TRANSAURORAL HIGH FREQUENCY RADIO PROPAGATION. VOLUME II. SIGNAL MODE ANALYSIS.
High-frequency ionospheric propagation conditions over the 3820-km transauroral Thule-Norwood path were investigated to identify propagation anomalies and reveal their origins in terms of the geophysical environment. Three investigative techniques were employed: (1) step-frequency oblique-incidence...
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| Format: | Text |
| Language: | English |
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1965
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| Online Access: | http://www.dtic.mil/docs/citations/AD0620696 http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=AD0620696 |
| Summary: | High-frequency ionospheric propagation conditions over the 3820-km transauroral Thule-Norwood path were investigated to identify propagation anomalies and reveal their origins in terms of the geophysical environment. Three investigative techniques were employed: (1) step-frequency oblique-incidence sounding; (2) spectrum analysis of 17.7mc signals originating from a frequency-stable transmitter; (3) and film-recording the multipath structure of 17.7-mc pulsed signals transmitted from a continuously rotating directional antenna. The third technique, in addition to providing relative time delays of multipath components, also furnishes the bearing of the signal transmitted from Thule. Propagation at the frequency of primary interest (17.7mc) is predominately via the classical one- and two-hop Flayer modes, although, during the summer months, multihop E sub s modes are observed, particularly at night. The limited available signal-spectrum data suggest that the classical one-hop F-layer signal is often characterized, on magnetically quiet days, by a spread of doppler frequencies of the order of 9.4 cps, or greater, a value substantially greater than the 1/2 to 1 cps observed on temperate latitude paths under similar magnetic conditions. An F-layer ionospheric scatter process is the suggested explanation. (Author) See also AD-620 683. |
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