stations may suffer so much randomness that the Tables wouldn’t be very practical.  Oh well.

The focus is on 1-Ehop and 2-Ehop 630m paths, and I’ve not tried to deeply consider longer paths and transoceanic DX paths, where very little of the sunrise dynamics appears on the database anyway.  Nor have I here fully considered high latitude sunrise seasonal SNR behavior where the concept of “sunrise” becomes more vague when it occurs at all and the sun heading more rapidly changes during this regime.

I look forward to any comments. Your contributions matter.  TU & GL!”


Additions, corrections, clarifications, etc? Send me a message on the Contact page or directly to KB5NJD gmail dot (com)!