This session was slow to develop, at least at my station, on the heels of a geomagnetic event in the early evening in North America. Spot counts and signal-to-noise levels were just not up to par during this session as hearing problems were exacerbated by another active storm system located in the central US and bearing to the South. This morning’s CW sked was tough and nulling noise was uncharacteristically difficult due to the location of active weather.
The geomagnetic event resulted in a reporting period at G1 storm levels followed by periods of unsettled activity. A South-pointing Bz and moderate solar wind velocities above 400 km/s characterized the overnight period. Several periods of elevated proton levels were also observed:
Phil, VE3CIQ, was “receive-only” during this session and he decoded VE3EFF, WE2XGR/3, WG2XKA, WH2XGP and WH2XNG.
Toby, VE7CNF, reports that he was “hearing WI2XJQ’s CW on 475.05, RST 339 to 559 with QSB, S2-S4 with noise at S2 in 250 Hz BW.” Similarly Neil, W0YSE/7 / WG2XSV, reported Rick at RST 229 at 0504z.
Ken, K5DNL / WG2XXM, reported poor conditions from Oklahoma, decoding two WSPR stations and being decoded by fifteen, seven of which were by WH2XCR.
Neil, W0YSE/7 / WG2XSV, reports what seems like a relatively poor night as well although his receiving seems to be better:
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 from Vasily’s station at this time.
In the Caribbean, Eden, ZF1EJ, reported WG2XXM and WG2XIQ:
Laurence, KL7L / WE2XPQ, indicates reasonable propagation in spite of the geomagnetic activity:
Merv, K9FD/KH6 / WH2XCR, referencing the hurricane that threatens the Hawaiian islands, provided these comments about his operating plan for the session:
“Storm off to my west now, had about 3 inchs of rain or so, no winds
just some breeze on occasion, this afternoon thunderstorms have
developed and QRN level 30 to 40DB over 9 right now,
Going to fire up and let it run unless I hear some audible thunder.
May not hear anyone perhaps.”
In spite of the storm, Merv did ok although numerous stations have noted limited reports from Merv which is likely the result of the very high noise level.
Jim, W5EST, presents: “VIEWPOINT: APPLETON-HARTREE-LASSEN AND 630M”:
“Today, I begin a progress report on my safari into the theory jungle that begins with the magnetized plasma equation discovered by Lassen (1926), Appleton (1928), and Hartree (1931) (AHL here): https://en.wikipedia.org/wiki/Appleton%E2%80%93Hartree_equation
I’ll state my tentative 630m conclusions first and then begin a multipart “safari” series on AHL. Reread “Three Wrong Assumptions about the Ionosphere” by Eric Nichols KL7AJ, QST 3/2012: 40-42 for similarities and differences.
For 630m, the equations imply new challenges to improve your receiving antenna system. For top receiving performance, first eliminate your local noise problems. Put at least two RX antennas in place that independently receive from different directions or have different azimuth and elevation patterns. Choices include 1) Omni and a fixed or rotatable loop with vertical plane, 2) bidirectional fixed loops set to perpendicular headings, or 3) two loops, one or both rotatable. The idea is to improve the system response to TX stations at different headings, to variations in RF skewed headings, and to variations in polarization to extent such 630m antennas electrically close to ground can capture them.
Couple the receiving antennas to separate receivers RX1 and RX2 as if in a shootout. Unless you have really low band noise, don’t use a combiner that feeds both antennas to a single receiver because that approach will probably just increase the noise and reduce SNR. For CW, try feeding stereo headphones–RX1 to left side and RX2 to right side. For digital modes, run separate, concurrently viewable decoders. For digimodes like WSPR that are supported by a central server, upload the separate decode streams to the central server.
Maybe software will be improved someday with an option to pick the best decode on the fly from multiple streams, and combine the best decodes to form and upload a combined decode sequence. If such software is available now, e-mail us so we can blog where to obtain it.
If you are so fortunate as to have a low noise environment, try phasing and combining the outputs of both antennas to separate right-handed circular polarization from left-handed. Feed the separate circular polarizations to the separate receivers RX1 and RX2, etc., as above.
PART 1: THEORY JUNGLE SAFARI IN E & F LAYERS
Refractive index n measures a substance’s ability to affect the velocity of an electromagnetic wave compared to the vacuum speed of light. As a result, an ionospheric region can bend or reflect a radio wave. An ionospheric region has some atoms that have been ionized–from which electrons have been freed. As a result, the ionized region has some free electrons that can move in response to your radio waves.
Electrons at microscopic scale have a negative electric charge and a very tiny but not insignificant mass that can be accelerated and decelerated by the electric field of your incident RF. (The positively charged ions are so massive by comparison that they respond negligibly to the radio waves.)
As a whole, the ionized gas with its free electrons has a refractive index, like a prism but with some truly magic properties. Refractive index squared is what the AHL formula computes, designated n2.
AHL deduces n2 from Maxwell’s equations and F=ma classical physics applied to free electrons in an ionized gas permeated with magnetic field. AHL assumes that the electric field of radio waves is what mainly affects the motion of free electrons and that ions’ temperature-driven random motion is negligible (“cold” plasma). https://www.plasma-universe.com/Plasma_classification_(types_of_plasma)
Vacuum has a refractive index reference value of unity, 1.0. Air’s index is essentially 1.0, as is the index of spaces between ionospheric regions. Magnetized plasma can have arefractive index n less than 1.0, meaning it supports refraction and may provide total reflection (n=0). “Magnetized plasma” here does not mean the plasma is magnetized as if it were a permanent magnet. It simply means an ionized region has a magnetic field in it, like an ionospheric region permeated with Earth’s geomagnetic field (GMF).
Each ionospheric region has contour surfaces of differing electron concentrations. Each contour has its own refractive index that depends on operating frequency (475.5KHz), on GMF strength, and signal ray orientation Angle “A” relative to GMF.
At high latitudes, that ray orientation is approximately perpendicular to the near-vertical GMF. At medium and low latitudes, the ray orientation on E/W paths is still approximately perpendicular to GMF, which is more nearly horizontal there. On N/S paths the ray orientation becomes more nearly parallel with GMF.
More specifically, refractive index pertains to the ratio of speed of light in vacuum to the phase velocity of light in whatever material. The phase velocity can be more or less than the speed of light in vacuum. Phase velocity is like the apparent ocean wave velocity along a beachfront as ocean waves arrive obliquely. Information-carrying group velocity is what never exceeds the speed of light.
Magnetized plasma confronts an incident RF wave with two refractive indices. The GMF-filled ionosphere consequently splits radio waves into components called O-wave and X-wave, each subject to its own refractive index value there. On a given hop, O-wave and X-wave will find different ionospheric places for reflection high above different geographic locations —if they reflect at all from a given ionospheric region.
A ZL web site shows diagrams of O/X wave trajectories (called O and E rays there). Well worth reading twice! http://www.qsl.net/zl1bpu/IONO/iono101.htm
(To be continued.) Join us tomorrow!”
Additions, corrections, clarifications, etc? Send me a message on the Contact page or directly to KB5NJD gmail dot (com)!