This session probably represents the weakest in the last seven, at least from my perspective. Openings during the evening were unimpressive and overnight only produced a few bright spots including transcontinental reports from WH2XGP at WH2XZO. The path to WH2XCR was closed here in Texas. The noise was low during the evening here but this may have been a symptom of poor propagation. Ken, SWL-EN61, located in Indiana reported that his noise level increased as the session progressed. Neil, W0YSE/7 / WG2XSV, suggests that the lack of stations in British Columbia during this session may contribute to the impression that the band was flat. Activity certainly figures into the equation.
A look at the lightning activity suggests where the problems might have originated from for many of us. The North Central US continues to pummelled!
Geomagnetic activity continues at unsettled levels although the Kp decreased to quiet levels for the most part. The Bz is pointing to the North and providing some protection from the continued elevated solar winds which are currently averaging 590 km/s and were in excess of 600 km/s for much of the session. The DST is improving but the damage may already be done as polar electron reservoirs may be sufficiently full to impact higher latitudes for some time to come:
Larry, W7IUV / WH2XGP, reports very poor conditions from Washington state, decoding three WSPR stations and being decoded by ten unique stations.
Phil, VE3CIQ, reported very quiet conditions with propagation limited to 600 km for his signal. He decoded WSPR signals from VE3EFF and WG2XIQ and was decoded by WA3TTS and WE2XGR/3.
Roger, VK4YB, has been parallel testing WSPR versions and found some interesting results. He also notes weaker propagation and elevated noise:
Just out of curiosity I have been running comparisons of WSPR 2.12 v WSJT 1.6.0. I used two computers but the same sound feed from the Elecraft K3. I believe the decode engines are the same and I was expecting identical responses. I did get near perfect matches for the first few days. Occasionally the WSJT 1.6.0 gave 1 or 2 dB better S/N. Finally I got a decode of WH2XCR at -28 dB S/N that drew a blank on WSPR 2.12, and later another similar one. To be fair the sound cards are not identical. Then I substituted WSJT 1.7.0 on the computer that had been running WSPR 2.12. So far all decodes on 1.6.0 and 1.7.0 have been absolutely identical. I will let it run for another week.
Tough conditions tonight. A line of storms went through Brisbane in the early evening. Lots of visible traces of Merv, but only one decode until now (13:18z).
73 Roger, VK4YB”
John, VK2XGJ, similarly reports a bit of noise and has been listening on JT9 / JT65.
Doug, K4LY / WH2XZO, is beginning to string together a few successful nights back on the air including transcontinental reports of WH2XZO which represent his first West coast decodes in months:
“A single WH2XGP decode was the first west coast spot of the season. Many JT9 signal levels from WG2XIQ with a few approaching CW levels. My receive antenna was with the 3 el Hi Z. Line noise and another unidentified source of noise (plasma TV?) are degrading reception here.
WH2XZO using a Chinese 5W linear amp with an estimated 100 mw ERP was again spotted by 4 stations despite transmitting just 4 hours because of rain and thunderstorms much of the night.
If my antenna top hat remains up, I’ll transmit with the MF Solutions TX converter in a few days which will increase my ERP by 5 or 6 dB.”
A note about these Chinese wideband amps found on Ebay: You MUST MUST MUST use an external low pass filter (not included!) on these units. DO NOT think for a minute that a high-Q antenna system is sufficient for filtering. It won’t even be close. If you need the values of L and C to build your own, contact me and I will be happy to send the numbers to you or look at the W1VD low pass filters for 137 and 472.
Rick, W7RNB / WI2XJQ, reports that he will be QRT for a few days as he works to resolve some thermal issues on his amp.
Neil, W0YSE/7 / WG2XSV, reports that his conditions were improved with reports to and from Alaska. Its nice to see the diversity in conditions, even in close quarters with other stations, and probably says something about local noise. Neil provided the following comments and statistics:
“Gm John. Hearing out to Hawaii this session as well as your signal in Texas…
Hearing: WG2XIQ, WH2XCR, WH2XGP
Laurence Heard me, probably on two different setups in AK this session…
Heard by: KL7L, N6RY, NO1D, WE2XPQ, WH2XGP
Not too bad compared to recent sessions…”
Regional and continental WSPR breakdowns follow:
There were no reports from the trans-Atlantic, trans-African, or trans-Equatorial paths. UA0SNV was present but no reports have been filed at this time.
