BC-DX TopNews WWDXC #945 BC-DX 945
BC-DX TopNews WWDXC #945 BC-DX 945 BC-DX TopNews WWDXC #945 BC-DX 945
The not-so-new result is, that under specific conditions a "near" RTW can and will show a shorter delay as e.g. VoACAP suggests. This has been proven in praxi, as well as the Russian paper from 1975. This paper costs about 32 US-$ to get it from the publisher's electronic resource *... * "Propagation of Round-the-World and Back-Echo signals outside the plane of a great circle". By V.A. Bubnov and G.A. Rumyantsev, UDC 550.388.2:621.373.3 Transmated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 18, No. 9, p. 1383-1386, September 1975. Vor gut einem Jahr hatte ich bei Echo-Zeitmessungen festgestellt, dass die Echos deutlich kuerzer als erwartet waren. Dafuer fand ich - auch in der Diskussion mit Experten - keine vernuenftige Erklaerung. Als ich in diesem Jahr wieder die "verkuerzten" Echos hoerte, bin ich der Sache systematischer nachgegangen und fand ein wissenschaftliches Papier aus der UdSSR von 1975, das ueber den Mechanismus von Grosskreisabweichungen unterrichtete. Diese treten besonders bei Uebergaengen der Hell- und Dunkelzone bei Irregularitaeten der Ionosphaere auf. Dadurch kann sich ein "Rund-um-die-Erde"-Signal in der Laufzeit eben auch verkuerzen. Als "Erste Hilfe" habe ich dazu ein wirklich kleines PDF mit vier Hoerbeispielen verfasst, das zugleich Anregung fuer die multimediale Darstellung solcher Themen sein sollte. Alas, in English, ist eine umfangreichere Version in Deutsch in Vorbereitung. (Nils Schiffhauer-D dk8ok, dxld Feb 21) Wolfy, So what is the cause of this? You don't mention long-path/short path. Let us take 10 megameters as the rough distance between Europe and East Asia, i.e. one quarter around the world. Therefore a long-path signal will travel 30 megameters, three times as far, and 30 minus 10 20 megameters difference. The speed of radio is 300 megameters per second, so 20/300 0.067 second, roughly half the delay reported. In the same way, an LP signal of negligible short-path distance would travel 40 Mm further, which would take .133 second. This is close, and the SP/LP echoes I sometimes hear from WEWN or WWCR which are only 1 Mm away from me, and thus travel 38 Mm further, would be 0.127 second delayed. Single-hop satellite feed delays are quite a different matter, and of course would not affect a single frequency. (Glenn Hauser-OK-USA, Feb 22) 0945 to 1015 UT report, echoes from East Asia. Kunming South China / Udorntani Thailand and Singapore too. 17560XIA 17670KUN 17690JIN 17875ISS 15130BIB 15135KUN 15190URU 15210KUN 15300ISS 15340SNG 15440KUN 15500BEI 15515UDO 13590BEI 13650Jammer 13765UDO (wb) file:///Z|/DOKUMENTATION-BULLETINS/WWDXD-BCDX/2010/BCDX953.TXT[11.06.2012 10:39:53]
#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#* WRTH National Radio Update. Hello ! WRTH National Radio Update of Febr 19th. (Patrick Robic-AUT, A-DX Feb 20) #*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#* vy73 de Wolfgang DF5SX END file:///Z|/DOKUMENTATION-BULLETINS/WWDXD-BCDX/2010/BCDX953.TXT[11.06.2012 10:39:53]
- Page 239 and 240: 48 56 55.74 N 21 15 58.28 E Three
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- Page 247 and 248: 13, via CVC Lusaka Makeni ranch sit
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- Page 251 and 252: BC-DX 953 26 Feb 2010 _____________
- Page 253 and 254: Suaab Xaa Moo Zoo in Hmong from Feb
- Page 255 and 256: am Mittwoch, 24. Februar 2010, live
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- Page 259 and 260: CLANDESTINE RADIO STATIONS. Voice o
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- Page 263 and 264: No sign of any jamming so I guess t
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- Page 283 and 284: SINPO 44433. Female talk till 1035
- Page 285 and 286: und siehe hier: (Theo Averbeck-D,
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- Page 289: full French transcripts on the next
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- Page 295 and 296: (Herbert Meixner-AUT. A-DX M
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- Page 305 and 306: Fuer weitere Informationen steht Ih
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- Page 317 and 318: in 2008: (wb, wwdxc BC-D
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- Page 323 and 324: on FM at 0300-2100 (Unguja 97,4 and
- Page 325 and 326: (Jamie Labadia, dxld Feb 28) Vanuat
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- Page 333 and 334: SDA 1100-1200 Mandarin NoEa-China 1
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- Page 337 and 338: Listen to these samples via the IBB
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WRTH National Radio Update.<br />
Hello ! WRTH National Radio Update of Febr 19th.<br />
<br />
(Patrick Robic-AUT, A-<strong>DX</strong> Feb 20)<br />
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vy73 de Wolfgang DF5SX<br />
END<br />
file:///Z|/DOKUMENTATION-BULLETINS/WW<strong>DX</strong>D-<strong>BC</strong><strong>DX</strong>/2010/<strong>BC</strong><strong>DX</strong>953.TXT[11.06.2012 10:39:53]