Guy Olinger K2AV asked where the experimental data is.
The foillowing is a short list of Journal articles that go some way towards
answering your question. Any decent University Library should be have
access to most of the journals or be able to access them by inter-library
loan.
.
1. "Effect of Antenna Radiation Angles Upon HF Radio Signals Propagated
Over
Long Distances" W F Utlaut
Journal of Research of the National Bureau of Standards - D. Radio
Propagation Vol 65D, No 2, March -
April 1961, pp 167
2. "Pulse transit times and waveform observations for ionosheric propagation
between England and Australia ( authors including Jack VK3SP)"
Journal of Atmospheric and Terrestial Physics Vol 54, No 4 pp
291-295,1989
3. "On the propagation of short waves over very long distances" K J
Hortenbach & F Rogler
Telecommunications Journal Vol 46 - VI/1979
4. "A test of the importance of Ionosphere-Ionosphere Reflections in Long
Distance and Around the World High Frequency Propagation" R B Fenwick &
O G Villard
Journal of Geophysical Research Vol 68, No 20 pp 5659
5. "Further Studies on the Chordal-Hop Theory of Ionospheric Long-Range
Propagation" Hans Albrecht
Archiv Fur Meteorolgie Band II, series A pp 84-92, 1954
{The first person to work on chordal hop ideas, whilst being an
observer
for Deutsche Welle in Melbourne Australia 1952-1954)
6. "Long Distance Ionospheric Propagation without Intermediate Ground
Reflection"
Report 250 - 6 ITU Conference 1986 (CCIR Study Programme 25D/6)
7. "Investigations on Great Circle Propagation between East Australia and
Western Europe" H J Albrecht
Geophysica Pura e Applicata, Vol 38, 1957 pp169
8. "Propagation Studies on 3.5 and 7 Mcs" H J Albrecht
Amateur Radio, Journal of the Wireless Institute of Australia, Vol
21, No5, 1953 and Vol 24, No 10, 1956
9. "The Role of Layer Tilts in ionospheric Radio Propagation" S Stein
Journal of Geophysical Research, Vol 63, No 1 , 1958 pp 217
10. "An Experimental Investigation of Signal Strength in the area Around a
Transmitter's Antipode" RM Pipp
& J B Webster
Radio Science Journal of Research NBS/USNC-URSI, Vol 68D, No 3,
March 1964, pp 333
11. "The Influence of Chordal Paths on signals Propagating to the Near
Antipode of an HF Radio Transmitter"
Gary E J Bold
IEEE Transactions on Antenna and Propagation, Nov 1972, pp 741
12. "A Long Distance Pulse Propagation Experiment on 20.1 megacycle" R
Silberstein
Journal of Geophysical Research, (1958), pp 445
13. "The Angular Spread of Radio Waves in Long Distance Ionospheric
Propagation" H A Whale
Radio Science, Vol 1 (New series) No 7, July 1966 pp 743
14. "Low-angle Radiation" L A Moxon Wireless World, April 1970, pp155
In each of these articles, there are further references.
By far the most commonly quoted reference (mentioned in ARRL and RSGB
publications) is the Utlaut article which measured angles of arrival between
Boulder CO and Munich, Germany.
In keeping with what Tom N4KG has recently written about summer propagation,
Utlaut's section 4.1 on Diurnal and Seasonal trends makes for interesting
contemplation.
Its also well worth reading the series of articles by Bob Brown NM7M in the
DX Magazine on aspects of propagation, which gives an amateur's perspective
on things.
Cheers
Peter Forbes VK3QI
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