It was a low noise night here in Texas although many areas of North America are experiencing precipitation noise due to Winter storm conditions that are moving across parts of the country. Ken, SWL/EN61, located in Indiana, indicates that precipitation static is far worse than thunderstorm QRN due to its ability to consistently raise the noise floor. North America was generally free of thunderstorms overnight and resulted in easy listening here:
Geomagnetic activity has subsided during the session with the Bz pushing solidly to the North although solar wind velocities continue to peak above 500 km/s. DST values have been variable but have improved significantly during this session, even reaching unity.
Trans-African openings continue as EA5DOM was reported by FR5ZX. As mentioned last week, the lack of variety in received stations at FR5ZX is interesting. Hopefully as we progress into Winter the number of stations received by Michel will increase as it did last year. Report details for this crossing can be viewed here.
Trans-Atlantic openings continue to become more numerous as N1BUG and VE1VDM report G8HUH. VE1HF and WD2XSH/17 both reported EA5DOM with WD2XSH/17 being the big winner during this session with reports from G8HUH, DL-SWL, G0LUJ-1, G0LUJ/2, G3XKR, G8LCO, and PA0RDT. WG2XJM also reported EA5DOM and was reported by F1AFJ and WG2XXM was reported by both receivers at F1AFJ. Report details for these stations can be viewed here.
Doug, XE3/K4LY, was listening from Cancun during this session but local noise and a lack of Internet complicated his ability to receive and report from his hotel room. He spent some time listening during the evening from downtown Cancun where he had Internet access but was not successful in decoding any WSPR stations.
Neil, W0YSE/7 / WG2XSV, reports, “…I heard XJM as my eastern RX dx, and KU4XR was my eastern TX dx this session. NE4RD in Billings MT, whom I have not seen in a long time, was present in my TX list. Merv/XCR in HI of course is seeing me every night which is always reassuring.”
Rick, W7RNB / WI2XJQ, reported that he decoded seven WSPR stations and was decoded by 22 unique stations including first time reports from NE4RD. Rick indicates that activity was down a bit. His unique report details for this session can be viewed here.
Trans-Pacific report details for this session (excluding KH6 and KL7) are aggregated here.
Ken, K5DNL / WG2XXM reported that he was decoded by 59 unique stations, including VK4YB and F1AFJ. Ken also reports that he received 52 WSPR decodes from WH2XCR at a distance of 6007km, best report at +1 dB S/N.
Ward, K7PO / WH2XXP, received reports from 56 unique stations including VK4YB, VK2XGJ and ZL2BCG.
Roger, VK4YB, reported that while noise was low, early propagation was showing signs of being very short. Fortunately openings turned around as the session progressed with Roger receiving reports from JA1NQI-2 as well as W7IUV and N6RY. Roger provided reports for WH2XXP and WG2XXM.
Larry, W7IUV / WH2XGP, reported that he is back on the air for the moment as the antenna ice has sublimated. It could return at any time, however. Larry reports that he decoded VK4YB fourteen times as W7IUV, best at -17 dB S/N and down from yesterday.
Yesterday’s daytime WSPR session was interrupted by high winds and I decided it was safer to QRT until conditions calmed down. Evening CW was generally uneventful and the band was quiet so any present signals would have likely been heard. In fact a mystery signal was heard at the beginning of my CW activity. It was located just above 475 and sounds like a 3 second burst of carrier, repeated every few seconds. When I began CQing, it was like the signal moved down to where I was at 474.5. I called it out and it stopped, as if someone were listening and realize that they had been detected. I don’t know if someone was testing or playing around but I do believe that it may have been intentional and man-made and not an artifact of an electronic device in the neighborhood. The signal was very light on my remote grabber.
Evening and overnight WSPR resulted in good coverage across North America with plenty of CW level reports, particularly from the Midwest and eastern US. The band seemed to be fairly stable unlike previous session that exhibited significant fading. For many the biggest enemy was precipitation static. Morning CW netted a report from Eden, ZF1EJ, who indicated at 1118z that my signal was RST 559. My WSPR transmission report details can be viewed here and my WSPR reception report details can be viewed here.
107 MF WSPR stations were observed at 0330z on the WSPRnet activity page. VE2FXL was observed as a new receiving station during this session. I need to report a correction: over the last year we have had a number of stations reporting from the Northern US, specifically Wisconsin and Minnesota. I have on many occasions confused stations in Minnesota as being located in Wisconsin and visa versa. Part of it is call sign confusion and part of it was not realizing where the boundaries were located for each state. Most recently I have indicated that WB0VAK was located in Wisconsin while he is, in fact, located in Minnesota. He is not too far from the border but I no doubt misreported his location. Last year I put WD0AKX in Minnesota. My apologies for this misrepresentation.
Regional and continental WSPR breakdowns follow:
Eden, ZF1EJ, provided reports for VE3CIQ, VE3EFF, WD2XSH/15, WD2XSH/17, WG2XIQ, WG2XJM, WG2XXM, WH2XCR, and WH2XXP. Report details for these stations can be viewed here.
Laurence, KL7L / WE2XPQ, reports that high losses continue on most paths in Alaska overnight.
