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CQ 474.5 kHz CW

Great domestic propagation and band conditions including early transcontinental between WH2XGP and WA3TTS and WG2XSV and ZF1EJ; Another big night for JA, VK, ZL, and stations in western North America; MF CW QSO party in Europe this weekend!

– Posted in: 630 Meter Daily Reports, 630 Meters

The band was solid around North America and improved drastically as the persistent storm system in the southeastern US finally ran out of energy and moved out to sea.  The great circle path to Europe, which is generally to the North for many locations in North America, never opened in spite of very quiet geomagnetic conditions.  It certainly was not due to a lack of activity in Europe.  The trans-Pacific path between North America and Oceania was active, however, and even WE2XPQ was in on the action again in a seemingly big way so the high latitudes appear to be in pretty good shape.

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11-hour North American lightning summary

 

Geomagnetic conditions are persistently quiet once again with a Bz that has been variable but generally at unity.  Solar wind velocities are low, averaging 360 km/s.  Protons are also elevated to moderate levels.  DST values are nominal.

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Neil, W0YSE/7 / WG2XSV, reported early transcontinental decodes at ZF1EJ with a -19 dB S/N at 0534z.  Neil also reported a number of early eastern stations as well, including KU4XR:

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WG2XSV early evening WSPR activity

 

It didn’t end there and Neil experienced a strong night that is clearly the result of station improvements.  He provided these additional comments, statistics, and details:

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WG2XSV 24-hour WSPR activity

 

Doug, K4LY / WH2XZO, reports that QRN abated overnight, allowing him to decode eight WSPR stations and was decoded by 44 unique stations.  Doug experienced a record for his station of 25 decodes in a single WSPR transmit cycle.

Ken, K5DNL / WG2XXM, reports that he was decoded by 57 unique stations including WE2XPQ.

Rick, W7RNB / WI2XJQ, reports that he decoded eight WSPR stations and was decoded by 37 unique stations including ZF1EJ, W5THT (WD2XSH/6), and WI2XBV, the latter two receiving Rick for the first time.  Rick’s unique report details can be viewed here.

Toby, VE7CNF, reports, “Last night WSPR 630m I decoded10, decoded by 42 at reduced power ~2.5W EIRP due to a power supply failure.”

Trans-Pacific WSPR report details for this session are aggregated here.

Ward, K7PO / WH2XXP, received reports from 67 unique stations, including  7L1RLL4, JA1NQI-2, JA3TVF, JE1JDL, JH1INM, JH3XCU, VK2XGJ, VK4YB, ZL2BCG, and ZL2IK.

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WH2XXP session WSPR activity

 

Larry, W7IUV / WH2XGP, received reports from 55 unique stations including JA1NQI-2, JH1INM, VK4YB, and ZL2BCG.  As W7IUV, Larry decoded ZL2BCG, and VK4YB.

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WH2XGP session WSPR activity

 

Roger, VK4YB, provided reports for WH2XGP, WH2XXP, ZL2BCG, WE2XPQ, and WH2XCR, and received reports from fourteen stations, including JA3TVF, JH1INM, VA7JX, VK7TW, W7IUV, WE2XPQ, WH2XCR, ZL2BCG, and ZL2IK.

ZL2BCG received reports from eight unique stations, including VA7JX, VK7TW, W7IUV, WE2XPQ, WH2XCR, and ZL2IK.

Mike, WA3TTS, took advantage of quieter conditions and offered this report:

“…Wet local conditions seemed to improve the local noise situation overnight, despite the more distant skywave QRN.”

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WG2XSV decodes, which is much higher than normal reception here… -22 to -31

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This weekend marks the next installment of the European MF QSO party, this time on CW!  Its a busy time of year but please support these activity nights by making and reporting a few QSO’s!

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I opted to start WSPR mid-afternoon as I had afternoon appointments that would prevent me from being available for evening CW or to even start WSPR by 0100z.  The band yielded no daytime reports, the first report being just prior to local sunset.  Reports were generally strong once dark but no enhancements were observed at sunset.  I suspect much of this was the result of noise in the southeastern US.  The band produced persistent CW and even phone levels  to the Midwest with alternating periods of strong propagation in the East and West.  The East yielded more consistent domestic results.  It was also nice to receive reports from WE2XPQ.  Morning CW yielded no additional QSO’s but Eden, ZF1EJ, reported that I was RST 559 at 1113z and consistently RST 539 through an abridged CW session that ended at 1150z today.  WSPR transmission reports can be viewed here and WSPR reception reports can be viewed here.

