This session was characterized by really amazing band conditions and generally low noise levels, which are both atypical for early April when terrestrial storms are the norm. While preparing for my morning CW sked I was amazed at the number of WSPR stations being received, including WI2XBQ in Northern California and newcomer, WI2XFI. Here is what the waterfall looked like:
Having so much activity in April is unbelievable and its been a long time coming. I was recalling just days ago how in 2012 if we had three active stations at 474.2 kHz it was a good session. There were 87 MF WSPR stations providing reports at 0330z. Much of the advertising for 630-meters that has increased the fold comes from people “talking up” the band in public forums, club meetings, conventions and blogs. Steve, VE7SL, has made significant contributions spreading the good news about this band with blog reports like this one .
The persistence of the VK path this season is unprecedented and it seems to involve more than just additional active stations. Perhaps this is a preview to what is to come as we approach the solar minimum over the next few years. Conversely, the path to Japan has been more fickle recently. Why? VK3ELV experiences almost daily reports in Japan but why has the path become closed off at WH2XCR in Hawaii? A similar, yet admittedly shorter, lateral path to the Caribbean has been open during the same period.
Fritz Raab, W1FR, commented recently that his group has been working on a 600-meter band for 12 years now with almost 200,000 hours of interference-free transmissions. The current crop of ambitious independent Part-5 operators continue to add to the existing body of knowledge and “push the envelope” to lengths that have never been observed before, dispelling myths and opinions held by many that these bands are worthless. The same thing was said about HF in the early 20th century. Fortunately many of the non-believers are coming around and beginning to see that maybe there really is something to all of this MF and LF business. And, of course, seeing operators successfully use simple stations goes a long way in furthering what we do. It gives hope to the guy who might be in a restricted neighborhood or zero lot line property.
Geomagnetic numbers have returned, temporarily, to quiet levels. The Kp is near 1, Bz is at 0 nT, and solar wind velocities are below 400 km/s. Solarham reports that all of this is about to change again. Cue the roller coaster once again.
Phil, VE3CIQ, reports good propagation and notes that he decoded eight WSPR stations and was decoded by 23 unique stations.
Mike, WA3TTS, sent along these statistics for the session from his station in Pittsburgh:
Larry, W7IUV / WH2XGP, says it was a good night, decoding twelve WSPR stations and being decoded by forty unique stations, including three VK stations for 27 total spots:
Ken, K5DNL / WG2XXM, reports that he decoded twelve WSPR stations and was by decoded 42 unique stations including seven VE stations.
John, WA3ETD / WG2XKA, was transmitting full-time once again and provides the follow comments:
Mark, WA9ETW, reports eleven WSPR stations decoded at his station prior to shut down near 0530z, including good S/N from stations in the western portions of North America.
Neil, W0YSE/7 / WG2XSV, is back to normal power after acquiring an amp from Ward, K7PO / WH2XXP, and issues this report:
John, VE7BDQ, received reports from 28 unique WSPR stations between 0430z and 0900z. David, VK2DDI, reported that John was decoded at his station at 0930z.
Regional and continental WSPR breakdowns follow:
There were no reports from the trans-Atlantic or trans-African path. UA0SNV was present from Asiatic Russia but no WSPR reports were found in the WSPRnet database.
Eden, ZF1EJ, and Roger, ZF1RC, provided reports for stations across North America. Eden reports WH2XCR in Hawaii as well.
In Alaska, Laurence, KL7L / WE2XPQ, experienced a typical night with reports along with west coast of North America in addition to WH2XCR on KH6.
In Hawaii, Merv, K9FD/KH6 / WH2XCR, also experienced a typical session, with two-way reports at VK4YB, receptions of VK3ELV, and reports by VK2DDI, VK2XGJ, and main stations on the mainland of North America. John, VK2XGJ, sent along a screen shot of an early report for Merv shortly after sunset of 0747z in VK, presented below:
In Australia, Phil, VK3ELV, and Roger, VK4YB, both received reports from WH2XCR. Roger experienced two-way reports with WH2XCR. Phil received numerous additional reports from stations in Japan:
Jim, W5EST, provides an analysis of the recent open paths to VK in this discussion, entitled, “NORTH AMERICA-AUSTRALIA 630M SEASON& APRIL 3 XXM SPOTLIGHT”:
“March 17, this blog asked how long the 630m season will last for transatlantic WSPR spots. May 24, perhaps? Last year, John W1TAG/1 reported 9 spots of Stefan DK7FC and one from Jan PA3ABK/2 into John’s WSPR RX that night.
And what about the N. America-VK mini-season that brackets March equinox? The latest N.Am.-VK equinox mini-season started Feb. 9. This blog (2/22) noted the annual asymmetry of storm seasons in the N. & S. Hemispheres in spite of the annual symmetry of the sun’s arc during these equinox mini-seasons. What an auspicious time for testing and improving VK/ZL/W/VE long path equipment and antennas! How long beyond April 20 (a month post-equinox) can we hope for? Only persistent 630m operators can tell us.
