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Probably QRT tonight and in the morning due to storms in the area

Very similar session to previous as very quiet geomagnetic conditions persist; W5EST presents ”Ski Jump SNR: Interpreting XXP/XND-n6skm 630m D-Region Sunrise”

– Posted in: 630 Meter Daily Reports, 630 Meters

The details for July 31, 2016 can be viewed here.

IMPORTANT REMINDER: Neither 630-meters nor 2200-meters are open to amateurs in the US yet. That includes stations using fake or pirated call signs. Please continue to be patient and let the FCC finish their processes. UPDATED: 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.

It was a much quieter night on the East coast and Midwest which was reflected in reports for this session.  Parts of the Desert Southwest and central Canada continue to be “under the gun” and this morning I am hearing a number of lightning crashes in the distance here in North Texas.  Its not a bad morning for noise here in spite of storms within 500 miles of my QTH.

11-hour North American lightning summary


Geomagnetic conditions remain quiet to very quiet during this session.  The Bz is pointing slightly to the South and solar wind velocities are averaging near 340 km/s and continues to trend downward.  DST values pushed into positive territory for persistent periods on indicators in both hemispheres.




Ken, K5DNL / WG2XXM, decoded five WSPR stations and he received reports from 48 unique stations including E51WL, WE2XPQ, WH2XCR, ZF1EJ, and six Canadian stations.

Larry, W7IUV / WH2XGP, provided reports for eight WSPR stations and he received reports from 34 unique stations. As W7IUV, Larry provided reports for eight WSPR stations.

WH2XGP 24-hour WSPR activity (courtesy NI7J)


Neil, W0YSE/7 / WG2XSV, reported, “I was truly “whispering” this session. Had to rely on my MF Solutions transverter completely due to a problem with my IRF540 class D/E amplifier. These spotters of my 200 mW ERP were still able to pull out some decodes of my WSPR beacon. Even Laurence, XPQ in AK was able to decode me TWICE (-21 & -23). Pretty good for the end of July especially at this power level. Had I been able to run my normal 1.85w ERP, all these reports would be about 9 dB higher.

I was pleased to see that I had received 10 decodes of XPQ (AK) which ranged from -21 to -31 dB.  Hope to get the amplifier back on line soon. Thanks to all who decoded my “rewop” (power spelled backwards 😉 )”

David, N1DAY / WI2XUF, reported:

“Conditions seemed almost like winter time last night here in Western NC.  Air was cool and clear – and very much unlike usual atmospheric conditions here at this time of the year.  I continue to have success with my single coil inductor design  inspired by Doug Allen’s (WH2XZO) design and was surprised to generate a station best-ever performance again last night with 32 spots over a 12 hour period.   I now have 76 radials of various lengths in my ground plane and am seeing a lot less SWR variation as we transition between wet and dry conditions.  Hopefully that will continue.”

Dave, N4DB, indicated improved band conditions with very low QRN.  He provided reports for nine WSPR stations including session best WH2XGP at a distance of 3489 km.  Dave added that ZF1EJ was decoded as usual but his signal was down a bit, peaking at -27dB S/N.

Al, K2BLA / WI2XBV, reported “some noise this AM” but during his one-hour listening session he reported nine WSPR stations.

Mike, WA3TTS, reported:

“Another night of reasonably good summer propagation, although I noticed the QRN was getting higher around 0600.  Dual band 630m/2200m receive,  NE and SW directions before 0400, NW direction after 0400. Ten stations decoded on 630m.  I did some maintenance on my EWE ground system Sunday afternoon. Uncertain if that helped with the higher than normal XSH/15 spots count and somewhat improved XGP SNRs versus propagation factors.”

David, AC4IU, submitted this graph of WSPR data received at his station in Virginia overnight:

Trans-Pacific report details, excluding E51, KL7 and KH6, can be viewed here.

Hideo, JH3XCU, submitted this link detailing DX -> JA spot totals and peak S/N, as reported on the Japanese language 472 kHz website.

Roger, VK4YB, reported “Heavy QRN at the start of the session, easing a little later. Propagation improved and JA path was restored.”  He received reports from 7L1RLL4, JA1NQI/2, E51WL, VE6XH and WI2XBQ.  He provided reports for WH2XXP and he shared two-way reports with WH2XCR.

Ward, K7PO / WH2XXP, received reports from 51 unique stations overnight including E51WL, ZL1BPU, ZL2AFP, VK4YB and VK2XGJ.

WH2XXP 24-hour WSPR activity (courtesy NI7J)


I spent the early part of the evening listening on 474.5 kHz CW, making a few calls but listening more than anything else.  In recent days I have had a few impromptu QSOs with a local, very close stations operating under my second station license but it was not meant to be during this session.  I plan on doing a lot of listening and chit-chatting this Fall and Winter on CW.  I’ve not made additional progress with CW Skimmer / RBN.  I seem to have a couple of nagging issues and just need to find time to dig into the Yahoo group for answers.

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 five WSPR stations. He received reports from nineteen unique stations.    It was a considerably better session for Eden and may have been the result of quieter weather conditions in much of North America.

ZF1EJ 24-hour WSPR activity


Warwick, E51WL, provided reports for seven WSPR stations by 1500z.  Those report details, excluding WH2XCR who is detail below, can be viewed here.

