In spite of having to shut down at 0630z due to a very small but very lightning-rich cell to the North of my station, propagation and QRN levels were surprisingly good. It was a nice session to return to air after several days of poor weather conditions.
Geomagnetic conditions were extremely quiet with a Bz at or near 0 nT and solar wind velocities that averaged 330 km/s. When we see conditions this quiet, propagation is often found to be poor. The thinking is that there is not enough of a “spark” to move signals.
Steve, VE7SL, was on night two of WSPR transmissions during this session, with reception reports confined to the West coast of North America:
Larry, W7IUV / WH2XGP, reports better conditions, decoding seven WSPR stations and being decoded by 16 unique stations with a decent path to the East.
Doug, K4LY / WH2XZO, reports better conditions as well in spite of nearby lightning where he decoded three WSPR stations and was decoded by 13 unique stations.
Ken, K5DNL / WG2XXM, reports that he decoded three WSPR stations and was decoded by twenty unique stations.
Phil, VE3CIQ, experienced the greatness of the KU4XR “tree-tenna” through this session and offers these session comments:
Neil, W0YSE/7 / WH2XGP, reports that WG2XXM was banging through the “ionic fog” overnight and offers these session comments:
Regional and continental WSPR breakdowns follow:
There were no reports from the trans-Atlantic, trans-African, or trans-American paths. UA0SNV, ZS1JEN, PY2TI, and PY2CAC were present during this session but no reports have been filed at this time.
In the Caribbean, Eden, ZF1EJ, reported WG2XXM, WG2XZO and WG2XIQ:
Laurence, KL7L / WE2XPQ, shared two-way reports with VE7SL, WH2XCR, and WH2XGP. He also reports that VE7SL was up to CW levels during the session:
Merv, K9FD/KH6 / WH2XCR, reports WG2XXM as his furthest eastern station, as well as stations along the West coast and in Alaska. Weather conditions in Australia appear to be somewhat improved, at least as far as lightning in concerned, allowing reports from VK2XGJ and two-way reports at VK4YB.
Jim, W5EST, discusses some QRSS activity from my station with this analysis entitled, “EXPLORE 630M DAYTIME WITH QRSS”:
“The June 1-3 blogs sample some of the QRSS activity and insights available to 630m operators. Today, let’s use QRSS to make a path loss rough estimate on a 630m short path in December daytime afternoon relative to nighttime.
Some days that December time of year, 630m daytime propagation events open up the band. By contrast, the focus here is on a more ordinary day when little or nothing gets through on 630m WSPR2. 630m is the specific subject today. That’s because 2200m is open more often in the daytime over even relatively long single-hop paths.
Recall from yesterday’s blog that the TABLE there indicated the lowest negative SNR that QRSS can probe and still be readable or visible on the ARGO horizontal curtain display. For QRSS30, that number was tabulated -39dB. For QRSS10, the TABLE entry is -34dB, or 5dB less sensitive.
On December 1, 2015, 5 watt WG2XIQ near Dallas transmitted QRSS30 in the afternoon and was visible here at W5EST in Little Rock, see illustration and endnotes.* That means the SNR was at least as favorable as -39dB. XIQ’s QRSS10 daytime signal was unreadable, so the SNR was no better than -34dB. The error in the SNR, with some likely error in yesterday’s QRSS TABLE included, is accordingly estimated to be -39dB +/- 5dB SNR.
Because SNR depends on the characteristics of both the TX and RX stations, estimating the daytime SNR alone tells whether the signal can be received, but not much more about the ionosphere. The next step in this daytime study compares that daytime SNR with SNR in the evening and takes the difference. Taking the difference of SNRs eliminates effects of the TX and RX station constructions and leads to a dB path loss difference between daytime afternoon and evening nighttime.
That December evening XIQ transmitted 5 watts WSPR2 at same power as he had used for QRSS. His SNR at W5EST reached -5dB WSPR SNR by 0044z (1.4hr after XIQ sunset SS). XIQ peaked at +2dB at 0732z (1:32am). I adopted the evening SNR -5dB at 0044z as more representative for comparison purposes.
Next I subtracted the daytime afternoon estimated -39dB+/-5dB SNR from the -5dB XIQ WSPR SNR at W5EST 0044z. I interpret the difference as D-layer absorption. The result is 34dB +/-5dB of D-layer absorption on the 485km Dallas-Little Rock path, at roughly 38° ray elevation angle, in the afternoon of December 1, 2015.
This is good news for 630m! The D-layer is not a daytime brick wall that would have stopped QRSS30 on an ordinary December afternoon. It didn’t.
One might ask whether the signal received over this 485km short path was only daytime ground wave. Was there any received sky wave out there with which to measure D-layer absorption. By way of answer, concurrently KU4XR at 1235km did receive WG2XIQ’s daytime signal (reported 12/2/15 blog). If some XIQ ground wave reached W5EST, it may have offset some D-layer absorption in the calculation, but the stated error allows for D-layer absorption possibly higher than 34dB. Also, you could object that the KU4XR reception signified a 630m daytime propagation event, but daytime 630m events yield WSPR SNRs into the -20s and even the weak teens.
Can you extend or improve upon this SNR differencing method? What would be the daytime absorption other times of day and other times of year, like now? What can you tell us? GL!
*NOTES: WG2XIQ QRSS AS RECEIVED AT W5EST 12/1/15
Time Remarks 12/1/2015 2258z AR SS. 2320z Dallas TX SS. 485 km.
2150-2222z 3 faint unreadable arcs 474.521KHz: TXd qrss10 “XIQ” (5min/arc), RX/argo qrss30 slow.
2224-2242z In “XIQ”: the X is faint daytime prop, and solid IQ is pre-SS prop.
prior to LR AR SS. TXd qrss30 “XIQ” once per 15min arc. RX/argo qrss30 slow.
2250-2306z 2nd “XIQ”: the dahs in X suffered prop. “I” marks LR AR SS. Prop gives
artistic view of an arch as if viewed from the air.”Q” is only slightly rippled by QSB.
ARGO VisGain 32 noise on dark navy background.
(W5EST G33DDC RX dial 473.000 & ARGO 1520 Hz +/- 5 Hz received on noise-cancelled bent 80m attic dipole connected as vertical antenna made of twinlead and top hat.)”
Additions, corrections, clarifications, etc? Send me a message on the Contact page or directly to KB5NJD gmail dot (com)!