Phil VK3ELV 5w, John VK2XGJ, David VK2DDI, and Roger VK4YB have been blazing the trail down-under in 2016. Laurence WE2XGP, Larry WH2XGP 10w, Ron WH2XND 20w, Steve VE7SL, and Ken WG2XXM 5w, round out the current list from the N. America path ends.
Only 6 spots for the mini-season had occurred by March 2. After a 3-week gap, spots resumed March 24 with considerable vigor since then. (See the spots, and please tell if I’ve missed any spots for these paths.)
On April 1 and April 3 some spotlighting seems likely, side-noted list appended. April 1 saw nine XGP Sydney-only spots inserted timewise between XXM Brisbane-only spot groups.
On April 3, 64 minutes of XXM-Sydney overlapped 60 minutes of XXM-Sydney: 14 minutes of overlap. By contrast meanwhile, XGP-Sydney/Brisbane spots mingled together in roughly the same overall April 3 session. Given the different behaviors, the propagation interpretations for XXM and XGP probably also differ.
Regarding XXM April 3, I interpret that particular spotlight as moving from Sydney 710km northward to Brisbane between reception time-centers 1006z Sydney and 1054z Brisbane, in 0.8 hr. XXM’s spotlight average south-north velocity April 3 was 888km/hr (247m/sec). That’s roughly the speed of a sound wave* in the ionosphere, considerably greater than ionospheric drift velocities.** But hang on, wait and see why I nevertheless conclude ionospheric drift!
The spotlight likely kept its N/S width constant throughout, because the reception interval near Sydney was virtually same as the interval near Brisbane. The spotlight edges probably moved at same rate as the spotlight center as well. I conclude the XXM April 3 spotlight was 918km across, south-north, 888km/hr x (48min+14min)/60min-per-hr). How to interpret?
I suggest that in the N. Hemisphere, XXM’s sky wave signal reflected from a drifting curved ionospheric contour and descended down to a surface footprint twice as wide on that early hop. Then subsequent multiple hops multiplied the footprint width geometrically to achieve the 918km spotlight width in Australia while multiplying the velocity of the spotlight center like a pantograph https://en.wikipedia.org/wiki/Pantograph .
To get the ultimate wide 918km spotlight width in Australia, I appeal to multihop and pantograph multiplication of early width. That means I have to accept pantograph velocity multiplication originating in an early hop along with it. If so, the velocity of the original contour has to be a fraction of the ultimate 247m/sec speed. And that constrains the interpretation to involve ionospheric drift instead of an ionospheric acoustic wave traveling at speed of sound.
I recognize that XXM SNR peaking as strong as -22dB into VK2DDI makes a multihop interpretation a tough sell. Could some duct or chordal hop interpretation deliver the same spotlight width? If so, write in and carefully explain a suggested duct or chordal hop geometry with a diagram in this blog to account for XXM’s spotlight velocity and width.
Thanks and GL with the rest of the long-path season!
* Harris,T., & M. Cervera (undated) Investigations into Small-Scale Disturbances in the Ionosphere Using SpICE. “MSTIDs typically have periods in the range of 10 to 60 minutes, with horizontal wavelengths of 100 to 300 km and horizontal speeds from 100 to 250 ms-1.” http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=3&ved=0ahUKEwianMjmyPXLAhVK7CYKHSgpBW4QFggmMAI&url=http%3A%2F%2Fwww.ursi.org%2Fproceedings%2Fprocga11%2Fursi%2FG07-1.pdf&usg=AFQjCNHTot79cvv9_ZPjd4LipzEx8wiFxA&bvm=bv.118443451,d.eWE
Harris, T. J., M. A. Cervera, and D. H. Meehan (2012), SpICE: A program to study small-scale disturbances in the ionosphere, J. Geophys. Res., 117, A06321. “Medium-scale TIDs (MSTID)…travel in many directions and have a more varied set of sources, from tropospheric jet streams, to atmospheric gravity waves (AGW), to the solar terminator. MSTIDs typically have periods in the range of 10-60 minute periods, horizontal wavelengths 100-300 km and horizontal speeds 100-250 m/s. [JH: This means AGW frequency is 0.26-1.7 milliHertz, deep subsonic. Hardware was located near Adelaide, Australia. The paper is partially obscured unless you pay a fee.]
**Kouba, D., et al. (19 Feb 2008). Ionospheric drift measurements: Skymap points selection. Radio Science 43(1) http://onlinelibrary.wiley.com/doi/10.1029/2007RS003633/pdf . [JH: less than ~100m/sec drift above Prague, Czech Rep.]”
Additions, corrections, clarifications, etc? Send me a message on the Contact page or directly to KB5NJD <at> gmail dot (com)!