Last night was typical of midsummer in the northern Hemisphere. Stations across North America were impacted by storm noise from the Midwest because propagation was pretty good. The takeaway message is that the band is serviceable all year long for stations that can manage the noise.
Geomagnetic activity was low and at quiet levels once again. The Bz ranged from unity to slightly South-pointing and solar wind velocities are beginning to decrease below 400 km/s:
It was also noisy “down under”. Roger, VK4YB, reports that the “Base noise is -79dBm, plus QRN from Central Queensland. More storms south of Tasmania. Not looking good.”
Phil, VE3CIQ, reports a new interference source at his station, resulting in a 10 dB S/N penalty. This may be a failure in his E-probe and further investigation will be necessary. He reports that using WSPR he decoded VE2EFF and was decoded by AE2EA, K4LY, KF3F, VE2PEP, W2JTM, WE2XGR/3, and WG2XJM.
Neil, W0YSE/7 / WG2XSV, is working on rig problems and had a relatively successful session. Comments follow:
Ken, K5DNL / WG2XXM, decoded three WSPR stations during the session and was decoded by twenty unique stations including 23 reports from WH2XCR.
Regional and continental WSPR breakdowns follow:
There were no reports from the trans-African, trans-Atlantic, or trans-Equatorial paths. UA0SNV was present during the session but no reports have been filed at this time.
In the Caribbean, Eden, ZF1EJ, reported WG2XXM and WG2XIQ:
Laurence, KL7L / WE2XPQ, decoded WH2XCR and WH2XGP:
Merv, K9FD/KH6 / WH2XCR, had a nice session for July with stations in North America. Noise from storms in Australia results in a difficult session for stations there:
Jim, W5EST, present “PART 3: THE DIODE EFFECT, FACT OR LORE ON 630M?”:
“Today, let’s revisit the July 15 blog section that was discussing diode effect and reciprocity and in part I said:
‘Second, a longer answer confronts questions like: What happens when the ionosphere is involved (RF interacting with dissipative plasma having imperfectly uniform contours, particles raining down, not to mention auroral absorption)? What about Faraday rotation due to the geomagnetic field permeating that plasma? Then what’s the effect on the hypothetical signals going in their opposite directions? What about the O and X waves and gyrofrequency in all this?’
Symmetry of antenna pair/paths TX1-to-RX2 vs. TX2-to-RX1 between stations is a different concept from the concept of reciprocity between antennas at each end of a path. Reciprocity is a theorem involving applied voltage into the TX antenna at a first station and measuring current out from the RX antenna at the other station. Then that same voltage is applied to that same RX antenna at the other station while measuring the current out of the TX antenna at the first station. Reciprocity says the currents would be the same if it’s a linear system. (Probably a purist could state it much better.)
In 2012, a thought-provoking QST article by Eric Nichols KL7AJ, carried the title “Three Wrong Assumptions about the Ionosphere.” (QST 3/2012: 40-42. http://www.arrl.org/qst or on your shack shelf). I’m planning to go back to basics to deepen my understanding of the basic Appleton-Hartree formula describing RF in magnetism-permeated plasma. On p. 42, col. 2, the article tells us:
‘True reciprocity needs to include not only the antenna radiation pattern, but all the intervening paths and processes, which may very well be nonreciprocal. The truth is that Appleton-Hartree all but guarantees that true reciprocal HF paths will be excruciatingly rare….We won’t see this too much on O mode waves, but for X mode waves, the difference in absorption is very different depending on direction.’
Whatever the situation at mid-latitudes, what about 630m paths to/from KL7 and TA paths of transatlantic 630m beaconing between N. America and UK/EU via North Atlantic high latitudes? There the GMF is slanted and strong because it converges near the Earth’s magnetic poles. http://www.ngdc.noaa.gov/geomag/faqgeom.shtml#What_is_the_Earths_magnetic_field
Since an MF/LF station on 630/2200m generally uses different TX and RX antennas, the diode effect question really asks about operational radio station and path symmetry in some sense. The rigorous meaning of reciprocity is essentially inapplicable to the MF/LF stations 630/2200m folks are actually constructing and operating.
As to operational radio station & path symmetry, we are asking whether the radio path would be the same if identical stations transmitted each direction and you tried to match the paths after you spun the globe 180° around an axis line from the center of the Earth through the midpoint of a great circle between those stations.
Whatever the way the radio path geometrically reflects and skews and generally “looks” to RF going each way is exceedingly unlikely to be the same in each direction. But is it enough different to yield a diode effect on 630m? If so, under what conditions?
Here’s another 630m example to consider. (Capitalized call letters mean TX, lower case call letters mean RX).
Compare XPQ-xcr vs. XCR-xpq on the nights of July 8 and 10 when both stations were transmitting each direction.
Laurence WE2XPQ’s 630m WSPR 10 watts as TX1 near Anchorage, Alaska, was received by Merv WH2XCR as RX2 in Molokai, Hawaii . Meanwhile WH2XCR’s 630m WSPR 1 watt as TX2 was received at WE2XPQ as RX1.
On July 10 XPQ-xcr had 9 decodes southbound and peaked -23dB, while northbound XCR-xpq had 22 decodes and peaked -13dB WSPR SNR. Northbound yielded 10dB more SNR with one-tenth the power.
On July 8 southbound XPQ-xcr had 21 decodes and peaked -18 dB, while northbound XCR-xpq had 32 decodes and peaked -10 dB WSPR SNR. 8dB more with one-tenth the power.
But what about the high winds July 8 and antenna problems reported at WH2XCR? Do they account for enough of the difference to discount a diode effect both nights of July 8 and 10? http://njdtechnologies.net/070816/
Would you call it a diode effect? Tell us about diode effect experiences at your station!”
Additions, corrections, clarifications, etc? Send me a message on the Contact page or directly to KB5NJD gmail dot (com)!