This was another very good, albeit very different session in North America. While this session marks an end (hopefully only temporary!) to the amazing polar openings recently observed, the trans-Atlantic path received a boost, allowing a number of stations to receive reports. The noise level was pretty low for many stations and Phil, VE3CIQ, reported that listening on his transmit vertical, his noise floor was only 15 dB above his dummy load. John, WA3ETD / WG2XKA, reported that this session was not completely noise free for him, although he indicated that holiday lights in his area were quieter so far than in previous years. Here it was a remarkably quiet night again and signals were there for the taking. This morning’s CW session was much of the same. I always have to check to make sure I am routed properly to a receive antenna when the noise floor is this low.
Geomagnetic activity continues to increase ahead of a forecast G1 storm. The Kp is currently at elevated-quiet levels, and the Bz has been tending to the South, straying further and further away from unity. Protons have also been elevated to moderate levels for several reporting periods. Solar wind velocities have not increased from yesterday, with an average near 352 km/s but I expect that to change during the day today or overnight. DST values have decreased to negative levels after a remarkable, multi-day run at high positive levels. Its my guess that when we see DST values at positive values for several days again we will see a return of the polar openings.
Trans-Atlantic reports were more numerous during this session. Its difficult to know whether these openings are enhancements ahead of the impending storm conditions or dumb luck. Phil, VE3CIQ, indicates that he decoded his first trans-Atlantic signal with WSPR reports for Josef, DH5RAE, during this session. WE2XGR also decoded Josef and John, WA3ETD / WG2XKA, shared two-way decodes with him. John also was decoded by DJ0ABR. Ken, K5DNL / WG2XXM, and Dave, AA1A / WD2XSH/17, were also decoded by DJ0ABR and Dave also received reports from Roloef, PA0RDT. We have woven a very intricate trans-Atlantic web during this session. Report details for these stations can be viewed here.
John, WA3ETD / WG2XKA, also had a strong night on the transcontinental path from Vermont and provided these additional comments and plans for the coming session:
“Another very strong session with most of the country well represented. In the spirit of keeping the map clean, XKA again ran a reduced output session – about 120W TPO. DH5RAE was spotted both ways, and a single spot from DJ0ABR was received. This station was also heard by WH2XCR, which is almost a nightly event these days! Tonight I plan on reducing output again by 3 dB to about 50W TPO … we shall see.”
Ken, K5DNL / WG2XXM, reported decodes from 68 unique stations including DJ0ABR, best -24 dB S/N, WH2XCR, best +3 dB S/N, WE2XPQ, best -18 dB S/N, and ZF1EJ, best +9 dB S/N.
As previously reported, Phil, VE3CIQ, experienced his first trans-Atlantic report during this session, decoding DH5RAE. Phil indicates that due to a test he was performing he was only transmitting at about one quarter of his normal power but expects to be at full power tonight in hopes of being heard in Europe.
Toby, VE7CNF, reports that he decoded eleven WSPR stations and was decoded by 45 unique stations.
Neil, W0YSE/7 / WG2XSV, reported “…the band is quiet this morning with a temp of 27F, but last night there was a bit of elevated noise. Not sure what it was because it was not raining or snowing at that time.“
Rick, W7RNB / WI2XJQ, reports an overnight temperature in the 20’s F and improved base current as a result. Rick also had success running WSJTx on a Mac overnight so expect more details on that in the near future. Rick provided WSPR reports for eleven stations (plus one bogus report) and was reported by forty unique stations. Rick’s unique report details can be viewed here.
Trans-Pacific report details for mainland North American stations (excluding KL7) are aggregated here.
Ward, K7PO / WH2XXP, received reports from 68 unique stations, including 7L1RLL4, JA1NQI-2, JA3TVF, JH3XCU, and VK2XGJ.
Larry, W7IUV / WH2XGP, received reports from 54 unique stations, including JA1NQI-2 and VK2XGJ.
This session started immediately following my morning CW session yesterday, returning to WSPR for the day and receiving consistent ground wave reports from K5XL 15-20 miles down the escarpment from my station. At 2229z, Ken, SWL-EN61, located in Indiana, reported the first daytime “skywave” decode of the session for my station and followed up that report with another a few minutes later. The flood gates opened 20-30 minutes before sunset here with reports into the East and Midwest. It was a good night, with quiet band conditions here in Texas and seemingly early reports of stations in the Pacific Northwest.