E51WL 24-hour WSPR activity


Laurence, KL7L / WE2XPQ, provided reports for five WSPR stations and received reports from twelve unique stations. He shared two-way reports with WH2XCR, WG2XSV, WH2XGP and WI2XBQ.

WE2XPQ 24-hour WSPR activity


Merv, K9FD/KH6 / WH2XCR, provided reports for eight WSPR stations including VK3HP. He shared two-way reports with VK4YB, WH2XGP, WI2XBQ, and WE2XPQ.  He received reports from E51WL, VK2XGJ, ZL1BPU, and ZL2AFP.  DX report details can be viewed here.

WH2XCR 24-hour WSPR activity


Jim, W5EST, presents, Ski Jump SNR: Interpreting XXP/XND-n6skm 630m D-Region Sunrise”:

 “Please recall the 3 days of XXP/XND-n6skm sunrise SNR sequences from a recent blog post illustrating last Nov. 5-7, 2016. http://njdtechnologies.net/072717/

Why was a post-SR bump peak in 630m SNR present?  630m confronts us with a real riddle. Tentatively, I’ll suggest a possibility how D-region absorption could cause this odd behavior.

See today’s illustration by first identifying the atmospheric regions as shown over Earth beneath. Then counterclockwise consider geometry of the D-region—how the Sun’s rays (yellow) penetrate the D-region (green) as the terminator moves westward.

As illustrated, D-region RF absorption westward of the terminator increases as soon as solar ionizing radiation reaches it.  On the sunward side of the terminator, only an initially moderate width W11 of D-region diminishes the ionizing radiation before it grazes the ozone layer (white) and reaches the pre-SR D-region. There, the ionizing radiation increasingly promotes absorption of more-eastward 630m RF (blue) in the D-Region. The 630m SNR downramp consequently begins its downslope from high nighttime SNR levels.

As the rising sun angle intersects the D-region sideways along a lengthier channel W12 , the D-region width W12temporarily absorbs solar ionizing radiation much more, on its way toward 630m RF path.  Less solar ionizing radiation reaching the RF path means less RF absorption. Less 630m RF absorption causes SNR to peak about the time two 630m stations A and B straddle the terminator.

I call the whole sunrise SNR downramp sequence “Ski Jump SNR.” This Ski Jump SNR has a SNR peak, or pause, midway down in its mostly down-sloping SNR sequence.  There, the rising Sun’s ionizing rays are encountering an increasingly lengthy, more absorptive D-region volume confronting the rays with width W12 as described above.

Before long, the  ionizing rays tilt higher and encounter a much-reduced width W13. The Sun’s rays now more fully ionize the D-region and increase still further its RF absorption as the Sun rises into morning.  The SNR rapidly declines from its temporary peak or bump up. Moreover, the westward half of the RF path increasingly becomes sunlit where it traverses the D-region. A D-region width W14 impedes the solar ionizing radiation, but width W14 rapidly shortens as the Sun’s rays tilt higher yet.  The 630m SNR falls to deep -20s dB SNR as daytime opens.

How can the post-SR bump peak in actually observed 630m SNR sequencing come as late as westward station sunrise or even later?  Doesn’t the illustration show it happening midway between stations A & B sunrises? Tough questions. I appeal to the idea that the D-region’s absorption has a time constant in the face of Sun ionization, a little like an RC circuit getting charged by a voltage source. That time constant delays and diminishes the prominence of the post-SR bump peak somewhat.

I lean away from saying that the post-SR bump is caused by D-region convection rolls or patches of different absorptions from disequilibrium turbulence in the D-region. That more unpredictable behavior may contribute of course.  But same SNR peaks were time-positioned about same each of three successive days last November on this AZ-CA path. I’d be more persuaded by some more predictable causative process, like the ray geometry of today’s illustration.

With the limited 630m SNR information I’m using and the variability of it, these ideas can only be offered tentatively. (Endnote*) I’d like to simulate the bump peak problem to avoid treacherously magnified diagrams. If you can point to a good reference addressing this topic, or just plain better 630m common sense, let us know for this blog.

I look forward to results from the upcoming 630m season in hopes we can get some deeper insight, or more nearly correct insight, into the workings of the 630m mystery band!  TU & GL.

*ENDNOTE:  Another mystery involves the XXP SR peak leading XND’s by 6-12 minutes.  How can that be, when XND is farther away by 61 km than XXP is from N6SKM?  Since XND is more eastward, shouldn’t a Sun-driven process have happened to XND first?
XXP lies somewhat a little closer to N6SKM and is situated WSW of XND.  So, one possibility imagines that the Sun’s rays extended into predawn darkness and ballooned the E-region downward more for the XND-n6skm path than for the more southwardly displaced XXP-n6skm path.   That way, the XND-n6skm path would intersect the D-region farther from XND and the terminator than does the XXP-n6skm path intersection from XXP.
Moreover, the XXP-n6skm path is a little shorter distance, making the launch angle for the RF more steeply inclined than for XND-n6skm.  The steeper launch angle will cause the RF to intersect the D-region closer to XXP and the terminator than XND-n6skm RF would.
With the November 5-7 terminator being within about ten degrees of exactly perpendicular to these paths, I’d suggest both these two factors account for XXP SNR curve leading the XND SNR curve at N6SKM:  1) orientation of downward ballooning E-region and 2) steeper launch angle of XXP.”

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