It was a noisy night as very active storms in the Midwest and parts of the eastern US made for challenging listening conditions. Geomagnetic conditions were unsettled but for southern stations this may have enhanced propagation while creating a bit of a “mixed bag” for stations further North. Solar wind velocities persist above 500 km/s but this did not deter WH2XGP from making the very long-haul trip to VK4YB, VK2DDI, and VK2XGJ this morning:
Phil, VE3CIQ, reports a tough WSPR session in Ontario, decoding VE3EFF and being decoded by WE2XGR/3.
Neil, W0YSE/7 / WG2XSV, had a bit better session with two-way reports with KH6 and KL7:
Regional and continental WSPR breakdowns follow:
There were no reports from the trans-Atlantic, trans-African, or trans-Equatorial paths.
In the Caribbean, Eden, ZF1EJ, reported my station:
Laurence, KL7L / WE2XPQ, decoded WH2XCR, WG2XSV, and WH2XGP:
Merv, K9FD/KH6 / WH2XCR, experienced two-way reports with VK4YB, decoded VK3ELV, and was decoded by VK2XGJ and VK2DDI. The path to North America was typical.
Jim, W5EST, presents “THE DIODE EFFECT: IS IT FACT OR LORE ON 630M?”:
“The diode effect idea suggests that signals transmitted between the same two TX/RX stations can be received enough differently in SNR that station differences and band noise and local noise cannot explain it. The “diode” label reminds us that an electronic diode conducts in one direction but not the other. The diode effect supposes that RF signals occasionally travel better in one direction between stations than in the opposite direction.
Station differences include the difference between station’s TX power levels, and the difference between TX1-RX2 antenna gains versus TX2-RX1 antenna gains. On 630m, the RX antennas are often separate from the TX antennas, and a variety of RX antennas are in use at different 630m stations.
Although most 630m transmit antennas are top-loaded electrically short verticals, the vertical height, amount and geometry of the top loading (cap hat), and the nature of the grounding system do often vary and produce TX antenna gains that differ between TX stations.
In short, the diode effect idea says that the RF signal path itself is sometimes nonreciprocal. The terrain geometries within the first few kilometers of each station may be complicated, but reciprocity would assert that the path loss should be the same for signals in either direction between the same pair of stations.
A related idea, also regarded as a diode effect, says that the same TX station can received or not received by respective RX stations at similar distances in opposite directions in a way that can’t be explained by their RX antenna differences and noise differences.
Does a diode effect ever happen on 630m? Some instances suggest it might indeed:
- March 4, 2016, 630m WSPR, N. Atlantic diode effect?
Eastward: 3&2&2 spots WG2XKA-f1afj & pa0rdt & g3xkr
Timewise, spots scattered 0124-0506z, SNRs -26 to -30dB.
Westward: DK7FC & F1AFJ both QRV last night, no N. America receptions.
Meanwhile, WG2XKA had best night in a week to wh2xcr in HI.
Could noise from lightning in Carolinas explain lack of transatlantic (TA) decodes in New England the night of March 4? At that southerly storm distance vs. northeast TA heading, is a storm noise explanation a credible objection to the diode effect?
- July 22, 2015, 630m JT9, W.PA WG2XJM to WA WH2XGP diode effect 0513-0518z?
Westward: 0513 -25 0.3 1002 @ CQ WG2XJM EN91
Eastward: 05:15:33 Nothing yet, not even visible trace [at XJM]
Westward: 0517 -26 0.1 1002 @ CQ WG2XJM EN91
Eastward: 05:18:05 switch to bev arrays last cycle, [at XJM] toggling between W and NW and still not a trace.
Eastward: 0524 -26 0.0 1001 @ WG2XJM WH2XGP R-26
Westward: 0525 -24 0.3 1002 @ WH2XGP WG2XJM RRR
Eastward: 0526 -25 0.2 1001 @ TNX 73 GL
Westward: 0527 -26 0.3 1002 @ TU LARRY
Another blog post can discuss the diode effect question some more. E-mail us your most credible experiences to blog regarding a possible 630m diode effect. Stay tuned and stay active!”
Additions, corrections, clarifications, etc? Send me a message on the Contact page or directly to KB5NJD gmail dot (com)!