[Lowfer] Belated report, Friday night WSPR on 630 meters
JD
listread at lwca.org
Sun Jul 13 16:29:14 EDT 2014
Finally got my regular e-mail back this afternoon! Couldn't report
yesterday morning without great difficulty, but I did upload the spots to
wsprnet. Only two stations were decoded the entire night, probably because
of high static levels that set in after sunset (more on that later), but it
was interesting to watch propagation variations in those two signals.
Was seeing XIQ quite well before sunset Friday evening, but it began
undergoing considerable fading about 20 minutes before sunset. It steadied
considerably once darkness fell, even though SNR was impaired by all the
overnight QRN. A similar set of fades occured around sunrise Saturday
morning. The signal was absent almost entirely in one time slot right
around sunrise, then it was back once more just in time for John's final
transmission.
XXM started operation after sunset Friday. By that time, XIQ's signal was
no longer undergoing appreciable fades, but XXM had wide level fluctuations
all night. It always decoded, though, except for when a particularly deep
fade would hit during the WSPR header. This suggests that I was right at
the zone where groundwave and the first hop of skywave were just about equal
strength this time, although in past observing sessions this wasn't
necessarily the case. XXM returned to a rock steady S4 level on the
receiver once daylight returned.
By contrast, the XIQ skywave nighttime was considerably stronger than the
daytime groundwave is here, so the fades were not as dramatic. However,
WSPR missed a lot of decodes of XIQ that Argo at QRSS3 speed suggested were
plenty strong enough to detect! This was especially the case later in the
night, and may have had something to do with the fact that decodes were
taking longer and longer to complete. FWIW, the compatively broad (relative
to WSPR) QRM source just above XIQ was absent here late Friday afternoon and
nearly all the night, but began fading in shortly before sunrise Saturday.
It returned to its traditional level in daylight.
The static I mentioned was apparently from storms well to our north. Before
sunset, and even for a while after, noise reported by the radio was
averaging about S1.5 with excursions to S5 in 250 Hz bandwidth. Prior to
sunset, XIQ was below S1. When I returned after a late supper, noise was
averaging S5 with excursions to S9, then by midnight crept up to S7 with
excursions to S9 and a little above at time. That remained the case until
nearly 3 AM CDT, when noise was down about half an S-unit. I was usually
able to hear XXM quite well by ear, none the less, and sometimes XIQ was
evident too when it started up or shut off. I then napped in the truck from
about 3 to 6 AM, by which time noise was down to S2 with excursions above
S5. By 90 minutes later, average noise was around S1 with peaks to around
S4. The final transmission of XIQ moved the meter to nearly S1.5, and
subsequent daylight path transmissions of XXM were at S4, as mentioned
earlier.
73
John D
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