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The geomagnetic field is angry as a G2 storm is underway follow recent strong flaring; W5EST presents ”Do Pre-SR E-Region Width and Bulge Vary with Latitude Near Terminator?”

– Posted in: 630 Meter Daily Reports, 630 Meters

The details for July 17, 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.

Noise conditions were more of the same and primarily sourced from airmass thunderstorms that flared up during the afternoon and evening.  As the night progressed, many storms decreased in intensity and by morning noise levels had decreased to moderately high levels.

11-hour North American lightning summary


Geomagnetic conditions reached G2 storm levels for several reporting periods as the CME that originated with recent flaring impacted the Earth’s magnetic field.  Conditions continue at unsettled levels but for the moment the worst seems over.  The Bz is currently pointing to the North after reports near -20 nT just 24-hours ago and -40 nT on impact a few hours earlier than that.  Solar wind velocities are averaging near 500 km/s with a few excursions near 550 km/s.  Generally, solar wind velocities have remained below 500 km/s this morning.  DST values have been profoundly impacted, including the Australian measurement that is as low as I have seen it in a very long time.  While the previous session suggested some enhancements occurred at onset of the geomagnetic event, that doesn’t appear to be the case during this session.




Al, K2BLA / WI2XBV, reported moderate noise in Florida.  He provided reports for four WSPR stations.

Neil, W0YSE/7 / WG2XSV, reported that he decoded five WSPR stations including WH2XCR.  He received reports from twelve unique stations, all located in the western portions of North America.

Roger, VE7VV, reported that the path to KH6 was good as his “23dbm EIRP was decoded by XCR last nite at 0730, just before my WSJTx went down…”  Its possible that the path continued to show promise after the software crashed.

Joe, WA9CGZ, reported that “swl/k9 and myself not RXing due to strong interference from local AM broadcast stations strong noise sidebands may be due to lightning hit at station and they maybe on backup TX.”  He is currently trying to contact the station to report the problem and has filed a complaint on the FCC’s website.

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

Larry, W7IUV / WH2XGP, provided reports for four WSPR stations and he received reports from nineteen unique stations including ZL2AFP.  As W7IUV, Larry provided reports for five WSPR stations.

WH2XGP 24-hour WSPR activity


I operated WSPR briefly during the evening but once the overnight weather forecast was reported, which included a relatively high storm potential, I QRTed and secured the station again.  Prior to that I was in listening mode and was only hearing two stations, WD2XSH/15 and WH2XXC.  It was much too early for quality openings to develop.

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 and he received reports from seven unique stations.  He shared two-way reports with WH2XCR, which has been rare in recent months.

ZF1EJ 24-hour WSPR activity


Warwick, E51WL, provided reports for six WSPR stations.  Report details can be viewed here. (note that these reports stop at 1515z and additional session reports roll-over to the next reporting day).

E51WL 24-hour WSPR activity


Laurence, KL7L / WE2XPQ, provided reports for one stations, WH2XCR.  Laurence indicates that he has a rebuild project in process and I expect there to be more details to follow shortly.

WE2XPQ 24-hour WSPR activity


Merv, K9FD/KH6 / WH2XCR, shared two-way reports with VK4YB and ZF1EJ and he received reports from E51WL, WE2XPQ, VK2XGJ, and ZL2AFP.  Merv’s DX report details can be viewed here.

WH2XCR 24-hour WSPR activity


Jim, W5EST, presents, “Do Pre-SR E-Region Width and Bulge Vary with Latitude Near Terminator?“:

“Today’s discussion speculates about possible differences especially around sunrise SR regarding the shape of the E-region as between high latitudes and mid-latitudes.  I imagine 630m pre-SR enhancements arising from additional RF signal reflection off a slanting, bulging E-region that has expands in response to the sun’s ionizing radiation.   The geographic location and timing of 630m pre-SR enhancements would, in my view, depend on the 3D shape of the E-region contours that your RF signal encounters on the way from its originating TX station to destination RX station.

The accompanying illustration superimposes on a WSPR database map my imperfect artistry applying darker, denser shades over N. America to represent progressively higher, thinner parts of the E-region farther from the terminator.  The lower, thicker bulging parts of the E-region are the lighter unpainted areas not far south or SW from the terminator around 1030z, July 13 (Endnote 1*).

The high latitude parts of the E-region in my imagination bulge down to lower altitudes for longer distances wider away south or SW from the high latitude terminator than at lower latitudes.  Why? One, because the Earth rotates at slower linear velocity, and so presumably does its E-region, at high latitudes. Two, because this July time of year the terminator lies much more nearly east-west at the high latitudes. That means the sun’s ionizing radiation spends more time energizing a given geographic portion of the E-region at the high latitudes.

That more additional time allows pressure in the E-region to bulge the E-region farther downward in altitude and farther away south or SW from the terminator than it could at lower latitudes. At lower altitudes the higher, thinner E-region is much more rapidly moving eastward from night into sunlit morning and cannot bulge down as far, nor extend that bulge as far into the pre-SR dimness or darkness.  The illustration shows this.

From higher to lower latitudes in the illustration, the higher altitude, thinner parts of the E-region more widely diverge from the position of the terminator at higher latitudes than lower latitudes. (See the dashed lines more closely approaching each other at the lower latitudes.)

Moreover, the way I imagine it, the higher latitude E-region slants more steeply at distances farther from the terminator than it does at lower latitudes.  That provides more opportunities for lateral skew to support pre-SR enhancements.

Plasma transport in the E-region at high latitudes is ignored here, and it may quite importantly affect things. For some moderately pertinent references, see Endnote 2.**

Do you have some good, on-point scientific references that discuss this subject of E-region shape near the terminator at various latitudes?  Can you provide more informed 630m radio experience?  Send your comments and contributions to me at mrsocion@aol.com so we can blog them!  TU & GL.”

* For a world map view of the July terminator see: http://dx.qsl.net/propagation/ (scroll to middle for mid-July darkened earth).  See also the spherical Earth with June 21 terminator at upper right in this site: https://en.wikipedia.org/wiki/Terminator_(solar)#/media/File:Seasonearth.png
** Polar plasma transport at 180km and above: https://books.google.com/books?id=8YwHCAAAQBAJ&pg=PA290&lpg=PA290&dq=polar+terminator+ionosphere&source=bl&ots=d48rJeV0eP&sig=z7AuyQVu7o296KNe780YAXqk1Dw&hl=en&sa=X&ved=0ahUKEwiQ8v3KrI7VAhVq5oMKHUsvAYMQ6AEIPjAI#v=onepage&q=polar%20terminator%20ionosphere&f=false
Relations of F-layer and E-layer: http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=0ahUKEwi3tfW9qY7VAhXLsFQKHdonBDkQFggiMAA&url=http%3A%2F%2Fwww.ann-geophys.net%2F27%2F107%2F2009%2Fangeo-27-107-2009.pdf&usg=AFQjCNHMf4MmqpNJbZFthTpe7fHidmPmnw


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