Merv, K9FD/KH6 / WH2XCR, reported VK4YB and ZL2BCG in Oceania and WG2XJM in western Pennsylvania. He also received reports from ZF1EJ, WE2XPQ, 7L1RLL4, JA1NQI-2, JA3TVF, JE1JDL, JH3XCU, ZL2BCG, VK4YB, and VK2XGJ. Merv’s performance has largely been unaffected through this most recent geomagnetic event but his storm QRN continues. His DX report details for this session can be viewed here.
Jim, W5EST, presents, “BATMAN CHART” FOR POST-SR / PRE-SR DURATIONS VS. LATITUDE”:
“630m experience tells us the propagation hours around sunrise and sunset can be particularly interesting and important because of their SNR volatility. In the geographic latitudes roughly between VK7/ZL 40°S and JA/W9/W2/EA/SV 40°N, the moderate durations of the associated propagation regimes vary not much but nevertheless noticeably throughout the year. As the latitudes get more extreme, however, the durations lengthen considerably and can seasonally vary in duration by as much as two-to-one. Familiar events to high latitude 630m operators can be surprising to mid/low-latitude denizens, me included!
Today’s upper half-illustration shows the duration hours of the equal post-sunrise/pre-sunset 630m regimes* at various latitudes and times of year, with winter solstice in the middle. For instance, the solid green arrow from the dotted zero reference line up to the green curve for latitude 60° shows approximately 2.7 hours duration of post-SR at winter solstice. Latitude 60°N roughly applies to Anchorage, Alaska, and middle-Scandinavia. You can probably guess why I call this a Batman chart after the fictional character!
Currently, all the existing 630m amateur and US experimental stations are located between the Arctic Circle 66.5°N and the Antarctic Circle 66.5°S. I limit today’s discussion of 630m regimes around SR and SS to N/S latitudes up to about 60°. The same curves apply to latitudes in the southern hemisphere provided you read the curves against months stated in blue, which are offset by six months from months legended in black.
In the lower half-illustration below the dotted zero reference line, see curves for the duration hours of the pre-sunrise/post-sunset 630m regimes** at the various latitudes and times of year. The dashed green arrow from the dotted zero reference line down to the green curve for latitude 60° shows approximately 2.1 hours duration of pre-SR at winter solstice.
The lower half-illustration resembles the upper half-illustration turned upside down and displaced sideways six months. All the curves are color-coded, and a few amateur prefixes are correspondingly color-coded to relate various latitudes to their amateur radio geography. The last endnote***gives a spreadsheet formula.
Especially at this time of the 630m year in N. hemisphere, the sun is low in the sky for an extended period of time after sunrise and prior to sunset. Your reception experience probably already has demonstrated how the rough boundary line sunrise puts between reception and non-reception becomes even more blurred and vague in the weeks around winter solstice.
Ward WH2XXP achieved a decode at LA2XPA 8061 km Dec. 4 – about an hour after Norway sunrise. This decode was still only one third of the way through Rolf’s post-SR propagation regime! http://njdtechnologies.net/120416/
Returning to today’s illustration, I wondered why the “Batman ears” point up 3.7 hours of duration, and remarkably feature a one hour dip between them, as shown for 60° latitude in the middle of autumn and middle of winter. It’s because post-sunrise begins later in the morning and ends at solar noon, with the sun never rising very high before its arc begins to descend again. Likewise, in the middle of spring and the middle of summer, post-sunset begins later in the evening and ends at solar midnight, whereupon pre-sunrise begins at solar midnight.
Do you have 630m propagation experiences in these SS/SR regimes that have not already been blogged? Your accumulated, experienced wisdom is building our knowledge of 630m for newcomers and old hands alike. TU & GL!”
*The various definitions of near-SR/SS 630m propagation regimes are based on the idea that low sun angle, and consequently low solar ionizing flux, can produce usefully volatile 630m SNR conditions in the absorptive D- region and reflective E/F-regions intermediate between nighttime and full daytime conditions.
Post-SR regime for 630m purposes I define to be the duration of an interval beginning with SR and continuing as long as the sun is no more than 12° above the horizon, the interval not lasting past solar noon (meridian). If the sun does not ascend above the horizon, then post-SR interval is zero; it does not exist.
Pre-SS regime for 630m purposes is the duration of interval beginning the later of solar noon or time from when the sun is no more than 12° above the horizon, the interval not lasting past the earlier of sunset SS or solar midnight. If the sun does not set because the sun does not ascend above the horizon, then pre-SS interval is zero; it does not exist.
**Pre-SR regime for 630m purposes is duration of interval from the later of solar midnight or onset of nautical twilight (dawn) and lasting until the earlier of sunrise SR or solar noon. The pre-SR sun is within 12° below the horizon. If the sun has not set because the sun does not descend below the horizon, then pre-SR interval is zero; it does not exist.
Post-SS regime for 630m purposes is duration of interval from the later of sunset SS or solar noon and lasting until the earlier of solar midnight or the end of nautical twilight (dusk). The post-SS sun is within 12° below the horizon. If the sun does not set because the sun does not descend below the horizon, then post-SS interval is zero; it does not exist.
***Formula derivation & Excel spreadsheet: available on request. Pieces of the formula below involve night length formula at http://njdtechnologies.net/120616/ and +/-12° relative to horizon. I’ve spot checked curves vs. https://www.timeanddate.com/sun/ , errors are only a few minutes.
Additions, corrections, clarifications, etc? Send me a message on the Contact page or directly to KB5NJD gmail dot (com).