I found a problem with my setup of the temporary backup PC that pressed into service with a hard drive failure on the primary MF machine. It turned out my receive audio was ported into the wrong jack on the sound card. As a result, levels were down by several orders of magnitude. If I decoded your WSPR signal on Monday night or during the day or early evening on Tuesday, you were doing very well as your signals would have been greatly attenuated. Reports were back to normal once I moved the plug to the proper jack. It was nice to receive and be received by WE2XPQ again.
I operated a short bit of JT9 during the mid-evening, receiving reports from Mark, WA9ETW / WI2XHJ, in Wisconsin. Mark noted that while my WSPR signal had been in the single-digit negative S/N levels, my JT9 was reported in the upper teens. This may have been the result of JT9 losing a big of advantage due to the shorter transmission cycle compared to WSPR, or a fade or most likely a momentary drop out of the exciter due to an ongoing thermally-motivated ALC problem. I hope to do a little more JT9 in the evenings. Its been quite a while since I consistently operated the mode and I know there are operators that are interested in JT9 QSO’s that are workable. Morning CW was normal with reports from Eden, ZF1EJ, at 1124z at RST 539. No additional QSO’s were reported during this session. My WSPR transmission reports can be viewed here and my WSPR reception reports can be viewed here.
More high activity was observed during this session with 107 MF WSPR stations reported on the WSPRnet activity page at 0100z. Kevin, KB9RLW, was a new reporting station for this session and John, WA3ETD / WG2XKA, received an email from Kevin, indicating that John was the first station he received on 630-meters. Kevin is using a Kenwood TS-440SAT with a 98-foot long end-fed wire, coupled to the receiver using a home brew 6.5:1 UNUN at the feed point of the antenna. The wire peaks at nearly 30 foot above the house and is at its lowest about 9 foot above the ground. Kevin is hearing well with a stock 440. Congrats and welcome aboard!
Regional and continental WSPR breakdowns follow:
Eden, ZF1EJ, has entered into a nice pattern of receiving stations across North America as well as daily reports for WH2XCR in Hawaii. Eden provided reports for VA7MM, VE3CIQ, VE3EFF, VE7BDQ, VE7CNF, WD2XSH/15, WG2XIQ, WG2XKA, WG2XSV, WG2XXM, WH2XCR, WH2XGP, and WH2XXP. Report details for these stations can be viewed here.
Laurence, KL7L / WE2XPQ, began his activity around 0545z, decoding JA1PKG and receiving reports from 7L1RLL4, JA1NQI-2, JA3TVF, JH3XCU, and VK2XGJ. He reported very strong signals from WH2XCR. Laurence was also decoded here which has become relatively common this year . He is doing something right. His report details for JA, VK and KH6 can be viewed here.
Merv, K9FD/KH6 / WH2XCR, reported that he QRT’ed prior to sunrise this morning, but managed to provide reception reports to ZL2BCG this morning. He also received WSPR decodes from JA1NQI-2, JA1PKG, JE1JDL, JH3XCU, and VK2XGJ. Its nice to the see path to Oceania return. Merv also shared two-way reports with WE2XPQ and was hearing well into New England and the eastern US. Merv JA, VK, ZL, and KL7 report details can be viewed here.
Jim, W5EST, presents, “RULE OF THUMB AND BIRDSEYE CHARTING TIME OPPORTUNITY WINDOWS”:
Today’s blogpost tells why I propose a rule of thumb for 630m time opportunity window W duration and use a birdseye chart illustration of night lengths with it. Longer and shorter night length get signified TL & Ts at 630m stations respectively. NTZ is roughly the number of time zones between the stations. Examples are plotted for KH6-LA2 and KL7-LA2 on a birdseye chart.
Rule of Thumb: 0 ≤ W + NEhops ≤ (TL + Ts)/2 – NTZ ≤ Ts.
Over the last two days this blog has discussed, first, an SNR bullseye diagram http://njdtechnologies.net/120516/ that spreads 630m DX nighttimes around the 24 hour UTC clock like pizza wedges. Then yesterday’s blog showed a birdseye chart – a worldwide set of curves showing duration between sunset SS and sunrise SR for stations at various latitudes and times of year. http://njdtechnologies.net/120616/
For most 630m paths, sky wave reception is approximately bracketed by the interval between SS at the westward station and SR at the eastward station. Of course, 630m sky wave reception can commence before and extend beyond the SS-SR interval especially in fall and winter, and 630m daytime propagation events may intervene not only then but any time of year.