In the Caribbean, Eden, ZF1EJ, reported my station during the session:
Laurence, KL7L / WE2XPQ, operated a CW beacon through the day, switching antennas to control the pattern as he continues to make seasonal field strength measurements. Laurence also indicates that “XGP nearly in positive figs last night – XPQ rx on probe, Kl7L on main TX Marconish – still raining…” and “…ebb and flow on two rx ants types s/n and polar but interesting – hopefully will do the same tonight between probe and alt tx loop as rx source.”:
Merv, K9FD/KH6 / WH2XCR,had a weird session as multiple important paths were compromised. As previously reported, the normally sound two-way path to VK4YB was weak and noise may have complicated reception reports although conditions seem better closer to and even after sunrise in Hawaii. Along the West coast of North America a number of stations found success on the path to Hawaii:
Jim, W5EST, presents “VIEWPOINT: POWER SPLITTING INTO 630m O/X WAVES. WHAT RX ANTENNAS?”:
“Today I add some plain talk opinion about elliptically polarized waves.
On E/W paths across southern half of USA, most of the vertically polarized TX power stays vertically polarized without power splitting into the horizontal polarization. On E/W paths across northern half of USA and southern Canada, the GMF is more steeply inclined. So, more of the vertically polarized TX power gets split between the O/X-waves—one wave linear-polarized and inclined along the GMF, and the other wave inclined perpendicular to both the path and the GMF. That’s what yesterday’s polarization ratio illustration implies.
Especially on long single hop and on double-hop this splitting means one of O or X will propagate more poorly than X or O. Overall, I think such splitting can contribute a reduction as much as 6 dB on a northerly E/W path compared with a farther-south E/W path. That’s because 1) power splitting and propagation will favor an O or X wave that’s inclined w.r.t. vertical as above (-3 dB), and then 2) a vertically-sensitive RX antenna will favor only a vertical component (another -3 dB) of the tilted incoming wave. I haven’t even mentioned non-uniformities in the 630m E-layer. Nor aurora-related SNR degradation at higher latitudes.
From a given TX station along the way, any elliptically polarized wave combining with any other elliptically polarized wave of whatever phasing and amplitudes makes a composite wave arrive at the RX antenna. Remarkably, any such composite wave is also elliptically polarized. The combined elliptical wave may tilt differently, bulge more or less, and be either stronger or weaker in dB compared to either component elliptical wave.
Our familiar 630m RX verticals and vertical loops are mainly receptive to vertical polarization, of course. If a 630m TX station’s O-wave and X-wave are destructively interfering with each other on arrival, or Faraday rotating far off-vertical, can any practical 630m RX antenna capture available signal that’s arriving and is truly there?
Such O vs. X destructive interference or Faraday rotation would be most likely on signals traversing more nearly N/S paths oriented within +/-45° from the GMF at 1-hop or 2-hop sky reflection. Because 630m signal strength is quite variable, we generally just accept the variability and simply receive better when such destructive interference QSB subsides.
Should that situation acceptable to us? I say, “Not if we can help it!” What can we do?
An antenna that rejects one elliptical polarization (O or X) but not a counter-rotating elliptical polarization (X or O) could improve received signal strength during 630m fades. Elliptical polarization inherently includes a horizontal RF electric field as well as its vertical field. This impels one to seek a 630m antenna that can receive 630m horizontal polarization.
One would need to find a 630m antenna design that can overcome cancellation of horizontal polarization due to ground reflection at high but less-than-heroic antenna heights above ground. Only experimentation would tell if horizontally-polarized band noise contributed by such a horizontally-sensitive antenna portion wipes out any signal strength improvement, leaving SNR no better off. Maybe enough of that noise would be cancellable and not a problem after all.
Could a high-up horizontal RX loop or dipole with preamp be set up to feed down to shack-based combiner circuitry fed as well by a conventional rotatable vertical loop? Should 630m folks experiment with light-weight, low-power microwave links to couple such 630m RX antennas to the shack wirelessly?
Tell us your information about any RX antenna concept that could be effective for acquiring horizontally polarized 630m and combining it with the usual vertical polarized reception!
What we’re talking about here is RX antenna polarization diversity. Wouldn’t it be better to put up one really good conventional 630m RX antenna than add a diversity antenna? …Don’t know! We’re still learning. We’re experimenters. Let some stations try the diversity way and other stations do the best single RX antenna they can. See what works best. Indeed, stations can partner with other stations in their region via their internet screen viewers and get the benefit of longer-baseline diversity in some sense as well. GL!”
Additions, corrections, clarifications, etc? Send me a message on the Contact page or directly to KB5NJD gmail dot (com)!