Hi Ted,
Congratulations for the beatiful article on 160 meter propagation, which is
going to be published on CQ Magazine, and thanks again for turning at last
your attention to Topband; it's the most complete representation of all the
expected and unexpected phenomena affecting the propagation on our
Band....yes Ted, it's unbelieveable how many different factors are
involved!!
I read the entire article very carefully and you got a new insight into the
160 meter enigma with some really innovative points, followed by my
observations:
1) "Small changes in the density of the D-region can have a profound
influence on absorption levels during the nighttime hours..." : I always
learnt that the D-layer is directly related to the solar zenith angle and
disappears after sunset; it should be interesting to understand and measure
the residual nighttime D-region electron density, which can produce such
large changes in signal absorption, and build an hourly world map.
2) "160-meter signal strenghts are very difficult to correlate with solar
activity.....the correlation with sunspot numbers is only 5 % as strong as
the correlation on higher frequencies"..... some years ago (before DX
clusters and brute power growing) I was used to partecipate in the contests
and also to win sometimes; I will keep your attention Ted on the scores of
the world top winners on 28 MHz and on 1.8 Mhz in the CQWW SSB contest for
the last 12 years:
Year 28 MHZ winner SCORE 1.8 MHZ winner SCORE
1985 TI2KD 549.275 LZ2CJ 89.902
1986 LU1E 754.490 LZ2CJ 89.244
1987 ZY5EG 1.777.508 UG7GWO 255.852
1988 VP2ET 2.423.880 YU3MM 29.169
1989 P40R 2.669.580 IH9/IV3PRK 81.344
(only wkd VE1ZZ in NA)
1990 ZP0Y 2.961.295 UG6GAW 119.955
1991 ZV5A 2.984.166 IV3PRK 28.864
(no QSOs with NA)
1992 ZW5B 2.828.202 9A1HCD 56.550
1993 LU6ETB 1.551.260 IV3PRK 43.751 (only
wkd VE1ZZ and W1ZE)
1994 PQ0MM 1.586.288 IR4T 67.811
1995 LU6ETB 638.388 IG9W 137.020
1996 PQ5W 631.116 IG9/IV3TAN 441.252
3) "Ionospheric Ducting..." : very glad to see another authoritative
opinion on this frequent DX phenomenon, could that explain also the
difficulties I encountered during the month of january on the path to
3DA0CA ? ; I woke up every morning before 04 local time to look for Jon :
he
was almost every day at 03z on 1827.5 working Stateside but I could never
hear him or even the W's calling 5 up; after a week he began working also
North europeans, but I could receive just a wispy signal (339) for a couple
of minutes and never tried to call ...until the 3rd of february when he was
a solid 559 and I got through at the first call ! BTW at the same time the
band was well open also towards USA Middle West and also West Coast
(N6TR/7)...as it was not in the past days.
4) Effects caused by the Auroral Oval..."using Boulder k-indices will not
suffice because Boulder, CO, is far from the auroral ovals. The k-indices
acquired at Artic stations are much more suitable because they are located
within the auroral oval.."; I agree : during the last ARRL Contest the
geomagnetic conditions were quiet with a Boulder k-index of 1, but no QSOs
further than W1,2,3,4 with a few 8 and 9's (and above average stations
AA0RS and K0HA); the obstruction on the path to the West Coast could be
clearly observed on the real time aurora polar pictures.
Regarding CAROS, as I said, I find it impracticable for my regular daily
observations on the band; if you like I'll send you all my papers by mail.
73 Luis IV3PRK
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