It was a successful session on the trans-Pacific path for Roger, VK4YB. Numerous reports from VE7SL, VA7MM, VE7BDQ, WI2XBQ and two-way reports with WH2XGP characterized the pre-dawn hours in western North America. A combination of Roger’s antenna and location are major influences on his success. Located on the coast of north eastern Australia, Roger’s antenna is reported to be a unique vertical in a 100-foot tall gum rubber tree, fed at the top with a single radial that is end fire to KH6 and top loading near ground level. Power levels are reported to be 50-watts TPO.
Curiously, geomagnetic conditions were elevated to storm levels with a South-pointing Bz and solar wind velocities in excess of 500 km/s. The timing of these geomagnetic events may have provided a necessary boost for these trans-Pacific reports as signals from VK seek to move away from regions of high electron density. Similarly these events likely resulted in poor conditions at mid and higher latitudes.
John, WA3ETD / WG2XKA, operated QRO for the session and provided this report from Vermont:
Neil, W0YSE/7 / WG2XSV, reported nine stations decoding his signal in Vancouver, Washington on what was clearly a challenging evening in western North America.
My station QRT’ed at 0100z due to approaching storms. My activity over the coming ten days is uncertain due to numerous weather systems that will be impacting the area. I will operate as much as I safely can.
WSPR activity worldwide has been typical compared to recent sessions with 72 MF WSPR stations observed at 0215z. W3LR was observed as a new receiving station during this session. Welcome aboard!
Regional and continental WSPR breakdowns follow:
There were no WSPR reports from the trans-Atlantic or trans-African path during this session. UA0SNV was present during the session but no reports were found in the WSPRnet database.
Eden, ZF1EJ, reported WG2XXM and WH2XZO during this session. Presumably gulf noise was more extensive than the previous session.
Laurence, KL7L / WE2XPQ, was a victim of the geomagnetic storm conditions, limiting his reach to stations in western North America and Hawaii.
Merv, K9FD/KH6 / WH2XCR, received numerous reports from Australia including continued two-way reports with VK3ELV and VK4YB. The path to JA continues to be cut off and Merv’s reports to and from mainland US and Canada were limited to the West, a very rare occurrence.
Additional reports from Australia include two-way reports for VK3ELV and VK4YB with WH2XCR. VK3ELV received late reports from the previous session at JH3XCU.
The path to Japan from Hawaii has been mysterious and Jim, W5EST, examines one facet of the path in this discussion entitled, “TIDAL ACCOUNT OF 630M XCR-JA PATH?”:
“A tidal interpretation or account of the 630m XCR-JA decodes this season is speculative and unfamiliar. I feel forced to consider ionospheric tides only because of the fortnightly periodicity of the spikes in the numbers of XCR-JA decodes. Tides in the ocean are not an unfamiliar concept. Indeed, the first endnote* tells us the literature does recognize tides in the atmosphere generally, and that includes the ionosphere.
I’ve superimposed a freehand envelope on the window-filtered spiky graph of numbers of decodes for the 630m WH2XCR-JA path this season. The envelope responds to fall-winter-spring night lengths and apparently modulates a pulse train of two-week fortnightly neap tides. Northern Hemisphere night length reaches a maximum at winter solstice, of course. The peak of this envelope is delayed a couple of weeks from winter solstice.
Regarding the fortnightly pulse train of XCR-JA decodes, the dates of lunar phases this 630m season suggests the pulse train is delayed about three days from lunar first and third quarters. These quarters are the times when the gravities of the sun and the moon minimize ocean tides. Tides have a twice-daily pattern forced not only by gravity but also by solar heating. The fortnightly cycle of rise and fall of the strength of that twice-daily pattern is the focus here.
The thermally and physically massive earth-ocean-atmosphere is a generally spherical system in which oscillations or physical standing waves driven by thermal and gravitational forcing could conceivably delay the time of minimum tides in the ionosphere compared to the time of those in the ocean below. When ionospheric tides are minimum, tidal disturbance of the reflective contours of the ionosphere would be minimum. So 630m waves would most readily reach Japan from XCR in Hawaii. That’s the idea anyhow.
Truth in advertising: The data does have some departures from the assumed pattern. Three lunar first-quarter dates 10/20, 11/19, 3/16 lack corresponding peaks in the graph. Will the next 1st quarter point April 15-April 17 also miss for XCR-JA? On top of all that, how could one possibly reconcile monthly TA peaks with fortnightly XCR-JA? TA transits more northerly Atlantic latitudes than XCR-JA but is that a meaningful difference.
630m exquisitely keeps its secrets! More tomorrow!
DATE TABLE OF LUNAR PHASES 2015-2016 SEASON
Full moon: 8/29 9/28 10/27 11/25 12/25 1/24 2/22 3/23 4/22 5/21
3rd quarter: 9/5 10/4 11/3 12/3 1/02 2/01 3/01 3/31 4/30 5/29
XCR-JA peaks 10/8 11/6 12/4* 1/04 2/04 3/04 3/27,30
2015-16 TA peaks 10/5 11/1 12/4 1/01,10, 20,28 3/06 3/27,30
New Moon: 9/13 10/13 11/11 12/11 1/10 2/08 3/09 4/07 5/06 6/05
1st qtr.: 9/21 10/20 11/19 12/18 1/16 2/15 3/16 4/14 5/13 6/12
XCR-JA peaks 12/21 1/21 2/16
* These references are only partially available on web but should be library-accessible:
Pancheva, D., & Mukhtarov, P. (2011) Global Response of the Ionosphere to Atmospheric Tides Forced from Below: Recent Progress Based on Satellite Measurements. Space. Sci. Rev. http://link.springer.com/article/10.1007%2Fs11214-011-9837-1#page-2
Iwasaki, S., Isobe, A., & Miyao, Y. (2015). Fortnightly atmospheric tides forced by spring and neap tides in coastal waters. http://www.nature.com/articles/srep10167
Chapman, S., & Lindzen, R.S. (1970) Tides: Thermal and Gravitational. Dordrecht, Holland: D. Reidel Publ. Co., pp. 56, 66-91, 151, 166.
**Day-average of two-peak doublet of peak XCR-JA decode numbers Nov. 29 and Dec. 8.”
Additions, corrections, clarifications, etc? Send me a message on the Contact page or directly to KB5NJD <at> gmail dot (com)!