It was noisy during this session and the source was in my back yard. An approaching frontal system made for a tough evening in North America for many stations. The noise, coupled with later and later DX openings gave many the impression that it was going to be a bust session. A review of my WSPR data for the session suggests that the band didn’t warm up until after 0700z where many signals were at JT9 levels. Al, K2BLA / WI2XBV, in Florida, reports that my signal was in negative, single-digit S/N values, good enough for CW many times during the session. Whether I could have heard other signals is another story. Directional antennas won’t help much when noise sources are found in all directions.
The geomagnetic field was once again relatively quiet. Solar wind velocity remains in the low category, below 400 km/s and the Bz was generally pointing to the North.
Larry, W7IUV / WH2XGP, decoded seven WSPR stations and was decoded by 33 unique stations including reports by John, VK2XGJ, very early in the session and two-way reports with Roger, VK4YB. John provided the following screen capture where Larry’s early signal was very obvious in the waterfall.
Neil, W0YSE/7 / WG2XSV, has a very nice session at 200mW ERP!
Claude, AC0ZL, reported my WSPR signal curiously early, in the 2300z hour, well before sunset here and even longer before sunset in Colorado. There were other uncharacteristically early reports, such as those from K5DRU in Arkansas in the mid-afternoon.
My morning CW sked on 474.5 kHz at 1030z went on as planned in spite of approaching storms. I wanted to test the resilience of the FT-1000 Mark V as a receiver under noisy conditions. The FT-920, normally used for MF and LF, was swamped with noise as expected. I have grown used to managing these challenges on that rig. The Mark V receiver has been very quiet to listen to recently on CW but I didn’t have high expectations in lightning conditions. Surprisingly the Mark V did very well utilizing a combination of RF gain, narrow DSP, RF gain, and noise blanker. Received CW was relatively pleasing to listen to. As the 100W TPO transmitter has become the norm for morning CW here over the combined amplifier arrangement and 3 dB more power, the Mark V is easy to interface to the receive antenna bus. Time will tell how this works out but so far I am very pleased.
WSPR activity was typical for what has been recently observed, with 73 MF WSPR stations reported on the WSPRnet activity page during the evening.
Regional and continental WSPR breakdowns follow:
There were no reports from the trans-African path. UA0SNV was present from Asiatic Russia but had no reports in the WSPRnet database.
Lower latitude trans-Atlantic reports prevail one again, with WD2XSH/17 reporting EA5DOM.
Eden, ZF1EJ, provided a number of reports across North America, including WH2XGP who was on the back-side of the noise.
Laurence, KL7L / WE2XPQ, experienced a bit of an improvement over this session, with a few more stations reporting from the western portions of North America compared to the previous session. There were also typical two-way reports with WH2XCR.
Merv, K9FD/KH6 / WH2XCR, continues to maintain a two-way path with VK4YB plus providing reports for VK3ELV and receiving reports from VK2XGJ. WG2XJM did a great job reporting Merv’s signal from Pennsylvania in spite of noisy band conditions in the south central US.
In Australia, Phil, VK3ELV, returned with reports from JH3XCU. Additionally, he and Roger, VK4YB, each receive reports from WH2XCR, with two way reports for Merv. Previously it was reported that there was an open two-way path with VK4YB at WH2XGP. WI2XBQ also reported VK4YB.
Jim, W5EST, continues his thoughts with, “PART 4: SLIDING WINDOW APPROACH TO 2015-2016 LONG PATH SEASON”:
“Recall that a sliding window is a form of low pass filter. For spiky data like TA and TP that inherently has “high-frequency” content, a low pass filter needs to be used with care or not at all.
I adopt a weeklong sliding window by implementing a plus/minus half-week triangular filter.* (See endnote.) This type of sliding window provides some smoothing while modestly spreading actual spiky information. Results using this one-week triangular window remind us that the season features nearly periodic instances of strong TA.
In the April 9 blog post, spikes of TA and TP got very tall—and not just from propagation variation. The number of paths between transmitting and receiving stations increases with the number m of transmitting stations multiplied by the number n of receiving stations. To make the graphical representation more manageable, I compress the numerical information in the spikes using logarithms. Since logs do not average meaningfully, sliding window averages are executed on the numbers of decodes first. Only then do I take logs.
Recall from February 2, this blog, that 10 log10 of number of decodes of weak signals is also roughly proportional to the number of peak SNR dB above WSPR decoder threshold. The difference of 630m SNRs on different nights approximates 10log10 ratio of decode numbers when the same stations are involved. (Sxjk – Sijk) ~= 10 log10[(Nxj / TX%xj) / (Nij / TX%ij)]]. So, compressing the number of decodes using logs also gives a clue to changes in TA and TP peak SNRs, just so long as you recognize that multiple TX and RX stations are involved in TA–in contrast to the comparison of XGP and XKA I blogged Feb. 2.
See the TABLE for numbers of TX and RX stations yielding over 5 decodes and further columns counting stations yielding at least 1 decode. The peak TA #decode numbers vary with station presence and successes when banner nights occurred. 630m TA is a dance in which participate good propagation and many stations present and effective. The numbers of decodes jointly depend on both the propagation and the stations succeeding with TA or TP. GL the rest of this season!
630M TA: BANNER NIGHTS
DATE #DECODES #TX > 5 #RX > 5 #TX>0 #RX>0
10/5/15 134 4 5 6 10
11/1/15 124 4 4 12 10
12/4/15 83 3 2 3 2
1/1/16 27 1 2 5 7
1/28/16 28 2 1 7 5
3/6/16 48 2 3 4 7
3/30/16 42 5 2 3 11
*An Excel command to compute the sliding triangular window that generated the graphical illustration is: L6=10*LOG10(1+(0.25*J3+0.5*J4+0.75*J5+J6+0.75*J7+0.5*J8+0.25*J9)/3.5)
The graph values are typified by L6. Center day’s number of TP or TA decodes is J6. The triangular window defined by a sum of products based on “weights” .25, .50, .75, 1.0, .75, .50, .25 over seven consecutive days corresponding to decodes J2-J8. Data available on request.”
Additions, corrections, clarifications, etc? Send me a message on the Contact page or directly to KB5NJD <at> gmail dot (com)!