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WG2XIQ 24-hour WSPR activity

 

Regional and continental WSPR breakdowns follow:

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North American 24-hour WSPR activity

 

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South American 24-hour WSPR activity

 

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European 24-hour WSPR activity

 

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African 24-hour WSPR activity

 

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Central / Asiatic Russian 24-hour WSPR activity

 

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Japanese 24-hour WSPR activity

 

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Australian and New Zealand 24-hour WSPR activity

 

Eden, ZF1EJ, decoded fifteen unique stations for a new record at his station including. VE3CIQ, VE3EFF, VE7CNF, WD2XSH/15, WG2XIQ, WG2XSV, WG2XXM, WH2XCR, WH2XGP, WH2XNG, WH2XXP, WH2XZO, WI2XJQ.  Detail reports for those stations can be viewed here.

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ZF1EJ 24-hour WSPR activity

 

Laurence, KL7L / WE2XPQ, experienced another night of significant reports with good coverage in Japan as well as two-way reports with VK4YB and WH2XCR.  Laurence also provided reports for ZL2BCG.  His DX report details for this session can be viewed here.

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WE2XPQ 24-hour WSPR activity

 

Merv, K9FD/KH6 / WH2XCR, appears to have had more reports from the eastern portions of North America than the West during this session (eyeballed, not counted!).  JA coverage was very good once again and Merv shared two-way reports with VK4YB, ZL2BCG, and WE2XPQ.  Merv’s DX report details can be viewed here.

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WH2XCR 24-hour WSPR activity

 

Jim, W5EST, presents, “630M SUNRISE, 630M SUNSET: PART III”:

“Arizona’s WH2XXP registered a range of 40 dB WSPR SNRs at N6SKM’s receiver November 30. See first illustration.  At bottom, time flows from right to left. SNR steadily rises from -30 dB during the pre-sunset (Pre-SS) regime and reaches +8 dB about 1.5 hours later. A 25 minute intermediate sunset regime is defined by the sunset times at XXP and N6SKM.

For about 12 hours from 0200-1400z, SNR was mostly confined to a range between 3-10 dB WSPR SNR.  Most of the nighttime hours are accordingly omitted from the illustration.

Respective sunrises 1418z & 1503z at XXP and N6SKM delimit a 45 minute intermediate sunrise regime, as shown at top. During that interval SNR rapidly diminishes about 25 dB, shown split between two stairsteps marked 1424z and 1448z.  By about an hour afterwards, SNR has lost roughly another 10 dB.

The sun’s very low angle prior to AZ sunset probably accounts for the late afternoon SNR increase.  Solar flux density on a given part of the ionosphere can be expected to vary as the trigonometric sine of solar elevation above the horizon sin ϕ (phi).  With less radiation to induce absorption, the SNR rises. After sunset, solar radiation is lost and the absorption dissipates, exponentially I suspect, with a time constant represented by the slope of a line through the SNRs. (SNR dB is logarithmic and straightens out a decaying exponential of signal absorption.)

WSJT-X Echo mode could probably reveal a great many more interesting variations in SNR overnight at its three second time scale than WSPR does over two minutes per point shown.

Why was the interval between sunsets only 25 minutes when the interval between sunrises was 45 minutes? That’s because the sunset heading 244° is very different from the sunrise heading 116° this time of year approaching winter solstice on this northern hemisphere NW path. The 45 minutes between sunrises nicely spreads out the SNR behavior and shows that pair of distinct SNR stairsteps. I’ll say more about them in a minute.

The Post-SR regime includes a final 10-15 dB downward thump in SNR. As the sun angle rises higher above the horizon, solar flux density increases absorption to daytime levels.

Turning to today’s second illustration (not drawn to scale), the sunrise SNR stairstep timings suggest that a wave front of rising absorption is geographically progressing along the signal path. The effect of increased absorption on SNR appears to be concentrated two main places deduced from the stairstep timings. First, about 1/7 of the way (1424-1418z)/(45min) the first stairstep applies about 15 dB loss.  Later, about 2/3 of the way (1448-1418z)/(45min) the second stairstep applies perhaps 12 dB loss.

One can do some geometry on a properly scaled drawing to extend a line skyward from the TX through the absorbing layer at 1/7 the way along a great circle arc between TX and RX. Another line descends to RX and goes through the absorbing layer at 2/3 the way. At the very rough level of accuracy here, it’s possible that the asymmetry is simply insignificant. However, the asymmetry seems rather marked and, if one were confident of it, would suggest some tilt in a reflecting surface at altitude.

The place where the lines intersect is presumably the point of reflection. That way one can roughly estimate the ratio of the altitude of reflection to the altitude of absorption. When did an estimate, I got a value a little over 2.  That’s consistent with the ratio of altitudes E-layer to D-layer.

No sunrise enhancement or bumps before or after sunset or sunrise are obvious from this WH2XXP-n6skm one-night set of WSPR2 SNRs.  Perhaps you have some dramatic 630m experiences in this regard.  Let us know, and we will be happy to blog them!”

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