Even so, the SS-SR interval is a very useful reference that tells us about how long common darkness lasts on a given path. You can estimate the length of that interval one way by looking up the SS and SR times for each station and then figuring their difference. https://www.timeanddate.com/sun/
Now let’s seek more comprehensive understanding of the way the SS-SR interval “works” or varies for various paths around the world. To do this, imagine two stations having identical solar midnight times because they are at same longitude. On the bullseye diagram, two pizza wedges representing each station’s nighttime would be centered on each other because the two stations have same solar midnight (same longitude). The opportunity time window for the path between the two stations would be equal to the time duration Ts (pizza wedge angle) of the shorter of the two station night times. One station nighttime would be shorter than the other due to a difference in their latitudes.
Now suppose that the stations are also offset in longitude so that their solar midnights are displaced by an hour-difference amount NTZ corresponding to rotation at 15° per hour of one of the pizza wedges through a geographic longitude difference +/-NTZ 360°/24. For back-of-envelope estimation, you can just call NTZ the number of time zones between the stations if you like. On 630m we mostly care about paths that share some common darkness. The SS-SR duration lies in this range: (See endnote 1*)
0 ≤ (TL + Ts)/2 – NTZ < Ts
You know NTZ from the longitude difference, or roughly the number of time zones between the stations. Moreover, you may have noticed that (TL + Ts)/2 for any time of year is easy to figure on the birdseye chart, see today’s illustration. Simply go halfway between the night hour curves at the latitudes of each station. (Then by subtracting NTZ, you can also use the birdseye chart to guesstimate numbers of weeks and favorable times of year when the SS-SR interval is at least a given number of hours. More about that in another blog post.)
The only comment I’d add from experience with WSPR database is that the path distance somewhat independently comes into play and reduces the useful duration– what you can call a time opportunity window W. You can estimate path distances from: https://www.daftlogic.com/projects-google-maps-distance-calculator.htm Click and leave your mouse on a particular location temporarily, and that app returns its latitude and longitude too.
Let’s use the number of E-hops,** (usually path distance/2500km rounded-up), as a proxy for a further reduction in opportunity time window hours, which leads me to:
Rule of Thumb: 0 ≤ W + NEhops ≤ (TL + Ts)/2 – NTZ ≤ Ts.
Today’s KH6-LA2 and KL7-LA2 illustration estimates and compares December time windows W for these two paths. Steps “A” and “B” identify the night lengths at latitudes 63°N (LA2) and 21°N (KH6). In step “C” plot point P1 halfway between them. Lines L1 and L2 approximately show the halfway values for (TL + Ts)/2 on other dates. Next, step “D” deducts 11 time zones, and then step “E” deducts for 5 E-hops on a proposed 10500 km KH6-LA2 path. Step “F” determines KH6-LA2 time window in mid-December is zero hours, virtually none. The KH6 RF signal has its work cut out for it!
The steps for KL7-LA2 are analogous. By comparison, KL7 in the Anchorage area is roughly the same latitude as LA2 which yields point P4 and provides about 2 night-length hours advantage. One (1) less hour of longitude difference turns up, and 2 fewer E-hops for KL7 to reach LA2. This procedure on the birdseye chart suggests that KL7-LA2 opportunity extends over a few hours of 630m time window to LA2 regardless of whether that many hours actually get occupied with fortunate decodes any particular December night.
Any rule of thumb calls for more testing and can probably be outperformed by your 630m successes. For 630m paths that folks are already exercising, we have some intuition about the time windows. The Rule of Thumb and birdseye procedure not only can help organize our intuition. They also provide a way of considering possible future 630m paths across to and between parts of the world that currently have no 630m activity.
If you already have a rule of thumb that you use to estimate time opportunity windows, let us know and we’ll be happy to blog it. TU & GL!”
*NOTE 1: The path’s nighttime duration remains equal to time duration Ts of the shorter of the two station night times as long as NTZ ≤ (TL – Ts)/2. That’s the difference between the pizza wedge angle-halves. When the hour-difference NTZ gets sufficiently large, however, then the SS-SR duration declines with longitude difference as follows. Then the sum of pizza wedge angle-halves becomes involved, which is the average of stations’ night lengths.
Ts – [NTZ – (TL – Ts)/2] = (TL + Ts)/2 – NTZ.
The two stations share no common darkness when their pizza wedges fail to overlap on the bulls-eye diagram. That condition occurs when NTZ >= (TL + Ts)/2.
**NOTE 2: Specifically it’s E-hops that are to be counted because I think some paths, such as paths across the equator and wintertime paths in polar regions might have fewer E-hops than a simple distance formula suggests. The formula ignores different TX power levels, different TX and RX antennas and their patterns and orientations, and possible storm noise conditions in the RX station’s region. The objective is to estimate a window of opportunity, not necessarily results.
Additions, corrections, clarifications, etc? Send me a message on the Contact page or directly to KB5NJD gmail dot (com).